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GNU Astronomy Utilities NEWS                          -*- outline -*-

Copyright (C) 2015-2025 Free Software Foundation, Inc.
See the end of the file for license conditions.

* Noteworthy changes in release 0.24 (library 22.0.0) (2025-11-26)

** New publications

  - https://arxiv.org/abs/2510.12940v1 by Eskandarlou et al. that describes
    the latest status of our scripts to extract and subtract the extended
    PSF of bright stars in the J-PLUS survey. See Figure 1 (for an outline
    of the flow chart) and Figure 6 (on a nice demo of the effect). It
    builds upon Infante-Sainz et al. 2020 (which was the basis for
    Gnuastro's 'astscript-psf-*' scripts) and like that paper, this one is
    also fully reproducible so you can go inside its public source code to
    check every step (see Section 6 for the links).

** New features

*** Arithmetic

  - New Operators: similar operators are grouped; groups are sorted
    alphabetically by first operator in the group

    - filter-minimum:
    - filter-maximum:
    - filter-sigclip-std:
    - filter-madclip-mad:
    - filter-sigclip-std:
    - filter-madclip-mad:
      Replace each pixel with the respective statistic of the pixels in the
      given filter size. These are useful when you need to measure the
      spread of nearby pixels (in the presence of outliers).

    - label-area:
    - label-minimum:
    - label-maximum:
      Given a labeled and a values image do the requested measurements on
      the label and set the label's pixels to the output of the measurement
      in the output. For example, if you want to remove all labels with an
      area less than 3, you can use the 'label-area' option followed by the
      'gt' (greater-than) operator. Until now, to do this, we needed to run
      MakeCatalog, extract the rows, and write loops to remove the labels
      one by one (which was slow, in efficient and could by buggy). These
      new operators greatly simply such operations while significantly
      improving the speed. See example usages within the book.

    - luminosity-to-mag:
    - mag-to-luminosity:
      Convert apparent magnitude to luminosity and vice-versa. Implemented
      by Sepideh Eskandarlou.

    - madclip-all:
    - sigclip-all:
      Return all available statistics after clipping outliers (mean, std,
      median and MAD and number of used datasets).

    - sblim-diff: calculate the expected difference in surface brightness
      limit (purely based on exposed area (of the telescope) and exposure
      time (assuming the same filter, sky conditions and assuming no
      correlated noise). This can be used for planning projects with
      different telescopes, but be careful about filters and atmosphere.

*** ConvertType

  --cmapblankcolor: Name of color to use for blank values when showing
    single-channel images through a colorbar. This is very useful in
    scenarios where you don't want your audience to confuse NaN pixels with
    pixels that have data. For example if you use the Viridis colormap, you
    can set '--cmapblankcolor=white' or '--cmapblankcolor=red' (which do
    not exist in the Viridis color map). Note that this option does not
    apply to the "gray" colormap because that is single channel. To get the
    list of recognized colors in Gnuastro run 'astconvertt
    --listcolors'. This was suggested by Sepideh Eskandarlou.

  --cmappgfplots: create a second output file containing the PGFPlots
    colormap definition for single-channel data that are to be displayed
    through a colormap. PGFPlots is a powerful plot creation package within
    LaTeX to create high-quality plots and figures in your papers, slides
    or reports. With this option, you can use Gnuastro colormaps that are
    not available in PGFPlots. The "Annotations for figure in paper"
    section of the book has a fully working example of the usage of
    PGFPlots in combination with Gnuastro for high-quality figure
    generation.

*** MakeCatalog

  --novalinerror: ignore pixel in the values image when calculating the
    variance of each label's pixel: only use the pixel's value in the
    '--instd' image (which can also be the variance with the '--variance'
    option). This is useful in scenarios where the STD/variance image is
    not just the sky STD/Variance, but also has the signal's contribution.

  --mean-error: Measure the error of the mean for each label (object or
    clump).

  --meta-measures: new option to print metameasurements (measurements on
    measurements) as keywords in the 0th HDU of the output. These include
    the measured surface brightness limit, the noise-based magnitude limit
    and the confusion limit. Until now, only the first was always
    automatically measured, but from this version, if you need to call this
    option to get it (the keyword names have also changed, see "MakeCatalog
    output keywords" section of the book). For more, see the newly added
    section in the book called "Metameasurements on full input".

  --nml-sigma and --nml-area: the multiple of standard deviation and area
    (in square arcseconds) to use for the noise-based magnitude limit (also
    called "detection limit" by some authors).

  --cnl-with-objects: measure the confusion limit using objects instead of
    clumps (only recommended if you are not generating your labels with
    Segment).

  --cnl-check: add an extra HDU to the output that contains the distances
    to the nearest neighbor of each row used in the confusion limit.

*** Match

  - Ambiguous matches (multiple counterparts in other catalog within
    aperture) will not be present in the main output. When present, the
    ambiguous rows of the second input will be listed in a dedicated HDU of
    the output (called 'FLAGGED-IN-2ND'). A dedicated new section (called
    "Unambiguous matching") has been added to the book that describes the
    intricacies of this new behavior.

  --arrange: the arrangement of the match output. Until now, the Match
    program only had the 'inner' arrangement (known in SQL as "INNER
    JOIN"). From this version, other arrangements are also available and
    fully described (with example tables and short tutorials) in the newly
    added "Arranging match output" section of the book. A short summary of
    the new arrangements is given below:

    - full: known as "FULL OUTER JOIN" in SQL. Its output has both the
      matched rows and the non-matched rows in one catalog.

    - outer: known as "RIGHT OUTER JOIN" in SQL. Its output has the same
      number of rows as the second (query) input catalog to Match, giving
      the ability to find the (possibly repeated) matching rows from the
      first (reference) catalog. See the demo for a real-world example.

    - outer-within-aperture: similar to 'outer', but if the nearest
      reference catalog entry is more distant than the given aperture, it
      will be NaN/blank in the output.

*** Statistics

 - Polynomial fitting is now possible for 2D inputs: given either as an
   image (assuming the pixel's horizontal and vertical positions are the
   independent variables) or as a three columns (where the first two are
   independent variables). A new "Two dimensional polynomial fitting"
   section has been added in the book to demonstrate its usage.

*** astscript-ds9-region

  --fontsize: new option to allow setting the font size of the values
    within the name column (given to '--namecol'). The values of the name
    column are printed as text on top of each region in DS9.

*** astscript-fits-view

  --topcat4k (or '-k') option is added for easy display on 4K monitors
    (where the TOPCAT window can be very small by default).

*** astscript-radial-profile

  --azimuth option can be called multiple times so the profile is generated
    over discrete azimuthal regions of the input. For example if called
    with '--azimuth=30,50 --azimuth=210,250', the profile (or polar plot if
    requested) will be generated only using pixels within these two
    azimuthal ranges (all other pixels are ignored). Suggested and
    implemented by Ignacio Ruiz Cejudo.

*** Makefile extensions

  - $(ast-text-next TARGET, LIST): returns the next word (after TARGET) in
    the input LIST; see the documentation for more.

  - $(ast-text-next-words TARGET, NUM, LIST): returns the next NUM words
    after TARGET from LIST.

*** Library

  - gal_data_append_second_array_to_first_free: for easily appending
    (adding the contents of the second array into the first) in
    single-dimensional datasets.

  - gal_dimension_image_to_table: function to extract all non-blank
    elements of an image and save them into a table with their pixel
    coordinates (first two columns) and pixel value.

  - GAL_FIT_MATRIX_INVALID:
  - GAL_FIT_MATRIX_POLYNOMIAL_1D:
  - GAL_FIT_MATRIX_POLYNOMIAL_2D:
  - GAL_FIT_MATRIX_POLYNOMIAL_2D_TPV:
    Macros to identify different types of fitting matrices.

  - GAL_FIT_MATRIX_NUMBER_1D:
  - GAL_FIT_MATRIX_NUMBER_ALL:
    The number of 1D matrices and total matrices used in fitting.

  - gal_fit_polynomial_tikhonov: new function to perform a regularized fit
    using Tikhonov regression, wrapping over the GNU Scientific Library
    (GSL) functions.

  - gal_kdtree_range: returns the list of points that are within a given
    radius of the given point. Implemented by Barış Güngör.

  - gal_label_measure: Replace a label with measured values over it (see
    description of newly added 'label-*' operators in Arithmetic).

  - gal_list_sizetsizetf64_add:
  - gal_list_sizetsizetf64_pop:
  - gal_list_sizetsizetf64_free:
    New functions to use a new list type that includes a 'size_t' and a
    'double'.

  - gal_statistics_minimums_three: return the three smallest values of the
    given dataset.

  - gal_statistics_range_double: return the difference between the minimum
    and maximum as a double-precision floating point of a dataset (with any
    type).

  - gal_tile_per_label: create an array/list of tiles that cover the
    separate labels within the input.

  - gal_table_sort: sort the given table by a given column.

  - gal_units_sblim_diff: calculate the difference in surface brightness
    limit only assuming a different effective radius of a different
    telescope and/or a different exposure time.

  - gal_units_mag_to_luminosity:
  - gal_units_luminosity_to_mag:
    Convert the observed magnitude of an object to luminosity and
    vice-versa.

  - gal_units_wavelength_flux_density_to_jy: convert given wavelength flux
    density (erg/s/cm^2/A) to Janskys.

** Removed features

  - Nothing has been removed in this release.

** Changed features

*** Book

  - The term "stack" was used in two contexts within the Arithmetic
    program: referring both to the stack of operands during its operation
    and the coadding process (when we add many images to make a deeper
    one). When talking about the latter scenario, the book now uses the
    term "Coadd" (which is also commonly used in the optical astronomical
    community).

  - The sub-sections of MakeCatalog's old "Quantifying measurement limits"
    section (which described individual source errors as well as
    metameasures over the whole image) have been distributed in other/new
    sub-sections following MakeCatalog's new approach to metameasures as
    described above in the new '--meta-measures' option.

*** All programs

  --cite: also prints the citation for the Gnuastro book/manual (using the
    Zenodo DOI for that release).

*** Arithmetic

  - Operators:

    - interpolate-minofregion:
    - interpolate-maxofregion:
      Now take three operands (in order of popping): the outer
      connectivity, the inner connectivity and the image with blank
      pixels. Until now, it took only the inner connectivity and the outer
      connectivity was hard-coded to the maximum of the input's
      dimensions. This was necessary because it can happen that the most
      permissive outer connectivity may be too loose in some usage
      scenarios. To get the same output as before in your existing scripts,
      add a '2' before the operator (for an image) or (3 for a cube).

    - madclip-*: when the MAD is zero (median is repeated; mostly occurs on
      integer inputs), an alternative to the MAD will be used (difference
      between the two differing values just before and after the median in
      a sorted array). This greatly helps the usability of MAD-clipping on
      integer datasets with small scatter (where the median can be repeated
      a lot).

  --append: when called with this option, Arithmetic will not write its
    run-time option values in the 0-th HDU.

  --metaname: can now accept multiple values (names of each HDU for
    multi-output calls of Arithmetic).

  --metaunit: similar to '--metaname'

  --metacomment: similar to '--metaname'

*** Crop

  - The log-file name (created when run with '--log') is based on the
    output file name (see the description of '--log' under the Crop program
    for the details) and is a FITS table with a suffix '-log.fits'. Until
    now, the log file was always called 'astcrop.log' and it was created in
    the running directory. This would cause problems for parallel
    executions. Also, it was a plain-text file which is less efficient:
    slower to read and write and would be larger for longer catalog inputs.

*** MakeCatalog

  - The output should always be a FITS file. This was necessary because
    with the metameasures, more and more tables may be requested by the
    user. Also, keywords are becoming more important and and supporting
    both text and FITS was becoming a major development overhead because
    plain-text doesn't support multiple tables per file or keywords.

  - All the metadata keywords of all the tables are now written in the 0th
    HDU. Until now, they were written in all the produced tables that was
    inefficient and confusing; this is part of an already started project
    for all Gnuastro programs to write all their metadata in the 0th
    HDU. The new "MakeCatalog output keywords" section in the book fully
    describes all the output keywords, please check that section for all
    the new keyword names. The most significant is the surface brightness
    limit keyword(s), that have now been distributed and renamed to fit the
    new metameasure structure.

  --sbl-sigma: new name for the old '--sfmagnsigma', as part of the process
    to standardize metameasures.

  --sbl-area: new name for the old '--sfmagarea', as part of the process to
    standardize metameasures.

  --forcereadstd has been removed in favor of the more general
    '--meta-measure' option. This is because it was only useful for
    calculating the surface brightness limit (which is a metameasure).

*** Match

  - Ambiguous matches (when more than one object is within the given
    aperture) are flagged and kept in a new HDU of the output. A new
    "Unambiguous matching" section has been added in the "Match" section of
    the book to describe this important feature.

  - Output can only be in FITS format. Until this version, the output could
    be plain-text also. However, plain-text tables can only be a single
    table, so multiple files where necessary when multiple tables were
    created. Managing all the files in the various run-time scenarios was
    causing a significant slow-down of the development and was also bugging
    (for example '--logasoutput' which was not thread-safe). If a
    plain-text format is necessary in your pipelines, you can call
    Gnuastro's Table program to convert the given HDU into plain-text.

  --outcols: can now be invoked multiple times in one command. Until this
    version it was only possible to call it once, causing inconveniently
    long options for large tables. This was suggested by Sepideh
    Eskandarlou.

*** astscript-ds9-region

  - The default coordinate system to write WCS coordinates for DS9 is now
    ICRS. Until now, it was FK5 (based on the default system that DS9 would
    propose for writing regions). But DS9's latest versions have changed to
    ICRS, so we are also doing the same here. In practice, the difference
    is very small and only relevant for extremely precise positioning.

*** astscript-pointing-simulate

  --coadd-operator: new name for '--stack-operator'.

*** astscript-zeropoint

  - The default matching radius for stars has been changed to 0.5
    arcseconds. Until this version it was 0.2 arcseconds.

  - If less than three stars are matched between the reference and query
    catalogs, the script will abort with an elaborate error message
    (guiding you on how to fix the problem. This is because the result will
    not statistically reliable.

*** Library

  - gal_blank_remove: new 'free_if_all_blank' to enable optional freeing of
    the input array when all elements are blank.

  - gal_kdtree_nearest_neighbor: new name of 'gal_kdtree_nearest_neighbour'
    which was in British English (Gnuastro uses American English).

  - gal_match_kdtree: a new 'arrange' and 'flag' argument have been added
    to define the arrangement of the output.

  - gal_match_sort_based: a new 'flag' argument has been added that will be
    filled if there are ambiguous matches.

  - gal_table_write_log: a new 'format' argument is added to allow setting
    the format of the table (until now, it was always plain-text).

  - New names for the fitting library functions (old --> new). This is
    because (as described in the new features), the fitting functions have
    generalized to also accept 2D inputs.

    - gal_fit_1d_linear --> gal_fit_linear_1d
    - gal_fit_1d_polynomial --> gal_fit_polynomial
    - gal_fit_1d_polynomial_robust --> gal_fit_polynomial_robust
    - gal_fit_1d_linear_estimate --> gal_fit_linear_no_constant_1d
    - gal_fit_1d_linear_no_constant --> gal_fit_linear_no_constant_1d

** Bugs fixed

  - bug #66043: One pixel offset in PSF subtraction.

  - bug #66216: NaN values in MakeProfile outputs for very small profiles
    (smaller than a pixel even after accounting for the truncation
    factor). Reported by Alejandro Camazón Pinilla.

  - bug #66262: color-faint-gray crashes when using --graykernelfwhm. Found
    and fixed by Samane Raji.

  - bug #66280: Convolve's check images not in same directory as output.

  - bug #66303: astscript-color-faint-gray crashes if using 4th
    channel. Reported by Elizabeth Sola and fixed by Raul Infante-Sainz.

  - bug #66308: Library's 'gal_wcs_img_to_world' and 'gal_wcs_world_to_img'
    returned inverse names when the operation was not in-place. Found and
    fixed by Giacomo Lorenzetti.

  - bug #66309: Match crashes if kdtree is not set. Found and fixed by
    Giacomo Lorenzetti.

  - bug #66572: MakeProfiles continues adding pixels after truncation when
    the profile is small (a couple of pixels), and the gradient is strong.

  - bug #66588: Arithmetic's 'trim' operator does not produce 0x0 image
    when all the image is blank.

  - bug #66657: gal_fits_img_read not passing hdu_option_name; found with
    the help of Sepideh Eskandarlou.

  - bug #66693: MakeProfile crashes with segmentation fault with when
    --customimg is given and the oversampling factor is larger than 1.

  - bug #66867: Example added in book to show how to remove outputs of
    Query's '--overlapwith' option when sources outside of the image are
    also retrieved (for example due to a rotated image or the server not
    accounting for spherical distortion). Reported by Raul Infante-Sainz.

  - bug #66869: Crop segmentation fault leading to unpredictable return
    values. Reported by Raul Infante-Sainz.

  - bug #67105: astscript-radial-profile produced unreasonable output when
    undersample was given as one. Reported by Samane Raji and fixed by Raul
    Infante-Sainz.

  - bug #67106: Crash during build when Ghostscript is not
    present. Reported by Faezeh Bidjarchian.

  - #67128: Maskfilled operators wrong output with zero scatter (can happen
    in integer images, for example in the creation of master dark frames).

  - bug #67190: Sorting an empty plain-text table gives segmentation
    fault. Reported by Sepideh Eskandarlou.

  - bug #67191: Arithmetic does not parse '-inf' as a number on the
    command-line and complains with an invalid '-i' option! Reported by
    Sepideh Eskandarlou.

  - bug #67204: Table's --equal operator cannot be called multiple times on
    same column with different values.

  - bug #67232: Building failure on i686 architectures (32-bit).  Reported
    by Benson Muite and fixed by Giacomo Lorenzetti.

  - bug #67275: Segmentation fault in MakeCatalog during clump catalog
    generation when input labels not contiguous (for example you are
    feeding a crop of a larger object/clump map).

  - bug #67297: Fits program segmentation fault when no input specified and
    a HDU operation requested.

  - bug #67364: Match's k-d tree based inner matching depends on order of
    inputs. Fixed by Barış Güngör.

  - bug #67475: Statistics fitting output prints 0 when the values are very
    small. Reported by Faezeh Bidjarchian.

  - bug #67684: Match's full-arrangement with outcols produces an empty
    output when there is no match. Reported by Sepideh Eskandarlou.





* Noteworthy changes in release 0.23 (library 21.0.0) (2024-07-13)
** New publications

  - https://ui.adsabs.harvard.edu/abs/2024RNAAS...8..168E by Eskandarlou
    and Akhlaghi describing the newly added polar plot capability of
    'astscript-radial-profile' (see the figure in the paper).

** New features
*** Arithmetic

  --append: if the output file already exists, don't delete it, add the
    outputs as extra HDUs (by default, the output file is deleted). If the
    output does not exist, then this option has no affect.

  - New operators (also available in "Column Arithmetic" of the Table
    program):

    - jy-to-wavelength-flux-density: converts Janskys to wavelength flux
      density (erg/cm^2/s/Å) at the given wavelength.

    - filter-madclip-mean: filter/smooth the input using MAD-clipped mean.

    - filter-madclip-median: filter/smooth the input using MAD-clipped
      median.

    - free: free (from memory) the top operand on the stack of
      operands. This is useful in combination with operators that produce
      more than one output operand.

    - madclip-maskfilled: mask (set to NaN) all input elements that are
      outliers (defined by MAD-clipping). Combined with the stacking
      operators this allows removing large contiguous outliers in your
      final stacked datasets.

    - siglclip-maskfilled: similar to 'madclip-maskfilled', but defining
      outliers by Sigma-clipping.

    - zeropoint-change: change the zero point of the input data set to a
      new zero point.

*** Statistics

  --concentration: measure the "concentration" of values in a distribution
    around the median. See the book for the full description of this
    option.

*** astscript-fits-view
  --globalhdu: use the same HDU in any number of input files (with the
    short format of '-g'); similar to the same option in Arithmetic or
    ConvertType.

  --ds9region: load any number of DS9 region files (separated by comas and
    given to this option) into the DS9 window that will be opened. This was
    added by Giacomo Lorenzetti.

  - The default DS9 'sls' colormap contrast and bias are adjusted so the
    largest value does not have a white color, but is dark red. This was
    done because white is DS9's default color for blank pixels and
    out-of-image regions; making the pixels with the largest value
    invisible.

*** astscript-radial-profile
  --polar: generate a 2D polar plot in the same region of the image that
    the 1D radial profile has been calculate over. The polar plot is a
    mapping/projection of pixels into an azimuthal angle vs. radius grid,
    highlighting features that have polar symmetry (for example spiral arms
    in galaxies or diffraction spikes in the PSF). This feature was
    implemented by Sepideh Eskdandarlou.

*** astscript-psf-scale-factor
  --nocentering: disable sub-pixel centering of the desired star before
    finding the scale factor; added by Sepideh Eskandarlou and Raul
    Infante-Sainz.

*** Makefile extensions
  - $(ast-text-prev TARGET, LIST): select the word that is previous to
    'TARGET' in a list of words. See the minimal working example in the
    book for more.

  - $(ast-text-prev-batch TARGET, NUM, LIST): select the previous "batch"
    of 'NUM' words (in relation to the batch that contains 'TARGET'). This
    is useful for steps in your pipelines were you need to limit the
    parallelization to batches. See the minimal working example in the book
    for more.

  - $(ast-text-prev-batch-by-ram TARGET, NEEDED_RAM_GB, LIST): select the
    previous batch of words in 'LIST' such that the total consumed RAM by
    all the parallel executions does not exceed the available RAM when Make
    starts. Like 'ast-text-prev-batch', this is useful for steps in a
    pipeline that require a large amount of RAM (thus not allowing parallel
    execution), but this is more generic and adapts to different systems
    with very different RAM and/or CPU threads. See the minimal working
    example in the book for more.

*** Library

  - gal_statistics_concentration: measure the concentration of values
    around the median; see the book for the details.

  - gal_units_jy_to_wavelength_flux_density: convert Janskys to wavelength
    flux density.

  - gal_units_zeropoint_change: change the zero point of the input data set
    to an output zero point.

** Removed features
** Changed features
*** All programs
  - System configuration files are installed in 'PREFIX/etc/gnuastro/',
    ('PREFIX/' is the installation directory of Gnuastro; when installing
    from source, and if no '--prefix' is given to the './configure script,
    it is '/usr/local'). Until now, the configuration files of Gnuastro's
    programs were installed in 'PREFIX/etc/'. But that was a top-level
    directory for the configuration files of all the programs within the
    operating system. Therefore the old method would unnecessarily populate
    that already crowded directory, and finding Gnuastro's configuration
    files could become non-trivial. This was suggested by Phil Wyett.

  - User configuration files are installed in '$HOME/.local/etc/gnuastro/'
    instead of '$HOME/.local/etc/'. See the description of system
    configuration files above for more.

*** Arithmetic

  - The following operators will output two operands: the main statistic
    and the number of inputs used in each pixel: 'sigclip-mean',
    'sigclip-median', 'sigclip-std', 'sigclip-mad', 'madclip-mean',
    'madclip-median', 'madclip-std', 'madclip-mad'. See the book for full
    examples on how to work with this (in summary: use '--writeall' to also
    write the numbers image in the output or use 'swap free' to free it).

  - Removed operators:

    - 'madclip-number' and 'sigclip-number': because the numbers image will be
      returned with any clipping stacking operator.

    - 'madclip-fill-mad', 'sigclip-fill-mad', 'madclip-fill-std',
      'sigclip-fill-std', 'madclip-fill-mean', 'sigclip-fill-mean',
      'madclip-fill-median', 'sigclip-fill-median', 'madclip-fill-std',
      'sigclip-fill-std': because the newly added and more general
      operators ('madclip-maskfilled' and 'sigclip-maskfilled') can be
      combined with any of the stacking operators to produce these as well
      as many other useful scenarios.


*** ConvertType

  - Standard input (stdin) is only checked when no input file has been
    specified. Until now, the 'stdin' would be checked all the time, and if
    anything was present there, it would be taken as the first color
    channel. But this could cause problems in shell loops that parse the
    standard input (for example, see
    https://lists.gnu.org/archive/html/help-bash/2024-02/msg00074.html). Also,
    it would rarely happen that when the three RGB color channels are
    necessary, the first would be from the standard input, and the other
    two as files. The new behavior is much more similar to the behavior of
    other command-line programs like AWK or SED. This issue was reported by
    Jesús Vega and Raul Infante-Sainz and solved with the help of Greg
    Wooledge and Dennis Williamson.

*** CosmicCalculator

  - The names of spectral lines which include their rest frame wavelength
    is rounded to the nearest integer. For example the OIII line at
    wavelength of 5006.84 Angstroms is now called O-III-5007. Until now,it
    was confusingly/wrongly called O-III-5006!

*** Library

  - speclines.h: macros specifying spectral lines have been corrected to
    round wavelengths to nearest integer (see description of changes in
    CosmicCalculator). For example the old 'GAL_SPECLINES_O_III_5006' is
    now called 'GAL_SPECLINES_O_III_5007'.

*** astscript-fits-view
  - The short format of the '--ds9geometry' option is '-G' (until now it
    was '-g'). This was necessary to allow the '-g' of this script to have
    a similar behavior to the other Gnuastro programs that take multiple
    inputs (like Arithmetic or ConvertType) and '-g' is short for
    '--globalhdu' (so the same HDU is opened in all the inputs).

** Bugs fixed
  - bug #65255: description of CosmicCalculator's '--arcsectandist' didn't
    specify if it is in physical or comoving coordinates. Found and fixed
    by Boud Roukema.

  - bug #65267: 'astscript-fits-view' created incorrect call to ds9 when
    the number of input files was more than the specified HDUs.

  - bug #65269: 'astscript-color-faint-gray' and 'astscript-psf-stamp' use
    a coma as the decimal point on some operating systems. Reported by
    Jesús Vega and fixed by Raul Infante-Sainz.

  - bug #65377: MakeCatalog's suggested command when labeled image has
    negative values (and MakeCatalog crashes) is wrong. Reported by Zahra
    Sharbaf.

  - bug #65382: Radial profile script truncates the azimuthal angle when
    the maximum requested azimuthal range is above 360 degrees. Reported by
    Fernando Buitrago Alonso and fixed by Raul Infante-Sainz.

  - bug #63064: Statistics crashes when all pixels are NaN. Reported by
    Raul Infante-Sainz and fixed with help of Thorsten Alteholz.

  - bug #65494: Crop segmentation fault with older CFITSIOs (three word
    version format). Reported by Giacomo Lorenzetti.

  - bug #65571: Crop returns successfully when no output was made. Reported
    by Sepideh Eskandarlou.

  - bug #65561: Projections to infinity cause very long running time in
    Warp. Found and fixed by Giacomo Lorenzetti.

  - bug #63026: Warp translation adds one extra pixel even if it is not
    requested. Reported by Raul Infante-Sainz and fixed by Giacomo
    Lorenzetti.

  - bug #65672: ./developer-build exits silently when some options are
    given an empty value. Found and fixed by Giacomo Lorenzetti.

  - bug #65673: Arithmetic creates a metadata FITS file a HDU with no data)
    even when the output is not FITS (plain-text or on the standard
    output). Reported by Sepideh Eskandarlou.

  - bug #65743: Arithmetic's collapse-number mistakenly calculating
    collapse-median instead. Reported by Sepideh Eskandarlou.

  - bug #65801: astscript-fits-view could not properly parse the short
    versions of the '--ds9geometry', '--ds9extra', '--ds9center' and
    '--ds9mode' when the value was touching the short option name. Found
    and fixed by Giacomo Lorenzetti.

  - bug #65822: MakeProfiles does not write negative values with --replace.

  - bug #65833: Convolve crashes when the kernel only has a single element.

  - bug #65847: make check FAILs on color-faint-gray script when libjpeg
    not found. Reported by Takashi Ichikawa.

  - bug #65853: Statistics crashes with the --ontile option.

  - bug #65862: Output directory ignored when Statistics is called with
    the '--ontile' option.

  - bug #65935: Arithmetic crashes with constants like speed of light.

  - bug #65939: Column numbers in plain-text table metadata with +100
    columns incorrectly written for the first 9 (single-digit) columns;
    found with the help of Sepideh Eskandarlou.

  - bug #65941: Name of spectral lines with wavelength were not rounded to
    smallest nearest integer (see description of change in
    CosmicCalculator).





* Noteworthy changes in release 0.22 (library 20.0.0) (2024-02-03)
** New publications
  - https://ui.adsabs.harvard.edu/abs/2023RNAAS...7..269E by Eskandarlou et
    al. on Gnuastro's zero point measurement script for calibration of
    astronomical images ('astscript-zeropoint').
  - https://ui.adsabs.harvard.edu/abs/2024RNAAS...8...10I by Infante-Sainz
    & Akhlaghi on Gnuastro's script to visualize the full dynamic range of
    astronomical images ('astscript-color-faint-gray').
  - https://ui.adsabs.harvard.edu/abs/2024RNAAS...8...22I by Infante-Sainz
    et al. on Gnuastro's script to measure the radial profile of a given
    source ('astscript-radial-profile').

** New features
*** New program
  - 'astscript-color-faint-gray': a new installed script to maximize the
    visualization of the contents within your astronomical images. It does
    this by showing the brighter parts of the image as color, intermediate
    regions as black and the noisy/faint regions as gray/white.

*** All programs
  - The following options are now available in all programs to allow
    customization of which metadata is printed in the 0-th HDU of the FITS
    output of all Gnuastro programs. Also see the "Changed features" list
    for an important change in this regard to all Gnuastro output FITS
    files.
    --outfitsnoconfig: do not print any metadata in the 0-th HDU (including
      the used options and their values, the date, the versions and git
      commit of running directory).
    --outfitsnodate: do not write the 'DATE' keyword.
    --outfitsnoversions: do not write the versions of Gnuastro and
      mandatory dependencies.
    --outfitsnocommit: do not write the Git commit.

*** Arithmetic
  --arguments: takes the name of plain-text file that contains the list of
    arguments to the program. This option is critical if you have very long
    (thousands) of operands and operators (which happen in large pipelines
    where the arguments are constructed automatically). Without this
    option, the shell is going to abort with an "Argument list too long"
    error message.
  - New operators:
    - rotate-coord: given a 2D point's coordinates, return the coordinates
      after it has been rotated by your requested angle around your
      requested center (see documentation for example).
    - mad: Median Absolute Deviation (MAD) stacking.
    - madclip-mad: MAD after MAD-clipping stacking.
    - madclip-std: Standard deviation after MAD-clipping stacking.
    - madclip-mean: Mean after MAD-clipping stacking.
    - madclip-median: Median after MAD-clipping stacking.
    - madclip-number: Number of elements after MAD-clipping stacking.
    - madclip-fill-mad: MAD after filled MAD-clipping stacking: this
                        involves a two-phase clipping: after the first
                        clipping, Arithmetic will "fill" the unclipped
                        holes in each input and masks them for a second
                        round. This is critical for clipping more
                        diffuse outliers: where a pixel may not be
                        clipped individually and will produce biased
                        results, but due to proximity with many nearby
                        clipped pixels, it can be discarded and thus its
                        effect on the final stack be removed.
    - madclip-fill-std: Standard deviation after filled MAD-clipping stacking.
    - madclip-fill-mean: Mean after filled MAD-clipping stacking.
    - madclip-fill-median: Median after filled MAD-clipping stacking.
    - madclip-fill-number: Num. of elements after filled MAD-clipping stacking.
    - sigclip-fill-mad: MAD after filled MAD-clipping stacking.
    - sigclip-fill-std: Standard deviation after filled MAD-clipping stacking.
    - sigclip-fill-mean: Mean after filled MAD-clipping stacking.
    - sigclip-fill-median: Median after filled MAD-clipping stacking.
    - sigclip-fill-number: Num. of elements after filled MAD-clipping stacking.
    - sigclip-mad: MAD after sigma-clipping stacking.
    - collapse-madclip-mad: Collapse dim. by MAD-clipped MAD.
    - collapse-madclip-std: Collapse dim. by MAD-clipped STD.
    - collapse-madclip-mean: Collapse dim. by MAD-clipped mean.
    - collapse-madclip-median: Collapse dim. by MAD-clipped median.
    - collapse-madclip-number: Collapse dim. by MAD-clipped number.
    - collapse-madclip-fill-mad: Collapse dim. by filled MAD-clipped MAD.
    - collapse-madclip-fill-std: Collapse dim. by filled MAD-clipped STD.
    - collapse-madclip-fill-mean: Collapse dim. by filled MAD-clipped mean.
    - collapse-madclip-fill-median: Collapse dim. by filled MAD-clipped median.
    - collapse-madclip-fill-number: Collapse dim. by filled MAD-clipped num.
    - collapse-sigclip-mad: Collapse dim. by sigma-clipped MAD.
    - collapse-sigclip-fill-mad: Collapse dim. by filled sigma-clipped MAD.
    - collapse-sigclip-fill-std: Collapse dim. by filled sigma-clipped STD.
    - collapse-sigclip-fill-mean: Collapse dim. by filled sigma-clipped mean.
    - collapse-sigclip-fill-median: Collapse dim. by filled sigma-clip. median.
    - collapse-sigclip-fill-number: Collapse dim. by filled sigma-clipped num.

*** Fits
  --arguments: takes the name of plain-text file that contains the list of
    arguments to the program. Currently this only works with '--keyvalue'
    and is necessary when you want to get the keywords of a very long list
    of files (~thousands!). Without this option, the shell is going to
    abort with an "Argument list too long" error message.
  --datasum-encoded: new option that will return an ASCII encoded
    16-character string for the value of the 'DATASUM' concept in FITS data
    verification.

*** Statistics
  --checkskynointerp: similar to '--checksky', but stop as soon as the good
    tiles are found (do not continue to interpolation and smoothing of the
    tiles which can be time consuming if not needed).
  --mad: Median Absolute Deviation (MAD) of input dataset.
  --madclip: MAD-clipping, showing intermediate results.
  --sigclip-mad: MAD of input after sigma-clipping.
  --madclip-number: Number of input elements after MAD-clipping.
  --madclip-median: Median of input elements after MAD-clipping.
  --madclip-mean: Mean of input elements after MAD-clipping.
  --madclip-std: Standard deviation of input elements after MAD-clipping.
  --madclip-mad: MAD of input elements after MAD-clipping.
  --mclipparams: Parameters of MAD-clipping, similar to sigma-clipping. Note
                 that in a Gaussian distribution, MAD = 0.67 sigma, so if
                 you want something similar to 3-sigma (the default), you
                 should set the MAD multiple to 5 (the default).

*** Makefile extension
  - 'ast-text-to-upper': convert input string to upper-case.
  - 'ast-text-to-lower': convert input string to lower-case.
*** Library
**** Functions
  - gal_dimension_collapse_mclip_mad: MAD-clipped MAD.
  - gal_dimension_collapse_mclip_fill_mad: filled MAD-clipped MAD.
  - gal_dimension_collapse_mclip_std: MAD-clipped STD.
  - gal_dimension_collapse_mclip_fill_std: filled MAD-clipped STD.
  - gal_dimension_collapse_mclip_mean: MAD-clipped mean.
  - gal_dimension_collapse_mclip_fill_mean: filled MAD-clipped mean
  - gal_dimension_collapse_mclip_median: MAD-clipped median.
  - gal_dimension_collapse_mclip_fill_median: filled MAD-clipped median.
  - gal_dimension_collapse_mclip_number: MAD-clipped number.
  - gal_dimension_collapse_mclip_fill_number: filled MAD-clipped number.
  - gal_dimension_collapse_sclip_mad: sigma-clipped MAD
  - gal_dimension_collapse_sclip_fill_mad: filled sigma-clipped MAD.
  - gal_dimension_collapse_sclip_fill_std: filled sigma-clipped STD.
  - gal_dimension_collapse_sclip_fill_mean: filled sigma-clipped mean
  - gal_dimension_collapse_sclip_fill_median: filled sigma-clipped median.
  - gal_dimension_collapse_sclip_fill_number: filled sigma-clipped number.
  - gal_fits_hdu_datasum_encoded: the 16-character encoded sting datasum.
  - gal_fits_key_list_add_date: add 'DATE' to current list of keywords.
  - gal_fits_key_list_add_git_commit: add the Git commit information of the
    running directory to the input list of keywords (if built with libgit2).
  - gal_fits_key_list_add_software_versions: add versions of Gnustro and
    its mandatory dependencies to the input list of keywords.
  - gal_statistics_clip_mad: MAD clipping of given input.
  - gal_statistics_mad: return median absolute deviation (MAD).
  - gal_statistics_median_mad: return median and MAD.
  - gal_txt_read_to_list: read all the space-separated words of the input
    plain-text file as a separate node in a linked list of strings.

**** Macros
  - Used by 'gal_arithmetic':
    - GAL_ARITHMETIC_OP_SIGCLIP_MAD: Sigma-clipped MAD.
    - GAL_ARITHMETIC_OP_SIGCLIP_MAD: Sigma-clipped STD.
    - GAL_ARITHMETIC_OP_SIGCLIP_FILL_NUMBER: MAD-clipped num. of arrays.
    - GAL_ARITHMETIC_OP_SIGCLIP_FILL_MEAN: MAD-clipped mean of arrays.
    - GAL_ARITHMETIC_OP_SIGCLIP_FILL_MEDIAN: MAD-clipped median of arrays.
    - GAL_ARITHMETIC_OP_SIGCLIP_FILL_STD: MAD-clipped STD of arrays.
    - GAL_ARITHMETIC_OP_SIGCLIP_FILL_MAD: MAD-clipped STD of arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_NUMBER: MAD-clipped number of mult. arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_MEAN: MAD-clipped mean of multiple arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_MEDIAN: MAD-clipped median of mult. arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_STD: MAD-clipped STD of multiple arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_MAD: MAD-clipped STD of multiple arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_FILL_NUMBER: MAD-clipped num. of arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_FILL_MEAN: MAD-clipped mean of arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_FILL_MEDIAN: MAD-clipped median of arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_FILL_STD: MAD-clipped STD of arrays.
    - GAL_ARITHMETIC_OP_MADCLIP_FILL_MAD: MAD-clipped STD of arrays.
  - Used by 'gal_statistics_clip_sigma' and 'gal_statistics_clip_mad':
    - GAL_STATISTICS_CLIP_OUTCOL_NUMBER_USED: index of final number in output.
    - GAL_STATISTICS_CLIP_OUTCOL_MEAN: index of clipped mean in output.
    - GAL_STATISTICS_CLIP_OUTCOL_STD: index of clipped STD in output.
    - GAL_STATISTICS_CLIP_OUTCOL_MEDIAN: index of clipped median in output.
    - GAL_STATISTICS_CLIP_OUTCOL_MAD: index of clipped MAD in output.
    - GAL_STATISTICS_CLIP_OUTCOL_NUMBER_CLIPS: index of clipped number in output.
    - GAL_STATISTICS_CLIP_OUTCOL_OPTIONAL_MEAN: bit flag for measuring mean.
    - GAL_STATISTICS_CLIP_OUTCOL_OPTIONAL_STD: bit flag for measuring STD.
    - GAL_STATISTICS_CLIP_OUTCOL_OPTIONAL_MAD: bit flag for measuring MAD.

** Removed features
*** Library
  - gal_fits_key_write_version: redundant with the new
    'gal_fits_key_list_add_software_versions'.
  - gal_fits_key_write_version_in_ptr: as in gal_fits_key_write_version.
  - gal_fits_key_write_config: redundant since all configuration (options)
    are stored as generic keys.

** Changed features
*** All programs
  - Date and versions FITS keywords are only written in the 0-th HDU of
    output FITS files (along with the options names and values), not the
    HDU(s) containing data. Until now, the data and versions metadata were
    written in the data HDU. However, ultimately, these are also metadata
    and are better suited for the 0-th HDU. For example when everything
    else is identical, you expect an exactly reproducible HDU (to verify
    with the FITS 'CHECKSUM' for example), but every time you run, 'DATE'
    will be different! Similarly for the versions of the software or Git
    commit (they may change, while your dataset doesn't). To disable these
    in the 0-th HDU also, see the newly added '--outfitsno*' options in the
    new features.

*** Arithmetic
  - Binary operators (like '+' or 'x') that are given two integers will
    crash with an error if the input operands have the same width but
    different signs. Until now, they would just report a warning and print
    the output. However, in large scripts, users could miss the warning and
    not be aware of a possibly wrong result. Therefore it is more robust to
    crash with an error rather than print a warning. This was suggested by
    Sepideh Eskandarlou and implemented by Faezeh Bidjarchian after a poll
    on Gnuastro's Matrix chat channel (#gnuastro:openastronomy.org).

*** CosmicCalculator
  - In a non-FLRW model (when the sum of the densities is not 1.0),
    CosmicCalculator no longer crashes with an error since calculations
    like the radial comoving distance ('--properdistance') are still valid
    in a curved cosmology. Instead a warning is printed informing the user
    that with Gnuastro's current implementation angular diameter based
    calculations will be wrong. This was implemented by Boud Roukema.
  --angulardiamdist is the new name for the old '--angulardimdist'
    option. This was necessary to avoid confusion of 'dim' in the old name
    with "dimension"; 'diam' makes it clear that this is a "diameter", not
    'dimension'. This was suggested by Boud Roukema.

*** Crop
  - The 'ICF*' keywords are now written in the 0-th HDU of Crop's outputs
    (the extension with no data, only metadata). Therefore, the WCS is now
    the only metadata in the HDU containing data.

*** astscript-psf-stamp
  - When no name is given to the temporary directory, the default name will
    contain the center coordinates as a suffix (to avoid being confused
    with other calls for other centers), and the contents of the temporary
    directy will have the same filename. Until now, the temporary directory
    name would be the same for different calls, and the coordinates suffix
    would be in the temporary file names. This could cause confusions and
    bugs (for example one call to this script could delete the temporary
    directory that was being used by a later call).

*** Library
  - gal_cosmology_age: a 'quiet' argument is added to disable warnings.
  - gal_cosmology_proper_distance: similar 'gal_cosmology_age'.
  - gal_cosmology_comoving_volume: similar 'gal_cosmology_age'.
  - gal_cosmology_critical_density: similar 'gal_cosmology_age'.
  - gal_cosmology_angular_distance: similar 'gal_cosmology_age'.
  - gal_cosmology_luminosity_distance: similar 'gal_cosmology_age'.
  - gal_cosmology_distance_modulus: similar 'gal_cosmology_age'.
  - gal_cosmology_to_absolute_mag: similar 'gal_cosmology_age'.
  - gal_fits_key_write: to generalize, the "title" argument has been
    removed (because it is a keyword). It can also create the file if it
    doesn't exist and can optionally free the list of keywords (until now,
    it would always free them).
  - gal_fits_key_write_in_ptr: similar to 'gal_fits_key_write'.
  - gal_fits_img_write: no more 'program_name'; it is a keyword title;
    added 'freekeys' argument to optionally free the input keyword list.
  - gal_fits_img_write_to_type: as in 'gal_fits_img_write'.
  - gal_fits_img_write_corr_wcs_str: as in 'gal_fits_img_write'.
  - gal_fits_tab_write: as in 'gal_fits_img_write'.
  - GAL_STATISTICS_CLIP_MAX_CONVERGE: new name for the old
    'GAL_STATISTICS_SIG_CLIP_MAX_CONVERGE'. Since we now also have
    MAD-clipping.
  - gal_statistics_clip_sigma: new name for 'gal_statistics_sigma_clip'.
  - gal_table_write: as in 'gal_fits_img_write'.
  - gal_tile_full_values_write: as in 'gal_fits_img_write'.
  - gal_wcs_write: as in 'gal_fits_img_write'.

** Bugs fixed
  - bug #46225: Programs don't depend on libs in Makefiles; reported by
                Mosè Giordano and fixed by Thorsten Alteholz.
  - bug #52295: Cosmology library integrals crash for high z; fixed by
                Thorsten Alteholz.
  - bug #52674: Correcting Clang warnings on macOS during compilation;
                fixed with help of Thorsten Alteholz and Raul
                Infante-Sainz.
  - bug #61476: astscript-ds9-region: output created when input file does
                not exist; reported by Sepideh Eskandarlou, fixed by
                Thorsten Alteholz.
  - bug #64825: astscript-fits-view only takes the last HDU provided;
                reported by Teet Kuumta and fixed by Raul Infante-Sainz.
  - bug #64852: astscript-zeropoint: crash when input is in 0-th HDU;
                reported in https://savannah.gnu.org/support/?110952; fixed
                by Sepideh Eskandarlou.
  - bug #64915: Segment's SKY_STD output HDU does not have WCS; reported by
                Sepideh Eskandarlou.
  - bug #64952: Table error message for incorrect column name was not
                complete; reported by Sepideh Eskandarlou.
  - bug #65005: astscript-psf-unit not accounting for --innerhdu; reported
                by Ignacio Ruiz Cejudo.
  - bug #65050: Use --libtool option in the TEMPLATE usage; found and fixed
                by Faezeh Bidjarchian.
  - bug #65055: Columns of empty FITS tables (with no rows) read in
                reverse.
  - bug #65084: Fits program's --skycoverage prints connected numbers for
                cubes; found with help of Rahna Payyasseri Thanduparackal.
  - bug #65106: Necessity of --oversample with astscript-radial-profile
                when a 2D profile is to be created with '--customtable' of
                MakeProfile; reported by Sepideh Eskandarlou.
  - bug #65141: MakeCatalog crash when labled image is all blank; reported
                by Sepideh Eskandarlou.
  - bug #65149: MakeCatalog '--frac-max*-*' measurements done without
                '--frac-max'; reported by Helena Domínguez Sánchez.
  - bug #65194: --quiet does not disable the warning for un-given
                minmapsize; reported by Boud Roukema.
  - bug #65195: CosmicCalculator prevents non-flat FLRW models and angular
                diameter distance only correct in flat models. Found and
                fixed by Boud Roukema.





* Noteworthy changes in release 0.21 (library 19.0.0) (2023-10-20)
** New features
*** New program
  - 'astscript-pointing-simulate': a new installed script that will
    simplify the process of designing a pointing pattern for your observing
    strategy. It takes into account the distortion of the camera, runs in
    parallel and allows customizations (for example to account for
    vignetting, or large blobs of bad pixels) through hooks at relevant
    steps. A new tutorial has been added in the Tutorials chapter of the
    book on how to use this new script. The following research note has
    also been published for this script:
    https://ui.adsabs.harvard.edu/abs/2023RNAAS...7..211A

*** Book
  - New tutorial on a low surface brightness optimized design of a pointing
    pattern using the newly added installed script in Gnuastro for
    simulating the exposure map of a pointing pattern stack (it is called as
    'astscript-pointing-simulate' on the command-line).
  - Smaller tutorials that were distributed within the documentation of
    different programs are brought into the "Tutorials" chapter.
  - New "Standard deviation vs. error" sub-section added under the
    MakeCatalog section. It uses real examples to clearly show the
    fundamental difference between the two (which are sometimes confused
    with each other). This was written with the help of Raul Infante-Sainz.

*** Configuration files
  - To separate the option name and value, you can now also use the '='
    character. This allows your custom configuration files to also be
    loaded into a shell (with 'source') or Make (with 'include'). Until
    now, only white-space characters were allowed as separators of option
    names and values.
  --config-prefix=STR: Given string can be a prefix of options in
    configuration files. Added with the point above, this allows loading
    the different configuration files of different instances of the same
    program without overwriting them. See the example in the book.

*** Arithmetic
  - New operators (see book for a full description):
    - pool-min: Min-pooling to reduce the size of the input by calculating
                the minimum of a the pixels within the pooling window
                (accounting for a stride). See the new "Pooling operators"
                section of the book for more. The pooling operators were
                all implemented by Faezeh Bidjarchian.
    - pool-max: Similar to 'pool-min' but using maximum.
    - pool-sum: Similar to 'pool-min' but using sum.
    - pool-mean: Similar to 'pool-min' but using mean.
    - pool-median: Similar to 'pool-min' but using median.
    - to-1d: convert the input operand into a 1D array, no matter how many
             dimensions it has. Suggested by Faezeh Bidjarchian.
    - trim: remove all fully-blank outer regions of the input dataset.
    - eq-b1950-to-eq-j2000: Convert input equatorial coordinates (RA and
                            Dec) in the B1950 equinox to equatorial J2000
                            equinox.
    - eq-b1950-to-ec-b1950: Same input as above; to ecliptic B1950.
    - eq-b1950-to-ec-j2000: Same input as above; to ecliptic J2000.
    - eq-b1950-to-galactic: Same input as above; to Galactic.
    - eq-b1950-to-supergalactic: Same input as above; to Supergalactic.
    - eq-j2000-to-eq-b1950: Convert input equatorial coordinates (RA and
                            Dec) in the J2000 equinox to equatorial B1950
                            equinox.
    - eq-j2000-to-ec-b1950: Same input as above; to ecliptic B1950.
    - eq-j2000-to-ec-j2000: Same input as above; to ecliptic J2000.
    - eq-j2000-to-galactic: Same input as above; to Galactic.
    - eq-j2000-to-supergalactic: Same input as above; to Supergalactic.
    - ec-b1950-to-eq-b1950: Convert input ecliptic coordinates in the
                            B1950 equinox to equatorial B1950 equinox.
    - ec-b1950-to-eq-j2000: Same input as above; to equatorial B1950.
    - ec-b1950-to-ec-j2000: Same input as above; to ecliptic J2000.
    - ec-b1950-to-galactic: Same input as above; to Galactic.
    - ec-b1950-to-supergalactic: Same input as above; to Supergalactic
    - ec-j2000-to-eq-b1950: Convert input ecliptic coordinates in the
                            J2000 equinox to equatorial B1950 equinox.
    - ec-j2000-to-eq-j2000: Same input as above; to equatorial J2000.
    - ec-j2000-to-ec-b1950: Same input as above; to ecliptic B1950.
    - ec-j2000-to-galactic: Same input as above; to Galactic.
    - ec-j2000-to-supergalactic: Same input as above; to Supergalactic.
    - galactic-to-eq-b1950: Convert input Galactic coordinates to
                            equatorial B1950 equinox.
    - galactic-to-eq-j2000: Same input as above; to equatorial J2000.
    - galactic-to-ec-b1950: Same input as above; to ecliptic B1950.
    - galactic-to-ec-j2000: Same input as above; to ecliptic J2000.
    - galactic-to-supergalactic: Same input as above; to Supergalactic.
    - supergalactic-to-eq-b1950: Convert input Supergalactic coordinates to
                                 equatorial B1950 equinox.
    - supergalactic-to-eq-j2000: Same input as above; to equatorial J2000.
    - supergalactic-to-ec-b1950: Same input as above; to ecliptic B1950.
    - supergalactic-to-ec-j2000: Same input as above; to ecliptic J2000.
    - supergalactic-to-galactic: Same input as above; to Galactic.

*** ConvertType
  - It is now possible to write TIFF files in the output (until now,
    Gnuastro could only read TIFF files). This step was written by Fathma
    Mehnoor.

*** Convolve
  --conv-on-blank: do not ignore blank pixels in the convolution. This will
    effectively expand the non-blank regions of your dataset into the blank
    regions and only works in spatial-domain convolution. This was
    suggested by Raul Infante-Sainz.

*** MakeCatalog
  - New measurements:
    --river-min: minimum river value around a clump.
    --river-max: minimum river value around a clump.

*** Table
  --info-num-cols: print the number of the input table's columns and abort.
  --info-num-rows: print the number of the input table's rows and abort.
  - '$_all' in column arithmetic: when an arithmetic expression contains
    this string, it will be repeated independently for all the columns of
    the input table.
  - New operators in Table's column arithmetic:
    - eq-j2000-to-flat: convert the RA and Dec columns in a table to a
      flat-RA and flat-Dec (accounting for a reference point as well as any
      type of projection that is available in the FITS WCS standard). This
      is necessary when you are plotting points in a report or paper cover
      more than a couple of square degrees on the sky. Without this
      operator, significant distortions will appear when you plot spherical
      coordinates (RA,Dec) on a flat plane (your paper's plot). See the
      documentation for this operator in the book for more.
    - eq-j2000-from-flat: the inverse of 'eq-j2000-to-flat' (useful when
      designin dither patterns for example (where you know the final
      shape/distanced after flatting; and want coordinates on the sphere).

*** astscript-zeropoint
  --mksrc: use a custom Makefile for estimating the zeropoint, not the
    default installed Makefile. This is primarily intended for debugging or
    developing this script, not for normal usage.

*** Library
  - gal_blank_not_minmax_coords: returns the minimum/maximum coordinates of
    non-blank regions of input dataset.
  - gal_blank_trim: trim all outer blank regions from the input dataset.
  - gal_polygon_area_sky: area of polygon defined on celestial coordinates.
  - gal_pool_min: min-pooling function, see 'pool-min' above.
  - gal_pool_max: max-pooling function, see 'pool-min' above.
  - gal_pool_sum: sum-pooling function, see 'pool-min' above.
  - gal_pool_mean: mean-pooling function, see 'pool-min' above.
  - gal_pool_median: median-pooling function, see 'pool-min' above.
  - gal_statistics_mad: Calculate the Median Absolute Deviation (MAD).
  - gal_statistics_median_mad: Calculate the Median and MAD.
  - gal_statistics_clip_mad: Median Absolute Deviation (MAD) clipping.
  - gal_tiff_write: write 'gal_data_t' to a TIFF file; written by
    Fathma Mehnoor.
  - gal_wcs_projection_name_to_id: convert projection names to IDs.
  - gal_wcs_projection_name_from_id: convert projection IDs to their name.
  - gal_wcs_coordsys_convert_points: convert the input set of points from
    one celestial coordinate system to another.
  - gal_wcs_coordsys_sys1_ref_in_sys2: return the longitude reference point
    of the first celestial coordinate system in the second coordinate
    system's longitude and latitude.

** Removed features
*** MakeNoise
    - MakeNoise (with executable name 'astmknoise') has been removed from
      Gnuastro. This is because the 'mknoise-*' operators of Arithmetic do
      the same job, but in a much more customizable, modular and manageable
      manner; allowing to mix with other operators. The "Noise basics"
      sub-section of the book has been moved under the Arithmetic program's
      documentation also.

** Changed features
*** Arithmetic
    - mknoise-sigma-from-mean: new name for the old 'mknoise-poisson'
      random number distribution.
    - mknoise-poisson: now produces correct Poisson distribution output,
      which can be non-symmetric in low background values and is always
      integers. For a complete description and hands-on example of the
      differences with 'mknoise-sigma-from-mean' and 'mknoise-sigma', see
      the description of these three operators in the "Random number
      generators" operators sub-section of the "Arithmetic operators"
      section of the Gnuastro book.

*** MakeCatalog
  - The dash in the column names of the following measurement names has
    been replaced by underscore to conform with the general standard of
    using underscores between words in column names (reported by Raul
    Infante-Sainz). Also, in the case of '--sigclip-mean-sb-delta' the
    column name didn't correspond to the option name.
    --------------------------------------------------------------
    Option                  Column name            Old column name
    --------------------------------------------------------------
    --sigclip-mean          SIGCLIP_MEAN           SIGCLIP-MEAN
    --sigclip-median        SIGCLIP_MEDIAN         SIGCLIP-MEDIAN
    --sigclip-number        SIGCLIP_NUMBER         SIGCLIP-NUMBER
    --sigclip-std           SIGCLIP_STD            SIGCLIP-STD
    --sigclip-mean-sb       SIGCLIP_MEAN_SB        SIGCLIP-MEAN-SB
    --sigclip-mean-sb-delta SIGCLIP_MEAN_SB_DELTA  SIGCLIP-MEAN-SB-ERR
    --------------------------------------------------------------
  - The default extension name for the values image ('--valueshdu') is now
    'INPUT-NO-SKY'. Until now, it was simply '1' (without any hint on what
    what is expected by default). Recall that if the sky is not subtracted
    from the values image you can use '--sky' for MakeCatalog to subtract
    it before the measurements. Implemented by Sepideh Eskandarlou.
  - When the input clump labels do not have the 'NUMLABS' keyword
    (specifying how many clumps there are in the image, independent of the
    number of objects), MakeCatalog will no longer re-label the input
    clumps: the output catalog will have the same clump ids as the
    labels. Until now, it would generate new labels for the clumps in such
    cases (along with a new FITS image containing the clumps with the new
    labels to allow you to match them). The output catalog also had the new
    label, not the original labels (the old behavior was therefore very
    inconvenient!).

*** Segment
  - The default name of the first extension of Segment's output is now
    'INPUT-NO-SKY', until now, it was 'INPUT'. This was necessary because
    the first extension of the output is not the exact input file (if a
    value is given to '--sky' it will be subtracted from the input in the
    first extension). Implemented by Sepideh Eskandarlou.

*** astscript-psf-stamp
  - After applying the signal-to-noise threshold (if it is requested), any
    extra pixels that are not connected to the central target are also
    masked. Such pixels can remain in rivers between bright clumps and
    would cause problem in the final stack and were not removed until now.
    Implemented by Sepideh Eskandarlou

*** Library
  - gal_convolve_spatial: new argument to allow convolution over blank
    elements.
  - gal_convolve_spatial_correct_ch_edge: new argument to allow convolution
    over blank elements.
  - gal_polygon_area_flat: new name for the old 'gal_polygon_area'
    function. This was necessary because this function assumes flat
    coordinates and can lead to wrong results when used with a polygon
    defined by RA,Dec for example.
  - gal_statistics_clip_sigma: new name for 'gal_statistics_sigma_clip',
    also, a new argument has been added to measure statistics that were not
    automatically calculated during the clipping.
  - gal_wcs_distortion_name_to_id: new name of gal_wcs_distortion_from_string.
  - gal_wcs_distortion_name_from_id: new name of gal_wcs_distortion_to_string.
  - gal_wcs_coordsys_name_to_id: new name of gal_wcs_coordsys_from_string.

** Bugs fixed
  bug #64138: Arithmetic's mknoise-poisson only using first pixel value.
              Reported by Irene Pintos Castro.
  bug #64146: SIGCLIP column names contain dashes instead of
              underlines. Reported by Raul Infante-Sainz.
  bug #64148: MakeCatalog crash when using the options '--std' and/or
              'sigclip-mean-sb-delta' for clumps catalog. Reported by Raul
              Infante-Sainz.
  bug #64153: astscript-ds9-region: '--namecol' gives a constant zero in
              image-mode. Reported by Zahra Sharbaf.
  bug #64186: Query: core dump when custom name given to '--dataset'. First
              reported by Zohreh Ghaffari as a problem in
              'astscript-select-stars' (sr #110874) and identified as a
              problem in Query by Sepideh Eskandarlou.
  bug #64199: info astscript-zeropoint not working. Reported by Zahra
              Sharbaf.
  bug #64246: Query's --information gives a crash for Gaia datasets.
              Reported by Rashid Yaaqib.
  bug #64250: astscript-fits-view: no message printed when input file did
              not exist. Reported by Ryan Begley.
  bug #64274: MakeProfiles crash for points in 3D. Found by Teet Kuumta.
  bug #64303: Statistics fit --fitestimate crash when covariance matrix has
              NaN. Reported Sepideh Eskandarlou.
  bug #64357: Plain text metadata ignored when no name is present.
  bug #64392: Arithmetic's isnotblank operator producing zeros when no
              blanks present.
  bug #64420: Error message of wrongly specified HDU doesn't give the
              problematic option name; reported by Aaron Watkins.
  bug #64431: gal_wcs_to_cd does not account for altlin==3. Reported by
              Colin Orion Chandler.
  bug #64541: Segment's --keepmaxnearriver has no effect.
  bug #64544: Arithmetic crashes with tofilefree operator value has a
              directory.
  bug #64545: Accounting for CFITSIO silently appending '.gz' when file
              doesn't exist. Reported by Sepideh Eskandarlou.
  bug #64610: --copykeys of Fits program finds wrong key when the first
              characters of the keyword names match.
  bug #64615: Fits program's '--pixelareaonwcs' only accurate on equator.
  bug #64635: astscript-psf-stamp's '--snthresh' option produces fully NaN
              valued image when a saturated star is in the center. Found
              and fixed by Sepideh Eskandarlou.
  bug #64643: MakeCatalog not reporting the actual '--upmaskhdu' that was
              used on standard output. Found by S. Zahra Hosseini
              Shahisavandi.





* Noteworthy changes in release 0.20 (library 18.0.0) (2023-04-29)
** New features
*** New program
   - astscript-zeropoint: this script is used for calibrating the pixel
     values in one image (finding its "zero point") based on a reference
     catalog or (any number of) reference image(s). The script allows for
     checking many apertures in the same command to let you choose the
     best; and will operate in parallel where necessary. The documentation
     of this script contains two tutorials on how to optimally use it and
     interpret its results; please read and run them once before using it.
     This script was written as a team effort lead by Sepideh Eskandarlou
     and including (in alphabetical order): Elham Saremi, Giulia Golini,
     Raul Infante-Sainz, Samane Raji, Zahra Sharbaf, Zohreh Ghaffari.

*** Book
   - New tutorial on detection and spectrum extraction from 3D data has
     been added in the "Tutorials" chapter. It uses a MUSE cube and
     demonstrates how to subtract the continuum, run NoiseChisel, Segment
     and MakeCatalog for obtaining spectra and creating pseudo narrow-band
     images of emission-lines.
   - New "Shell tips" sub-section added (under the "Command-line" section
     of the "Common program behavior" chapter). This sub-section contains
     useful shell tips and tricks that can be useful when using Gnuastro's
     programs.

*** Arithmetic
   --writeall: Write all datasets on the stack as separate HDUs in the
     output; this is useful in debugging incomplete Arithmetic commands.
   - New operators (also available in Table).
     - isnotblank: same as 'isblank not', but slightly more efficient.
       This was suggested by Sepideh Eskandarlou.
     - swap: swap the top two datasets on the stack of operands.
     - index: return dataset of same size, with pixel values that are
       integers starting from 0 and incrementing one by one. This operator
       doesn't pop the top dataset from the stack, it only adds one (to
       avoid extra RAM usage in most usage scenarios).
     - counter: similar to 'index', but integers start with 1.
     - indexonly: similar to 'index', but pops the top stack dataset.
     - counteronly: similar to 'counter', but pops the top stack dataset.
     - constant: replace all elements of input image or column with the
       given constant value (for example to set all pixels in an image to
       NaN or zero), or to give identifiers to each source catalog when
       adding rows from different catalogs, see the documentation for
       complete examples.
     - counts-to-nanomaggy: convert counts to Nanomaggy (with fixed
       zeropoint of 22.5, used as the pixel units of many surveys like
       SDSS). This was suggested by Giulia Golini.
     - nanomaggy-to-counts: convert nanomaggy to counts. This was suggested
       by Giulia Golini.
     - box-vertices-on-sphere: calculate the RA,Dec of vertices of the four
       vertices of a rectangle from its center and width along RA and
       Dec. This takes into account the curved nature of the coordinate
       system. Added after discussion with Martin Kuemmel.
     - number-neighbors: Return the number of non-zero neighbors of each
       non-zero pixel in a binary image.
   - New operators (only in the Arithmetic program):
     - interpolate-meanngb: interpolate blank values with mean of the
       requested number of nearest neighbors.
   - Alternative (shorter) names for existing operators, added after
     discussion with Samane Raji.
     - u8:  same as 'uint8'   (to convert to unsigned 8-bit integers).
     - i8:  same as 'int8'    (to convert to signed 8-bit integers).
     - u16: same as 'uint16'  (to convert to unsigned 16-bit integers).
     - i16: same as 'int16'   (to convert to signed 16-bit integers).
     - u32: same as 'uint32'  (to convert to unsigned 32-bit integers).
     - i32: same as 'int32'   (to convert to signed 32-bit integers).
     - u64: same as 'uint64'  (to convert to unsigned 64-bit integers).
     - i64: same as 'int64'   (to convert to signed 64-bit integers).
     - f32: same as 'float32' (to convert to 32-bit floating point).
     - f64: same as 'float64' (to convert to 64-bit floating point).

*** CosmicCalculator
   - Spectral line database has been increased to 235 spectral lines in the
     UV and optical (previously only had 41 lines!) from:
     http://astronomy.nmsu.edu/drewski/tableofemissionlines.html
     To see the full list, run 'astcosmiccal --listlines'.
   --lineunit: allows you to specify the units of the displayed spectral
     line wavelengths. Currently, it take four units: 'm', 'micron', 'nm'
     and 'angstrom'. We can add any other unit easily, just let us know.

*** Crop
   --append: if the output file already exists, append the cropped image
     HDU to the already existing HDUs of the file. Without this option, any
     existing HDUs in the output file will be removed (default behavior).
   --metaname: Specify the name of the cropped output HDU (value to the
     'EXTNAME' keyword in FITS).

*** MakeCatalog
   - Book: with the increasing number of possible measurements the
     "MakeCatalog measurements" section of the Gnuastro book has been
     broken into separate sub-section and contextually similar measurements
     are grouped separately there.
   --sigclip-mean-sb: surface brightness (over one pixel's area in
     arcsec^2) of the sigma-clipped mean of the values. This is useful in
     scenarios where you want to compare surface brightness values
     independent of the object's area, and by removing outliers (for
     example in a radial profile). See the description of this option in
     the book for more. This was added after a discussion by Ignacio
     Trujillo and Zahra Sharbaf.
   --sigclip-mean-sb-err: the error in '--sigclip-mean-sb' but using the
     sigma-clipped standard deviation of the values as the error, not the
     standard deviation image.
   --sigclip-std-sb: the surface brightness (over one pixel's area in
     arcsec^2) of the sigma-clipped standard deviation of the values. This
     can be used to find the reliable surface brightness of a radial
     profile for example.
   --sum-in-slice: [3D in; vector out] Sum of values in each slice.
   --sum-err-in-slice: [3D in; vector out] Error in '--suminslice'.
   --area-in-slice: [3D input; vector out] Number of labeled in each slice.
   --sum-proj-in-slice: [3D input; vector out] Sum of projected area
     in each slice.
   --area-proj-in-slice: [3D in; vector out] Number of voxels that are used
     in '--sum-proj-in-slice'.
   --sum-proj-err-in-slice: [3D in; vector out] Error of '--sum-proj-in-slice'.
   --area-other-in-slice: [3D in; vector out] Area of other label in
     projected area on each slice.
   --sum-other-in-slice: [3D in; vector out] Sum of other label in
     projected area on each slice.
   --sum-other-err-in-slice: [3D in; vector out] Area in
     '--sum-other-in-slice'.

*** NoiseChisel
   --outliernumngb: the number of neighboring tiles to reject those that
     have passed (the mean-median quantile difference criteria) because of
     being on the wings of bright stars/galaxies. Until now, this number
     was the same as the number given to '--interpnumngb', but it is
     confusing and can cause problems (because interpolation is done after
     outlier rejection). From this version, '--interpnumngb' is only in
     charge of the number of neighboring tiles for interpolation outliers
     are defined based on the number of tiles given to this
     option. Therefore, if you are not detecting the wings of large
     galaxies, THE BEST solution is most-probably to increase
     '--outliernumngb'. This was done after a discussion with Elham Saremi.

*** Statistics
   --outliernumngb: see description of same option in NoiseChisel.

*** Table
   - Vector columns with multiple values per column are now supported. The
     following features have been added to help working on vector columns:
     - Book: a new "Vector columns" section has been added under the Table
       program which describes the core concepts and usage examples of the
       options below.
     --information: also identifies vector columns (a column with more than
       one value), by placing an '(N)' after the type. Where 'N' is the
       number of elements within the vector.
     --tovector: merge multiple single-valued columns into a new vector
       column.
     --fromvector: extract identified elements/tokens of a vector column to
       separate single-valued columns.
     --keepvectfin: do not delete the input columns to '--tovector' and
       '--fromvector'.
   --rowfirst: do row-based operations before column-based operations (by
     default column-based operations are done first).
   --transpose: column-based operator to transpose vector columns into a
     new table that has the inverse number of rows and columns.
   --txteasy: (or '-Y') when output is a plain-text file or just gets
     printed on standard output (terminal), all floating point columns are
     printed in fixed point notation (as in '123.456') instead of the
     default exponential notation (as in '1.23456e+02'). For 32-bit
     floating points, use a precision of 3 digits and for 64-bit floating
     points use a precision of 6 digits. This can be useful for human
     readability, but be careful with some scenarios (for example
     '1.23e-120', which will show only as '0.0'!). For more, see the
     changes in Table in this version.
   - New column arithmetic operator:
     - sorted-to-interval: return two columns from a single (sorted) input,
       containing the minimum and maximum values of an interval. The
       intervals are defined such that the intervals of every row fully
       cover the full range of values in the given column. This can be
       useful in scenarios where you need to build the inputs of the
       '--customtable' feature in MakeProfiles (to build a 2D image a
       custom profile).

*** astscript-radial-profile
   --precision: sample the radial profile at precision less than one
     pixel. This is useful when you need to sample the profile within the
     central few pixels more accurately than integer pixels. See the
     documentation of this option in the book for a complete explanation
     with examples.

*** Library
   - GAL_ARITHMETIC_OP_SWAP: swap the top two operands.
   - GAL_ARITHMETIC_OP_INDEX: An index (counting from 0) for every element.
   - GAL_ARITHMETIC_OP_INDEXONLY: Similar to 'GAL_ARITHMETIC_OP_INDEX'.
   - GAL_ARITHMETIC_OP_COUNTER: A counter (counting from 1) for every element.
   - GAL_ARITHMETIC_OP_COUNTERONLY: Similar to 'GAL_ARITHMETIC_OP_COUNTER'.
   - GAL_ARITHMETIC_OP_COUNTS_TO_NANOMAGGY: convert counts to nanomaggy.
   - GAL_ARITHMETIC_OP_NANOMAGGY_TO_COUNTS: convert nanomaggy to counts.
   - GAL_ARITHMETIC_OP_BOX_VERTICES_ON_SPHERE: calculate the coordinates of
     vertices of a rectangle on a sphere from its center and width/height.
   - gal_binary_number_neighbors: num. non-zero neighbors of non-zero pixels.
   - gal_blank_flag_not: binary dataset with 1 for those input pixels that
     were blank.
   - gal_data_alloc_empty: Allocate an empty dataset with a given number of
     dimensions.
   - gal_list_f64_to_data: convert list of float64s to a 'gal_data_t'
     dataset with the requested type.
   - gal_list_data_remove: Remove the given dataset from the given list.
   - gal_list_data_select_by_id: find/select a dataset from a list of
     datasets using an identification string (either counter or name).
   - gal_permutation_apply_onlydim0: When we have a 2D input, apply
     permutation for all the elements of each row (along dimension-0 in C).
   - gal_statistics_has_negative: see if input has a negative value.
   - gal_table_col_vector_extract: extract the given elements of a vector
     column into separate columns.
   - gal_table_cols_to_vector: merge multiple columns into a vector column.
   - gal_units_counts_to_nanomaggy: Convert counts to nanomaggy.
   - gal_units_nanomaggy_to_counts: Convert nanomaggy to counts.
   - gal_wcs_box_vertices_from_center: calculate the coordinates of
     vertices of a rectangle on a sphere from its center and width/height.

** Removed features
*** MakeCatalog
  - Removed the short option format for the following measurements
    (columns). This was done because the short options affect the sorting
    in the output of '--help', making it hard to find the options
    visually. Because most measurements do not have a short format, we have
    seen that the short format is rarely used. Only the most commonly used
    measurements keep their short format, and only when they don't affect
    the alphabetic sorting of the output of '--help':
       --area                     (short option was 'a')
       --axis-ratio               (short option was 'Q')
       --magnitude-error          (short option was 'G')
       --num-clumps               (short option was 'c')
       --position-angle           (short option was 'p')
       --semi-major               (short option was 'A')
       --semi-minor               (short option was 'B')
       --sn                       (short option was 'n')
       --sum                      (short option was 'b')
       --upperlimit-mag           (short option was 'u')


** Changed features
*** Configuration
  --with-python: this has replaced the old '--without-python' option. The
    Python extension features in the Gnuastro library are no longer built
    by default. To have them, you need to explicitly configure Gnuastro
    with this option. This was necessary because Python has many
    peculiarities that were causing problems for users that don't need it
    in Gnuastro. These features are only necessary for those who compile
    pyGnuastro from source, most future users of pyGnuastro will be
    installing pre-built binaries it through services like PyPI, so they
    won't be needing it either.

*** CosmicCalculator
  - Given the major increase of the spectral line database, the old line
    names have been changed to accommodate the full database. For example
    'H-alpha' has replaced 'halpha'. Please run 'astcosmiccal --listlines'
    to see the new names for the previous lines.

*** MakeCatalog
  - "Sum" used instead of "brightness"
    --sum: new name for the old '--brightness' column. "Brightness" has a
      specific meaning in astronomy/physics and has units of
      energy/time. However, astronomical images aren't in this unit, they
      are usually in counts, or can have an arbitrary units (like
      nanomaggy). The new name is derived from what this column does (sum
      of pixel values) to avoid confusions.
    --sum-error: new name for '--brightnesserr'.
    --clumps-sum: new name for '--clumpbrightness'.
    --sum-no-river: new name for '--brightnessnoriver'.
  --checkuplim: now returns the center of each label's tile, not the first
    pixel (the bottom-left pixel position of the tile). The old behavior to
    return the first pixel was un-intuitive, would require several manual
    steps (to measure the minimum and maximum positions of each tile,
    measure the width along each dimension and add it), and could lead to
    confusing results when ignored. See the updated documentation of this
    option for more on custom usage in special situations.
  - Using a hyphen to help in readability and usability:
       Old name                         New name
       ========                         ========
       --areaarcsec2                    --area-arcsec2
       --areamaxv                       --area-max-val
       --areaminv                       --area-min-val
       --areaxy                         --area-xy
       --axisratio                      --axis-ratio
       --clumpsarea                     --clumps-area
       --clumpsgeow1                    --clumps-geo-w1
       --clumpsgeow2                    --clumps-geo-w2
       --clumpsgeow3                    --clumps-geo-w3
       --clumpsgeox                     --clumps-geo-x
       --clumpsgeoy                     --clumps-geo-y
       --clumpsgeoz                     --clumps-geo-z
       --clumpsmagnitude                --clumps-magnitude
       --clumpsw1                       --clumps-w1
       --clumpsw2                       --clumps-w2
       --clumpsw3                       --clumps-w3
       --clumpsx                        --clumps-x
       --clumpsy                        --clumps-y
       --clumpsz                        --clumps-z
       --fracmax                        --frac-max
       --fracmaxarea1                   --frac-max1-area
       --fracmaxarea2                   --frac-max2-area
       --fracmaxradius1                 --frac-max1-radius
       --fracmaxradius2                 --frac-max2-radius
       --fracmaxsum1                    --frac-max1-sum
       --fracmaxsum2                    --frac-max2-sum
       --geoarea                        --geo-area
       --geoareaxy                      --geo-area-xy
       --geoaxisratio                   --geo-axis-ratio
       --geopositionangle               --geo-position-angle
       --geosemimajor                   --geo-semi-major
       --geosemiminor                   --geo-semi-minor
       --geow1                          --geo-w1
       --geow2                          --geo-w2
       --geow3                          --geo-w3
       --geox                           --geo-x
       --geoy                           --geo-y
       --geoz                           --geo-z
       --halfmaxarea                    --half-max-area
       --halfmaxradius                  --half-max-radius
       --halfmaxsb                      --half-max-sb
       --halfmaxsum                     --half-max-sum
       --halfsumarea                    --half-sum-area
       --halfsumradius                  --half-sum-radius
       --halfsumsb                      --half-sum-sb
       --hostobjid                      --host-obj-id
       --idinhostobj                    --id-in-host-obj
       --magnitudeerr                   --magnitude-error
       --maxvx                          --max-val-x
       --maxvy                          --max-val-y
       --maxvz                          --max-val-z
       --maxx                           --max-x
       --maxy                           --max-y
       --maxz                           --max-z
       --minvx                          --min-val-x
       --minvy                          --min-val-y
       --minvz                          --min-val-z
       --minx                           --min-x
       --miny                           --min-y
       --minz                           --min-z
       --numclumps                      --num-clumps
       --objid                          --obj-id
       --positionangle                  --position-angle
       --riverave                       --river-mean
       --rivernum                       --river-number
       --sberror                        --sb-error
       --semimajor                      --semi-major
       --semiminor                      --semi-minor
       --sigclip-mean-sb-err            --sigclip-mean-sb-delta
       --skystd                         --sky-std
       --surfacebrightness              --sb
       --upperlimitmag                  --upperlimit-mag
       --upperlimitonesigma             --upperlimit-onesigma
       --upperlimitquantile             --upperlimit-quantile
       --upperlimitsb                   --upperlimit-sb
       --upperlimitsigma                --upperlimit-sigma
       --upperlimitskew                 --upperlimit-skew
       --weightarea                     --weight-area

*** MakeNoise
  --bgnotmag: new name for the old '--bgisbrightness' option. See the
    description of changed '--sum' in MakeCatalog (above) for more.

*** MakeProfiles
  --mcolissum: new name for the old '--mcolisbrightness' option. See the
    description of changed '--sum' in MakeCatalog (above) for more.
  - Units of the output FITS image (value to 'BUNIT' keyword) is now
    "counts", until now, it was "brightness". See the description of
    changed '--sum' in MakeCatalog (above) for more.

*** Table
  - Given the newly added vector columns, the precedence on operations has
    been updated. Please read the "Operation precedence in Table" section
    of the book.
  - To avoid potential loss of information in floating point columns, when
    printing the columns to standard output (in the terminal) or saving in
    a plain-text file, the default floating point formats are now printed
    in exponential (scientific) notation (e.g., 1.234e-5). Until now the
    default notation was fixed-point notation (e.g., 0.00001234). A new
    sub-section called "Printing floating point numbers" has been added to
    the book (under the "Table" section) to clarify this important point.
  -A: new short format for --txtf64format. The '-d' short format was
   conflicting with the short option name for '--descending'.

*** astscript-psf-select-stars
  - Now uses the Gaia DR3 dataset by default (until now it was using eDR3).

*** astscript-psf-stamp
*** astscript-psf-unite
*** astscript-radial-profile
  --axis-ratio: new name for old '--axisratio'
  --position-angle: new name for old '--positionangle'

*** Library:
  - gal_blank_remove_rows: new 'onlydim0' argument to ignore vector columns
    when checking for blanks.
  - gal_list_str_cat: new 'delimiter' argument to specify the character for
    printing between the separate string nodes in the single output string.
  - gal_txt_write: new 'tab0_img1' argument. Until now, this function would
    distinguish between images and tables using the dimensions of the
    input. But with the addition of vector columns in tables (that have 2
    dimensions) this argument becomes necessary.

** Bugs fixed
  bug #63266: Table ignores a value of 0 given to '--txtf32precision' or
              '--txtf32precision=0' (happens when floating point columns
              need to be rounded to integers). Reported by Sepideh
              Eskandarlou.
  bug #63270: Table aborts when called with '--descending' with complaint
              on '--txtf64format' (that was added in Gnuastro
              0.19). Reported by Giulia Golini.
  bug #63285: Table not printing anything in rows of integer columns with
              value of zero.
  bug #63340: Statistics printing zero for values smaller than 1e-6 and
              1e-14 for 32-bit or 64-bit floats respectively. Reported by
              Elham Saremi.
  bug #63345: WCS coordinate change not accounting for new equinox (only
              relevant for equatorial outputs). Reported by Alejandro
              Serrano Borlaug.
  bug #63399: Table's '--noblank' or '--noblankend' crashing when input
              has no rows. Reported by Elham Saremi.
  bug #63485: Oversampling in radial profile has incorrect center. Reported
              by Nafiseh Sedighi.
  bug #63543: Programs delete input when it has same name as output.
              Reported by Faezeh Bidjarchian.
  bug #63969: make distcheck error due to temporary files of
              astscript-psf-select-stars. Reported by Siyang He.
  bug #64076: MakeCatalog prints --upnum warning even with
              --quiet. Reported by Teet Kuutma.





* Noteworthy changes in release 0.19 (library 17.0.0) (2022-10-24)
** New features
*** Book
  - Two new sections added to the "General program usage tutorial" for
    describing how to prepare a FITS image for high quality publication (in
    PDF), and drawing vector graphics marks from a catalog over it (for
    example to show your selected galaxies in the field of view). The use
    the newly added features of ConvertType.

*** Arithmetic
  - Added new type operators and physical constants. All are also available
    in Table's column arithmetic also).
    - e: Base of the natural logarithm (no units).
    - pi: Fraction of Circle cirumference to diameter (no units).
    - c: speed of light in vaccume (in units of m/s).
    - G: Gravitational constant (in units of m^3/kg/s^2).
    - h: Plank's constant (in units of J/Hz).
    - au: Astronomical Units (in units of meters).
    - ly: Light years (in units of meters).
    - avogadro: Avogadro's constant (in units of 1/mol).
    - fine-structure: Fine structure constant (no units).
    - counts-to-sb: convert counts to surface brightness (mag/arcsec^2).
    - sb-to-counts: convert surface brightness (mag/arcsec^2) to counts.
    - mag-to-sb: convert magnitudes to surface brightness over an area.
    - sb-to-mag: convert surface brightness to magnitudes over an area.
  - New operators that are specific to Arithmetic:
    - collapse-median: collapse input dataset by calculating the median
      along the given dimension.
    - collapse-sigclip-std: Collapse with sigma-clipped standard deviation.
    - collapse-sigclip-mean: Collapse with sigma-clipped mean.
    - collapse-sigclip-median: Collapse with sigma-clipped median.
    - collapse-sigclip-number: Collapse with number remaining after sigma-clip.

*** ConvertType
  - It is now possible to draw vector graphics marks from a catalog over
    the output PDF images. The following options have been added to
    ConvertType for doing this. See the "General program usage tutorial"
    for a fully working example.
    --marks: name of table containing mark information.
    --markshdu: HDU of table if file given to '--marks' is FITS.
    --markcoords: name or number of two columns containing coordinates.
    --mode: if the coordinates are in 'img' (image) or 'wcs' (RA/Dec).
    --markshape: name or number of column containing the shape of each mark.
    --markrotate: name or number of column containing rotation of each mark.
    --marksize: name or number of column containing the size of the mark.
    --sizeinpix: interpret the values in the size column as pixels.
    --sizeinarcsec: interpret the values in the size column as arc-seconds.
    --sizeinarcmin: interpret the values in the size column as arc-minutes.
    --marklinewidth: name or number of column containing mark's line width.
    --markcolor: name or number of column containing mark's color.
    --listcolors: List all the 140 available colors, and show the colors on
                  24-bit (true color) terminal.
    --marktext: name or number of column containing text under each mark.
    --marktextprecision: number of decimals to print as text when the text
                         column (given to '--marktext') is floating point.
    --markfont: name or number of column containing the font to use for the
                the mark text (given to '--marktext').
    --markfontsize: name or number of column containing the size of the
                    font to use for the mark text (given to '--marktext').
    --showfonts: build a demo PDF with one page per font to show the
                 various available fonts on the system.
    --listfonts: List the names of the available fonts on the terminal.
  - It is now possible to select the color of the border of images produced
    in vector graphics outputs (EPS and PDF) with '--bordercolor'.

*** Fits
  --pixelareaarcsec2: print the image pixel area in units of arcsec^2 to
    standard output. Among other things, this is useful in creating a
    surface brightness image using the new 'counts-to-sb' operator of
    Arithmetic.
  --pixelareaonwcs: Ouput an image with the same number of pixels as the
    input. But each pixel's value shows its area on the sky (in
    degrees-squared). This area is calculated after accounting for
    distortion, projection or rotation. Implemented by Pedram
    Ashofteh-Ardakani.
  --edgesampling: extra sampling along each pixel's edge used to configure
    the output of '--pixelareaonwcs', similar to Warp.

*** Statistics
  - Linear and Polynomial least squares fitting are now available and very
    easy to call on the command-line. They are wrappers over the respective
    least squares fitting functions of the GNU Scientific Library. The
    interface is pretty simple, like the example below:
       aststatistics table.fits -cX,Y,Yerr --fit=linear-weighted
    It is also possible to estimate values and errors of the fitted model
    on a new X axis. A complete example has been added to the newly added
    "Least squares fitting" section of the book (under the Statistics
    program documentation). Please see that tutorial to easily use this
    feature. The following new options have been added to the Statistics
    program for this purpose:
    --fit: the model to use. Currently the following models are supported:
           linear
           linear-weighted
           linear-no-constant
           linear-no-constant-weighted
           polynomial
           polynomial-weighted
           polynomial-robust
    --fitweight: nature of the "weight" column (default: standard dev).
    --fitmaxpower: maximum power of X in polynomial models.
    --fitrobust: weight function to use in the "robust" polynomial model.
    --fitestimate: File name, or number to estimate the fit on.
    --fitestimatehdu: HDU containing table in file given to '--fitestimate'.
    --fitestimatecol: Column containing X axis values for '--fitestimate'.

*** Table
  - It is now possible to customize the format of floating point numbers in
    the plain-text outputs: when output is printed on the standard output
    (command-line) or in plain-text files. The following new options have
    been added for this new feature:
    --txtf32format (or '-f'): Format of 32-bit floating point columns. This
      can be either 'fixed' (for fixed-point notation) or 'exp' (for
      exponential/scientific notation).
    --txtf32precision (or '-p'): number of digits following the
      decimal-point of 32-bit floating point columns.
    --txtf64format (or '-d'): Format of 64-bit floating point columns. This
      can be either 'fixed' (for fixed-point notation) or 'exp' (for
      exponential/scientific notation).
    --txtf32precision (or '-B'): number of digits following the
      decimal-point of 32-bit floating point columns.

*** Warp
  - Can correct distortions (with any standard recognized by WCSLIB) and
    simultaneously align the image to the coordinate system. When no named
    linear operation (like '--rotate', '--scale' or etc) is requested, Warp
    will go into this mode. It is highly customizable through the following
    options. See the "Invoking Warp" section of the book for more. This
    feature has been written by Pedram Ashofteh-Ardakani.
    --center: RA, DEC of the center of the central pixel of output.
    --width: Width of output in degrees or pixels (see '--widthinpix').
    --widthinpix: interpret values of '--width' as pixels.
    --cdelt: Pixel scale of output ('CDELTi' keywords in FITS).
    --ctype: Coordinates and projection algorithm. Default: RA/Dec and
      Gnomonic or 'TAN').
    --edgesampling: extra sampling of pixel polygon to account for strong
      non-linear projection or distortion effects, when necessary.
    --gridfile: warp the input to the exact WCS and pixel grid of the file
      given to this option. This is very useful when matching images from
      differetn surveys. Using this option, you can also insert distortions
      in an image (for example on a mock image, to make it match an
      observed exposure with dithering+distortion).
    --gridhdu: HDU containing image to be matched in '--gridfile'.
    --checkmaxfrac: visualize the Moiré pattern of the warp in the second
      extension of the output. This is the maximum fraction of a single
      input pixel's area in the output pixel. When the output pixel scale
      is similar to the input, the Moiré pattern can cause varying
      artificial smoothing of the noise level. See the newly added "Moiré
      pattern and its correction" section of the book for more on its
      basics and how to reduce it in your outputs.

*** astscript-fits-view
  --ds9colorbarmulti: show a separate color-bar for each image in DS9. By
    default this script will show a single color-bar for all the images to
    help save space on the monitor when there are many images.

*** astscript-psf-stamp
  - sub-pixel warping is applied to ensure that your coordinate is at the
    center of the central pixel of the output image. This results in a
    _major_ improvement when estimating the center of the PSF.
  --nocentering: disable sub-pixel warping when creating the PSF stamp. As
    described above, the sub-pixel warping is critical for the central part
    of the PSF, but for the outer parts it is statistically negligible. So
    to avoid slowing down you pipeline, you can disable sub-pixel warping
    with this option.
  --snthresh: if given, the value to this option is assumed to be a
    signal-to-noise ratio (S/N) threshold and all pixels below that S/N
    will be masked. This is useful because we are often forced to stack
    stars of differing magnitudes. While the fainter ones are good for the
    inner parts of the star, they degrade the stack's outer parts. With
    this option, the fainter stars won't harm the outer parts.

*** GNU Make extensions (in a Makefile)
    It is now possible to use custom Gnuastro functions in GNU Make, using
    its extension facilities with Dynamic libraries. GNU Make is a very
    powerful workflow manager that is also used for data analysis (not just
    for compilation). With the Gnaustro Make functions, (astronomical) data
    analysis becomes even more easier and faster. In the following, you can
    see the first set of such functions (they all begin with 'ast-'). For
    more, see the newly added chapter in the Gnuastro manual.
    - ast-version-is: will return '1' if the running Gnuastro has the given
      version (argument of this function). This can be used to ensure
      reproducibility in combination with Make's conditional features, see
      the minimal working example in the manual.
    - ast-text-contains: will return space-separated words within a larger
      list that contain a certain string. The to-contain string can be
      anywhere within the words of the larger list.
    - ast-text-not-contains: will return space-separated words within a
      larger list that DO NOT contain a certain string. The to-not-contain
      string can be anywhere within the words of the larger list.
    - ast-fits-with-keyvalue: takes a keyword name, a list of keyword
      values, a HDU and a list of FITS files. It will return only those
      FITS files that have the requested value(s) in the requested keyword
      of the requested HDU.
    - ast-fits-unique-keyvalues: takes a keyword name, a HDU and a list of
      FITS files. It will return all the unique values given to that
      keyword within the FITS files.

*** Library:
  - GAL_CONFIG_HAVE_PYTHON: non-zero if Python3+Numpy features included.
  - GAL_CONFIG_HAVE_GNUMAKE_H: non-zero if GNU Make extensions can be made.
  - gal_box_border_rotate_around_center: width of box after rotation.
  - gal_color_id_to_name: return the name of a color from its ID.
  - gal_color_in_rgb: return the fraction of red-green-blue in a color.
  - gal_color_name_to_id: return the ID of a color from its name.
  - gal_dimension_collapse_median: collapse input along dim. using median.
  - gal_dimension_collapse_sigclip_mean: collapse with sig-clipped mean.
  - gal_dimension_collapse_sigclip_std: collapse with sig-clipped STD.
  - gal_dimension_collapse_sigclip_median: collapse with sig-clipped median.
  - gal_dimension_collapse_sigclip_number: collapse with num. after sig-clip.
  - gal_eps_shape_id_to_name: return the name of a shape from its ID.
  - gal_eps_shape_name_to_id: return the ID of a shape from its name.
  - gal_fit_name_to_id: Convert string name to ID of fitting model.
  - gal_fit_name_from_id: Convert ID of fitting model to string name.
  - gal_fit_name_robust_to_id: Convert name of robust weights to ID.
  - gal_fit_name_robust_from_id: Convert ID of robust weights to name.
  - gal_fit_1d_linear: linear fit of input columns.
  - gal_fit_1d_linear_no_constant: linear fit with no constant.
  - gal_fit_1d_linear_estimate: estimate a linear fit on a new X column.
  - gal_fit_1d_polynomial: polynomial fit of input columns.
  - gal_fit_1d_polynomial_robust: robust polynomial fit of input columns.
  - gal_fit_1d_polynomial_estimate: estimate a polynomial fit on new X column.
  - gal_fits_unique_keyvalues: extract all unique values to a certain
    keyword in many files.
  - gal_fits_with_keyvalue: select FITS image with a certain key value.
  - gal_list_data_select_by_name: select a dataset from a list by its name.
  - gal_list_str_cat: Concatenate (append) list to a space-separated string.
  - gal_list_str_extract: Extract space-separated tokens to a list.
  - gal_python_type_from_numpy: Convert Numpy's type id. to Gnuastro's.
  - gal_python_type_to_numpy: Convert Gnuastro's type id. to Numpy's.
  - gal_txt_contains_string: Check a certain string within in a larger one.
  - gal_units_counts_to_sb: SB from counts, zeropoint and area.
  - gal_units_mag_to_sb: surface brightness (SB) from magnitude and area.
  - gal_units_sb_to_counts: counts from SB, zeropoint and area.
  - gal_units_sb_to_mag: magnitude from SB and area.
  - gal_warp_pixelarea: return image of same size, but with area on sky.
  - gal_warp_wcsalign_init: initialize the WCS aligning structure.
  - gal_warp_wcsalign_onpix: Per-pixel filling of output.
  - gal_warp_wcsalign_onthread: function to give to pthreads.
  - gal_warp_wcsalign: high-level function to align input by its WCS.
  - gal_warp_wcsalign_free: free the contents of the WCS aligning structure.
  - gal_wcs_free: free a WCS structure that is created or read by Gnuastro.

** Removed features
*** Statistics
  --refcol has been removed because it breaks the modularity principle
    (given that it is the job of Gnuastro's Table program to limit rows
    from a larger table based on many different criteria). The output of
    Table can be directly piped to Statistics to achieve the same (and much
    more feature-rich effect).

*** Warp
  --align: has been removed. This is because aligning an image (while
    correcting for any possible distortion) is now the default behavior of
    Warp (when no linear operations have been requested).

** Changed features
*** Book
  - The "General program usage tutorial" section is now the first section
    of the Tutorial chapter, since it introduces the tools at a more basic
    level. The "Sufi simulates a detection" (which was previously first)
    has been moved to the fourth section.

*** Warp
  - The short format of the '--centeroncorner' option has been removed. The
    '-c' is now the short format for the new '--center' option to Warp.

*** astscript-psf-scale-factor
  --widthinpix: new name for the old '--stampwidth' option. This was done
    to have the same name to a similar option in Crop and help in
    remembering.

*** astscript-psf-stamp
  --widthinpix: new name for the old '--stampwidth' option. This was done
    to have the same name to a similar option in Crop and help in
    remembering.

*** Library
  - gal_eps_write: two new arguments have been added to draw marks, and to
        set the border color.
  - gal_pdf_write: similar to 'gal_eps_write'.
  - gal_fits_hdu_open: new argument to optionally exit program if HDU
        couldn't be opened.
  - GAL_TABLE_DISPLAY_FMT_FIXED: new name for GAL_TABLE_DISPLAY_FMT_FLOAT
    since it corresponds to the fixed-point notation of printing floating
    points in plain-text (the '_FLOAT' suffix was too generic and unclear).

** Bugs fixed
  bug #62861: '--printkeynames' of Fits program gets caught in an infinite
              loop on FITS files that have empty keywords before
              'END'. Found by Pedram Ashofteh-Ardakani.
  bug #62892: Installed scripts don't account for differing LANG and
              LC_NUMERIC. Found by Teet Kuutma and fixed by Raul
              Infante-Sainz.
  bug #62937: psf-scale-factor not being quiet, when requested. Found and
              fixed by Sepideh Eskandarlou.
  bug #62943: Couldn't read the value of width with '--snthresh' is called.
              Found and fixed by Sepideh Eskandarlou.
  bug #62944: No warning when the option value isn't immediately after the
              equal sign in long format. Found by Faezeh Bijarchian.
  bug #63013: Sigma clip segmentation fault when input has an integer type
              with values close to saturation-level.
  bug #63022: psf-scale-factor not saving the result in the output file,
              found and fixed by Raul Infante-Sainz.
  bug #63189: MakeProfiles custom profiles become NaN with a single row
              being NaN, reported by Nafise Sedighi.
  bug #63207: Match crashes when one input has no rows. Found by Sepideh
              Eskandarlou.
  bug #63257: Fits program's '--skycoverage' gives unreasonable outputs
              when image crosses the RA=0 hour circle. Found by Irene
              Pintos Castro.
  bug #63261: Radial profile script ignores central pixel in azimuthal
              profiles. Found and fixed by Sepideh Eskandarlou.





* Noteworthy changes in release 0.18 (library 16.0.0) (2022-07-21)
** New features
*** Book
   - New "Measuring the dataset limits" section has been added in second
     tutorial. Using the catalogs produced during the analysis, it shows
     how to derive a dataset's magnitude limit, completeness limit
     (crudely: without simulations), and surface brightness limit. All are
     important measures in any scientific analysis! This section was
     written with the help of S. Zahra Hosseini Shahisavandi and Sepideh
     Eskandarlou.

*** Arithmetic
   - New operators (also available in Table's column arithmetic):
     - stitch: connect any number of input images along the given dimension
       (for example to stitch the images of separate amplifiers of a CCD
       into one image).
     - noblank: Remove blank elements from the input and return a 1D output
       (irrespective of how many dimensions the input had).
     - jy-to-counts: convert Janskys to counts using an AB-magnitude-based
       Zeropoint (the inverse operator 'counts-to-jy' already existed).
     - mag-to-jy: convert AB magnitudes to Janskys.
     - jy-to-mag: convert Janskys to AB magnitudes.
     - load-col-%-from-%-hdu-%: Load a certain column into the operands
       stack. The name or number of the column is the first '%'. The file
       name hosting that column is the second '%', and HDU (if the file is
       a FITS file), is identified by third '%'. This can be used to load
       columns outside the main table in Table's column arithmetic or by
       operators that need columns as input parameters (like the new
       'random-from-hist' operator).
     - random-from-hist-raw: return a set of random points based on a
       custom distribution defined by its histogram. See the description
       and complete examples in the book for more.
     - random-from-hist: Similar to 'random-from-hist-raw', but within each
       bin, the final returned value is itself the result of a uniform
       sampling (to make the final distribution less descrete). See the
       example in the book for selecting random star magnitudes based on
       Gaia's observed magnitude distribution.
   - New options to add metadata (standard FITS keywords) to your output
     for easy understanding of the data in the future, or by your
     colleagues if you share the output). Until now, to have this feature,
     you needed to call Fits on the output of Arithmetic (for setting the
     HDU name to "my-sum" for example):
         astarithmetic img-a.fits img-b.fits + --output=sum.fits
         astfits sum.fits --write=EXTNAME,"my-sum"
     But with the following commands, you can add important metadata to the
     output of Arithmetic in the same command and simplify your scripts:
       --metaname: Metadata name of the output (FITS keyword: 'EXTNAME').
       --metaunit: Unit of the output's pixels (FITS keyword: 'BUNIT').
       --metacomment: Description of the data (FITS keyword: 'COMMENT').
     Like the following for the example above:
         astarithmetic img-a.fits img-b.fits + --metaname="my-sum" \
                       --output=sum.fits

*** Crop
   --oneelemstdout: when a crop has a single pixel and this option is
     called, the single pixel's value will be printed on the standard
     output instead of creating a FITS file. This option can be useful in
     labeled images like detection maps (when you want to see what label a
     certain coordiante/pixel corresponds to). This option was suggested by
     Raul Infante-Sainz.

*** Fits
   - When no option is specified (thus printing the HDU metadata in the
     given file), the units of the HDUs are also printed as a new
     column. For tables, it will be blank ('n/a'); because tables have
     separate units on each column (use 'asttable table.fits -i').
   --copykeys: can now take any number of keyword names also. For example
     '--copykeys=KEYNAME1,KEYNAME2,KEYNAME3'. Until now, it was only
     possible to give this option a range of keyword positions (for example
     '--copykeys=10:13' to copy the 10th to 13th keywords (inclusive). But
     now, you can also select non-contiguous set of keywords to copy from
     one HDU into another HDU (possibly in another file). This was
     suggested by Juan Antonio Fernández Ontiveros and implemented with the
     help of Jash Shah.

*** MakeProfiles
   - It is now possible to insert a custom image as a new (10th)
     'custom-img' profile. This is useful when you have no-noise FITS
     images from numerical simulations for example, and you want to insert
     those at a certain location within a larger image (while optionally
     adding existing Sersic, point or other profiles in the same
     command). The magnitude of the inserted image can be set in the
     magnitude column of the input catalog. This can be disabled (to use
     the original image pixel values) using the '--mcolnocustimg' option.
  --mcolnocustprof: new option to disable scaling of custom radial profiles
    to required magnitude when building a 2D image from them.

*** Query
   - Short name for Gaia's DR3 dataset has been added for both ESA's Gaia
     database and VizieR, for example with the following commands:
         astquery gaia   --dataset=dr3     --center=1.234,5.678 --radius=0.01
         astquery vizier --dataset=gaiadr3 --center=1.234,5.678 --radius=0.01

*** astscript-radial-profile
   --zeroisnotblank: new option to account for zero-valued pixels in the
     profile measurement. By default, during the internal cropping phase,
     zero-valued pixels are set to blank (and thus not considered during
     the profile measurement). When this option is called, it is directly
     passed to the internal cropping command ('astcrop' has an option with
     the same name). This was suggested by Ignacio Ruiz Cejudo and
     implemented by Sepideh Eskandarlou.

*** Library
   - GAL_ARITHMETIC_OP_UNIQUE: to find unique elements in dataset.
   - GAL_ARITHMETIC_OP_NOBLANK: to remove blank elements from dataset.
   - GAL_ARITHMETIC_OP_STITCH: to stitch multiple datasets.
   - GAL_ARITHMETIC_OP_RANDOM_FROM_HIST: the new 'random-from-hist' operator.
   - GAL_ARITHMETIC_OP_RANDOM_FROM_HIST_RAW: the new 'random-from-hist-raw' op.
   - gal_arithmetic_load_col: Low-level function for parsing the string of
     the newly added 'load-col' operator, mentioned in the Arithmetic
     section above.
   - gal_statistics_std_from_sums: return the standard deviation using the
     sum, sum of squares and number of a distribution.

** Removed features
** Changed features
*** MakeCatalog
   --std: measures the standard deviation of the object/clump pixels of the
          values image. Until now, there was no column to calculate this,
          and the '--std' column returned the _sky_ standard deviation over
          the object/clump labels (from the standard deviation image,
          ignoring the values image). But that was confusing, especially
          since we have columns like '--mean' or '--median' which only use
          the values image (see bug #62685).
   --skystd: new name for old '--std', see description of '--std' above.
   --sfmagnsigma: default value changed to 3 (more commonly used).
   --sfmagarea: default value set to 100 arcsec^2 (more commonly used).
   --upnum: MakeCatalog won't abort when '--upnum' is too small (less than
     20). '--upnum' defines the number of random positions for upper-limit
     measurements, so when its too small, the statistical precision of the
     result will badly affected and MakeCatalog would abort with an error
     message. However, in some scenarios (for example when the positions of
     the random apertures from '--checkuplim' are needed) the actual
     upper-limit measurements aren't relevant! So from this version,
     instead of aborting MakeCatalog, it prints a warning and
     continues. This was suggested by S. Zahra Hosseini Shahisavandi and
     Ignacio Trujillo.

*** MakeProfiles
   - The string identifier for custom radial profiles is now called
     'custom-prof' (until now, it was called 'custom'). This was necessary
     because of the new custom image feature that has been added. The code
     for this custom radial profile function (8) hasn't changed.
   - After constructing a custom radial profile (the 'custom-prof'
     profile), MakeProfiles will scale it to have the desired total
     magnitude in the input catalog of all profiles. Until now, the 2D
     images created from a custom radial profile wouldn't be touched and
     the pixel values would exactly come from the custom radial profile
     (ignoring the magnitude column of the input catalog). To have the old
     behavior, use the new '--mcolnocustprof' option. This new
     functionality was proposed by Elham Saremi.

*** Table
   --catcolumnfile: the '-N' suffix (where 'N' is a counter for the files
     with concatenated, or appended, column) is only added if a column with
     a identical column name (not case sensitive) existed in the
     table. Until now, this suffix would be added to all the newly
     concatenated columns (recall that the suffix addition can be disabled
     in general with the '--catcolumnrawname' option).
   --rowrange: new name for the old '--rowlimit'. This option takes the
     range of desired rows based on their position (for example
     '--rowrange=2,5' will only print rows 2, 3, 4 and 5 of the table). But
     the old name was very confusing and would not directly convey this
     behavior.

*** astscript-radial-profile
   --azimuth: if the first azimuthal angle is larger than the second, the
     outer region between the two angles will be used. For example
     '--azimuth=80,40' will use the full azimuthal range except for the
     region with azimuthal angles between 40 and 80 degrees. This can be
     useful to ignore parts of the profile. See the example in the
     description of this option on how to visually check the pixels used
     for the profile.

** Bugs fixed
  bug #62216: MakeProfiles crash when a 3D cube is requested and input
              catalog is from a pipe. Found by Irene Pintos Castro.
  bug #62220: astscript-psf-stamp crashes when coordinate not in image.
              Found and fixed by Sepideh Eskandarlou.
  bug #62250: Convolve crashes when doing PSF matching. Found with help of
              Raul Infante-Sainz.
  bug #62252: Radial profile giving one larger radius in high axis-ratio
              profile. Found and fixed by Sepideh Eskandarlou.
  bug #62253: Arithmetic: segmentation fault when invalid input given for
              'ra-to-degree' or 'deg-to-degree' operators. Found by Pedram
              Ashofteh-Ardakani.
  bug #62305: Not reading the 'MemFree' keyword in '/proc/meminfo' to find
              the available RAM (and thus printing an annoying
              warning). Reported by Juan Miro.
  bug #62309: MakeCatalog segmentation fault when clumps image given as
              main input (objects should be given). Reported by Sepideh
              Eskandarlou.
  bug #62429: Segment prints one line status-progress line when called with
              '--quiet'. Reported by Teet Kuutma.
  bug #62548: Table doesn't recognize plain-text string column when defined
              width is larger and it is the last column. Found with the
              help of Sepideh Eskandarlou.
  bug #62563: Some checks of installed scripts get skipped on macOS. Found
              and fixed by Raul Infante-Sainz.
  bug #62564: Arithmetic not parsing numbers in scientific notation (for
              example '1e5'). Found by Elham Saremi.
  bug #62590: Failure to build on macOS when building in debugging mode
              ('./configure --enable-debug'). Found by Raul Infante-Sainz.
  bug #62597: Arithmetic not writing single-valued output into a file when
              called with '--output'. Reported by Raul Infante-Sainz.
  bug #62636: Table ignoring '--range' when '--head' is also
              called. Reported by Sepideh Eskandarlou.
  bug #62662: Table crashes when column arithmetic is applied after adding
              rows from another file (with '--catrowfile').
  bug #62674: Column arithmetic can't use columns from --catcolumnfile.
  bug #62678: Radial profile script using values image instead of STD image
              when '--instd' not used. Found and fixed by Raul Infante-Sainz.
  bug #62679: MakeProfiles kernel only normalized when zeropoint is
              zero. Found by Raul Infante-Sainz.
  bug #62680: MakeProfiles using WCS-options when --background is given and
              the background doesn't have WCS. Found with the help of Raul
              Infante-Sainz.
  bug #62683: Arithmetic's 'set-' operator not working after the 'makenew'
              operator. Found by Raul Infante-Sainz.
  bug #62685: MakeCatalog's '--std' option is wrongly interpreted as the
              standard deviation of the values image, while it is actually
              the root mean square of the Sky standard deviation
              pixels. Found by Raul Infante-Sainz.
  bug #62694: Radial profile script overestimates the surface brightness
              error. Found and fixed with the help of Raul Infante-Sainz.
  bug #62710: Plain-text integers starting with 0 are read in the octal
              base (which is common in software engineering, but not in
              data analysis). Found by Manuel Sánchez-Benavente.
  bug #62718: Table goes into an infinite loop on some old ASCII FITS
              tables. Found by Hilderic Browne.
  bug #62720: Table not reading string columns that are shorter than the
              defined width in the metadata.
  bug #62721: Radial profile script can't deal with angles around azimuth
              zero (for example '--azimuth=355,5' to get only the azimuthal
              range of 10 degrees around the major axis). Found and fixed
              by Samane Raji.
  bug #62784: Conversion of sexagesimal RA or Dec ignores sign when first
              digit is zero (for example '-00d12m34'). Found by Manuel
              Sánchez-Benavente.
  bug #62794: psf-stamp scripts produces inconsistant outputs on
              failure. Found by Sepideh Eskandarlou and Nafise Sedighi.





* Noteworthy changes in release 0.17 (library 15.0.0) (2022-03-20)

** New features

  New programs:
   - astscript-fits-view: Given any number of FITS files, this script will
     either open SAO DS9 (for 2D images or 3D cubes) or TOPCAT (for tables)
     to visualize their contents in a graphic user interface (GUI). Both
     SAO DS9 and TOPCAT are free software packages that are heavily used in
     astrophysics. When opening in DS9, files will be opened as "match"ed
     and "lock"ed frames, enabling easy visual comparison. For GUIs that
     conform to the freedesktop.org standards, a '.desktop' file is also
     provided that you can easily activate (as described in the
     manual). Once activated, simply clicking on FITS file(s) in your
     graphic environment will open DS9 or TOPCAT depending on their
     contents. This script was suggested and partly written by Sepideh
     Eskandarlou.
   - A set of installed scripts to enable easy estimation and subtraction
     of the extended PSF (in a highly modular and easily scalable
     manner). They are primarily based on the method described in
     Infante-Sainz et al. 2020
     (https://ui.adsabs.harvard.edu/abs/2020MNRAS.491.5317I) and primarily
     maintained by Raul Infante-Sainz himself and the help of Sepideh
     Eskandarlou. A full tutorial on real data from the J-PLUS survey
     (http://j-plus.es) has also been added to the tutorials chapter to
     describe in full detail how to run these scripts in a generic way (on
     any survey). These installed scripts all have a 'astscript-psf-*'
     prefix in their names:
        - astscript-psf-select-stars: Find all the stars within an image
          that are suitable for constructing an extended PSF. If the image
          has WCS, this script can automatically query Gaia to find the
          good stars.
        - astscript-psf-stamp: build a crop (stamp) of a certain width
          around a star at a certain coordinate in a larger image. This
          script will do sub-pixel re-positioning to make sure the star is
          centered and can optionally mask all other background sources).
        - astscript-psf-scale-factor: Given a PSF model, and the central
          coordinates of a star in an image, find the scale factor that has
          to be multiplied by the PSF to scale it to that star.
        - astscript-psf-unite: Unite the various components of a PSF into
          one. Because of saturation and non-linearity, to get a good
          estimate of the extended PSF, its necessary to construct various
          parts from different magnitude ranges.
        - astscript-psf-subtract: Given the model of a PSF and the central
          coordinates of a star in the image, do sub-pixel re-positioning
          of the PSF, scale it to the star and subtract it from the image.

  Book:
   - New tutorial on how to extract the extended Point Spread Function
     (PSF) from the actual science data and how to subtract
     it. Written with the help of Raul Infante-Sainz and Sepideh
     Eskandarlou.
   - New section called "Skewness cased by signal and its measurement"
     added to the third tutorial (Detecting large extended targets). It
     describes the significant advantages of using the quantile of the mean
     as a measure of skewness and why its a very important factor when
     understanding how NoiseChisel works. It was originally written by
     Sepideh Eskandarlou, with edits by Elham Saremi and Pedram
     Ashofteh-Ardakani.
   - New section called "Integer benefits and pitfalls" added under the
     Arithmetic program's documentation. It describes the running time,
     storage and RAM consumption benefits if you use integers (where
     possible), and the issues/solutions you may confront when doing so.

  All programs:
   - Coordinate-related columns in all programs now also accept sexagesimal
     values, not just degrees. Therefore, '--center=113.8729761,31.9027152'
     and '--center=07h35m29.51,31d54m9.77' are now equivalent in the Crop
     or Query programs that have this option! Other improved options
     include the '--polygon' options of Table and Crop (that also take
     region files produced by DS9), the '--coord' option of Match, the
     '--crval' option of MakeProfiles.
   - Columns of FITS tables are now read in parallel (when '--numthreads'
     isn't set to '1', and if the dependency CFITSIO library was built with
     '--enable-reentrant'). In scenarios where many columns may be
     necessary (for example the Table or Match programs), this will greatly
     improve the running time of the programs. This task was implemented
     based on feedback from Andrés Del Pino Molina.

  Arithmetic:
   - New operators:
     - add-dimension-fast: Add a new dataset along the "fastest" dimension
       of the first dataset (in a FITS image, the "fast" dimension is the
       horizontal one). For example if you have N one-dimensional datasets
       with M elements, you can use this operator to construct a
       2-dimensional FITS image that has N pixels along the horizontal and
       M pixels along the vertical.
     - repeat: Put a copy of the given dataset onto the top of the stack of
       operators for the requested number of times.

  Crop:
   --widthinpix: when in WCS-mode, the value given to '--width' will be
     interpreted in units of pixels. This will allow having crops of a
     fixed pixel size, even when the mode of the central coordinate is in
     WCS. This was suggested by Jesús Varela.

  Fits:
   - If a 'CHECKSUM' keyword exists in a HDU and any of the keyword
     modification keywords are called, Fits will automatically update the
     checksum after all the changes are done. This is important to keep the
     checksum valid after the change (recall that you can verify the FITS
     checksums with the '--verify' option to Fits). This task was suggested
     by Tamara Civera Lorenzo.

  Table:
   - Options that accept strings ('--colmetadata', '--equal' and
     '--notequal') can now accept a comma within the string: to avoid
     confusing the comma with a separator of values, you should put a '\'
     before it. For example '--equal=AB,cd\,ef' will select all rows where
     the 'AB' column has a value of 'cd,ef'. This task was suggested by
     Zohreh Ghaffari.
   --catrowfile: File to concatenate (i.e., add or append) rows into the
     main input table. With this option, you can add the rows of another
     table into the final output. This option can be called multiple times,
     allowing you to merge rows of any number of tables. This job is done
     after concatenating columns, but before any of the row-selection
     operations. This was suggested by Raúl Infante-Sainz and Manuel
     Sánchez Benavente.
   --catrowhdu: The HDU(s) of the FITS file(s) given to '--catrowfile'.
   --noblankend: remove blank rows from selected columns of the _output_
     table, for example after after adding columns by column arithmetic or
     from other tables (this is the new name for the old '--noblank'
     option, see the changed features below). Like the new '--noblank',
     this option can also be called multiple times, so '--noblankend=1
     --noblankend=2' is equivalent to '--noblankend=1,2'.
   - New operator for column arithmetic:
     - date-to-millisec: convert the formatted date string into the number
       of milli-seconds (as a 64-bit integer) since Unix-time (00:00:00 of
       1970-01-01).

  Match:
   - k-d tree based matching has been added for finding the matching rows,
     and is set to the default mode. It will do the matching in parallel,
     which will improve the speed when many rows are present. The k-d tree
     can also optionally be saved in a file for matching new tables with
     the same one (further improving running speed). For a full description
     of Match's new behavior, please see the new "Matching algorithms"
     section of the book. This feature was implemented with the help of
     Sachin Kumar Singh.
   --kdtree: new option to specify the algorithm used by Match. It can take
     four values: 'internal' (which is the default), 'build' (to build a
     k-d tree), 'FILE.fits' (name of k-d tree to import), or 'disable' (to
     do the matching with the old sort-based method). For more, please see
     the new "Matching algorithms" section of the book.
   --kdtreehdu: the HDU of the external k-d tree (if a FITS file was given
     to '--kdtree').

  Library:
   - gal_fits_key_exists_fptr: Check if a certain keyword exists in the
     already-open FITS file pointer.

** Removed features

   Nothing was removed in this release.

** Changed features

  Arithmetic:
   - 'add-dimension-slow' is the new name for the old 'add-dimension'.

  Segment:
   - '--noobjects' is the new name for the old '--onlyclumps' option. This
     is because the name Only-Clumps can lead to a wrong expectation that
     the output will _only_ contain a 'CLUMPS' HDU. However,
     with'--onlyclumps', the input image (without a Sky level) and the Sky
     standard deviation image are also present as HDUs in the output. To
     only get the 'CLUMPS' HDU, it is necessary to also use the
     '--rawoutput' option. This renaming was done to avoid such confusions
     and was raised by Sepideh Eskandarlou.

  Match:
   - By default (when '--quiet' isn't called), Match will print the names
     of the inputs and timings of important steps to the standard output
     (on the command-line).

  Table:
   - The '--noblank' option's logic is very similar to other row-selection
     (by value) options (like '--range', '--polygon' or
     '--equal'). However, until now, it was applied at the end of Table,
     just before writing the output (so it would apply to the output table,
     that may have new/different column names/orders, not the input table
     like the other similar options). This was very inconvenient and
     non-intuitive. From this version, '--noblank' option now behaves
     similarly to the other input row-selection (by value) options. So it
     can be called multiple times (to give many columns in multiple calls)
     and it can be called for a column that is not necessarily one of the
     output columns (for example you want the RA and Dec of all rows
     without a blank magnitude, so you don't need to have the magnitude
     column any more!). The old behavior of this option is now available in
     the new '--noblankend' option. This point was raised by Samane Raji.
   - 'date-to-sec' operator now only returns the number of seconds and is
     always in a 64-bit signed integer format. Until now, if the input had
     sub-second precision it would return a 64-bit floating point type;
     however, that resulted in bug #61976 (where the loss of precision due
     to the floating-point's logarithmic scale for too many significant
     digits caused incorrect conversions).

  Library:
   - gal_fits_tab_read: now takes the number of threads to read the desired
     columns in parallel (this will greatly improve reading speed when
     there are many columns and many rows).
   - gal_table_read: similar to 'gal_fits_tab_read' (only relevant for
     reading FITS tables).
   - gal_blank_initialize: also works on string data, but initializing only
     a tile over a larger block of elements is only supported for numeric
     data types.

** Bugs fixed
  bug #61329: make check crash in macOS in convolve/spectrum-1d.sh, found
              and fixed with the help of Sebastian Luna-Valero.
  bug #61378: Table crash when input is sexagesimal RA/DEC and no metadata.
  bug #61462: Crash on FITS binary table columns with repeat of 0.
  bug #61468: DS9 region file can't be read in sexagesimal coordinates,
              reported by Juan Antonio Fernández Ontiveros and Alejandro
              Lumbreras Calle.
  bug #61490: Extra columns in the metadata causes crash in plain-text
              tables, found by Zohreh Ghaffari.
  bug #61493: NoiseChisel's --checksn not showing pseudos equal to
              --snminarea (only larger ones), found by Raúl Infante-Sainz.
  bug #61584: When FITS file doesn't end with '.fits' and the output file
              already existed, Arithmetic would write the output in new
              extension while it should have been deleted.
  bug #61598: ds9-region script not using precise WCS values, found and
              fixed by Raúl Infante-Sainz.
  bug #61698: Mean operator of Arithmetic (for stacking many images) not
              returning NaN for blank regions when input is integer. This
              fix also resolves the same problem in the 'sum', 'std',
              'median' and all 'sigclip-*' operators); reported by Zohreh
              Ghaffari.
  bug #61740: WCSLIB conflicting with system's wide-character string (WCS)
              library in Gnulib checks for some systems; reported by Martin
              Guerrero Roncel.
  bug #61940: Numbers with many decimals (like '330624.3918430004', common
              in Julian dates for example) incorrectly read as float32
              (thus loosing precision); reported by Zohreh Ghaffari, fixed
              with help of Pedram Ashofteh-Ardakani.
  bug #61967: DS9 polygon region files not read when they have width and
              color; reported by Zohreh Ghaffari, fixed by Pedram
              Ashofteh-Ardakani.
  bug #61976: Table arithmetic date-to-sec produces same result for
              different times (separated by about 1 second). This bug was
              reported by Zohreh Ghaffari and Pedram Ashofteh-Ardakani.
  bug #62008: Arithmetic not deleting existing output when the 'makenew' is
              used (no FITS file exists in the reverse polish notation).
  bug #62052: WCS decomposition of CD into PC+CDELT not setting internal
              values; reported by Ignacio Ruiz Cejudo and Raul
              Infante-Sainz.
  bug #62054: Crash in Table's '--catrowfile' when string column is present;
              reported by Manuel Sánchez-Benavente.
  bug #62069: Wrong Arithmetic result in binary operators when both input
              operands are integers of same width, but different sign (for
              example 'int32' and 'uint32'); reported by Zohreh Ghaffari
              and Pedram Ashofteh-Ardakani.
  bug #62070: Segmentation fault in Table's '--tail' option, when string
              columns are requested and the requested number of rows given
              to '--tail' is more than half of the number of rows; reported
              by Manuel Sánchez-Benavente.
  bug #62096: 'astarithmetic 250 1 +' not producing correct result;
              reported by Raul Infante-Sainz.
  bug #62112: NoiseChisel crash when '--checktiles' and
              '--continueaftercheck' called together; reported by Giulia
              Golini.
  bug #62127: GNU Scientific Library's 1D Steffen interpolation method
              (that guarantees monotonicity) not used in Gnuastro's
              library, even if it is present and found at configure time;
              found and fixed by Pedram Ashofteh-Ardakani.
  bug #62204: Column arithmetic crashes when there are no rows; reported by
              Zohreh Ghaffari.





* Noteworthy changes in release 0.16 (library 14.0.0) (2021-10-10) [stable]

** New features

  Book:
   - New section added to ConvertType's documentation for annotating the
     PDF output images with coordinates on the edges of the images, or
     tangential size at certain redshift. This is done using the PGFPlots
     package of LaTeX, directly with the same fonts and graphical settings
     as your paper/slide, while being in vector graphics quality, and not
     requiring hundreds of dependencies (only LaTeX is necessary beyond
     Gnuastro).
   - New section to describe the precedence of Table operators in one call
     to Table. Since the number of operations on table columns/rows has
     greatly increased in the last few versions, knowing this precedence
     can minimize the number of calls to Table.
   - The section on reverse polish notation (used in Arithmetic, for
     images, and column arithmetic in Table) has been edited and extended
     to be more useful for a new user.
   - Due to the great expansion of the number of operators in the
     Arithmetic program and Column Arithmetic in the table program, the
     "Arithmetic operators" section of the book has now grouped similar
     operators in sub-sections to greatly help in finding a certain option.

  Arithmetic:
   - New operands (also available in Table's column arithmetic, the
     distance conversion operators were suggested by Markus Schaney):
     - box-around-ellipse: width and height of the box covering an ellipse.
     - au-to-pc: Convert Astronomical Units (AUs) to Parsecs (PCs).
     - pc-to-au: Convert Parsecs (PCs) to Astronomical Units (AUs).
     - ly-to-pc: Convert Light-years (LYs) to Parsecs (PCs).
     - pc-to-ly: Convert Parsecs (PCs) to Light-years (LYs).
     - ly-to-au: Convert Light-years (LYs) to Astronomical Units (AUs).
     - au-to-ly: Convert Astronomical Units (AUs) to Light-years (LYs).

  CosmicCalculator:
   - A warning is printed if the requested redshift is lower than 0.007
     (corresponding to ~30Mpc in Plank 2018 cosmology). Because at these
     scales the peculiar velocity of galaxies may be significant compared
     to the Hubble flow (which is the basis of the calculations here). The
     warning can be suppressed with the '--quiet' option. This was
     suggested by Ignacio Trujillo.

  MakeCatalog:
   --areaerror: spatial resolution of image specified by user, used in
     estimating the surface brightness error.
   --sberror: error in measuring the surface brightness (mag/arcsec^2).

  MakeProfiles:
   - New type of profile showing the azimuthal angle (in degrees, along the
     elliptical circumference of fixed radius) of each pixel. In
     combination with the radial distance profile, you can now create
     complex features in polar coordinates, such as tidal tails or tidal
     shocks (using the Arithmetic program to mix the radius and azimuthal
     angle through a function to create your desired features). Implemented
     after discussions with Fernando Buitrago and Matthias Kluge.

  Match:
   - When called with '--notmatched --outcols=AAA,BBB', Match will append
     non-matching rows of second table into first table's rows (for columns
     'AAA' and 'BBB' in example above, which are assumed to exist in both
     inputs, with same numeric datatype). This allows easy/clean merging of
     two catalogs that may have matching objects into one catalog without
     repetition. See description of '--outcols' in the Match manual for
     more. This feature was proposed by Juan Molina Tobar and Leslie Hunt.

  Sort-by-night (installed script)
   --stdintimeout: new option to set internal delay time for input from
     pipes (standard input). This is not for inputs to the script (which
     should always be files), but for the script's internal pipes.

  Statistics:
   --quantofmean: the quantile of the mean of the input dataset. this is a
     very good statistic to measure skewness in a distribution, see the
     description of this option in the book for more.

  Library:
   - Arithmetic macros:
     - GAL_ARITHMETIC_OP_BOX_AROUND_ELLIPSE
   - gal_wcs_write_wcsstr: wrapper of wcshdo of WCSLIB to simplify generic
     access to that low-level operation (has some extra sanity checks).
   - gal_units_au_to_pc: Convert Astronomical Units to Parsecs.
   - gal_units_pc_to_au: Convert Parsecs to Astronomical Units.
   - gal_units_ly_to_pc: Convert Light-years to Parsecs.
   - gal_units_pc_to_ly: Convert Parsecs to Light-years.
   - gal_units_ly_to_au: Convert Light-years to Astronomical Units.
   - gal_units_au_to_ly: Convert Astronomical Units to Light-years.

** Removed features

** Changed features

  All programs:
   --stdintimeout: default value changed from 0.1 seconds to 1.5 seconds to
     avoid too many crashes when command before the pipe takes longer (thus
     needing a manual change of this value).

  MakeProfiles:
   - The default output suffix (when no '--output' is given) is now
     '_profiles.fits'. Until now, when no output name was given,
     MakeProfiles just replaced the suffix with '.fits' (effectively
     assuming the input is a plain-text file). As a result, if the input
     catalog was a FITS file, it would be automatically written-over
     (causing an error: bug #60989).

  Match:
   - The two '--notmatched' and '--outcols' can be called together (to
     create a single catalog that appends the non-matching rows of second
     table with the rows of the first. Until this version, this would cause
     an error.

  Table
   - Column concatenation (adding columns from other files) is now done
     before all row selection or row re-ording operations (if
     called). Until now, adding columns from other files was done after all
     row selection or re-ordering, but this was not too practically useful.
   - Column arithmetic operators:
     - 'wcs-to-img' new name for old 'wcstoimg' operator. The new
       unit-conversion operators generally have a '-to-' between the units
       to help in readability. So to avoid confusion, this operator has
       also been changed.
    - 'img-to-wcs' new name for old 'imgtowcs' operator (see description of
      'wcs-to-img' above).

  Library
   - gal_fits_key_write_filename: now has 'quiet' argument to avoid
     printing a warning.

** Bugs fixed
  bug #60725: MakeCatalog doesn't put comment on --halfsumsb column.
  bug #60776: Radial profile script not using standard deviation image,
              fixed by Zahra Sharbaf.
  bug #60778: Brightness error not NaN when all STD pixels are blank,
              reported by Zahra Sharbaf.
  bug #60826: Arithmetic won't delete existing file with tofile operators.
  bug #60881: Query segmentation fault when NED is called without a dataset.
  bug #60901: sort-by-night crash during make check due to stdintimeout,
              reported by Zahra Sharbaf.
  bug #60903: Increasing value of stdintimeout not effective beyond 1000000,
              reported by Zahra Sharbaf.
  bug #60909: WCS coordinate conversion not working with TPV distortion,
              fixed with the help of Mark Calabretta.
  bug #60923: Standard deviation calculation giving NaN values due to
              floating point errors, found and fixed by Natáli Anzanello.
  bug #60958: Warning on long filename not written in FITS keyword printed
              even when '--quiet' is called, found by Raúl Infante-Sainz.
  bug #60989: MakeProfiles deletes input fits catalog when no output name
              specified.
  bug #60999: No content check when plain-text table doesn't have metadata.
  bug #61007: Crash due to CFITSIO 4.0.0 version format change, reported by
              Vincenzo Testa and Zohreh Ghaffari.
  bug #61108: Plain text table metadata ignored when numeric data type was
              not understood, reported by Sepideh Eskandarlou.
  bug #61128: Radial profile: --instd and --stdhdu error when space used
              before value, found and fixed by Sepideh Eskandarlou.
  bug #61192: BuildProgram custom program linking problems on Debian-based
              OSs, reported by Raúl Infante-Sainz.
  bug #61244: Sum operator in arithmetic ignoring floating point images
              with blank values, found and reported by Giulia Golini and
              Raúl Infante-Sainz.
  bug #61287: Two "switch" blocks miss "break" in MakeCatalog when setting
              output column information, found and fixed by Vladimir
              Markelov.
  bug #61293: MakeCatalog not properly initializing the '--minvy' column
              when parsing clumps, found and fixed by Vladimir Markelov.





* Noteworthy changes in release 0.15 (library 13.0.0) (2021-05-30) [stable]

** New features

  New programs:
   - astscript-ds9-region: Given a table (either as a file or from
     standard input), create an SAO DS9 region file from the requested
     positional columns (WCS or image coordinates). For example with the
     command below you can select certain rows of a given table, and show
     them over an image:
        asttable table.fits --range=MAGNITUDE,18:20 --column=RA,DEC \
            | astscript-ds9-region --column=1,2 --radius=0.5 \
                                   --command="ds9 image.fits"
     This script was written with the help of Samane Raji.
   - astscript-radial-profile: Measure the radial profile of an object on
     an image. The profile can be centered anywhere in the image and any
     circular, or elliptical distance can be defined. The output is a table
     with the profile's value in one column and any requested measure in
     the other columns (any MakeCatalog measurement is possible). This
     script was written and is maintained by Raúl Infante Sainz. Zahra
     Sharbaf and Carlos Morales Socorro also contributed.

  All programs:
   - FITS files that don't have a recognized FITS suffix (e.g., '.fits',
     '.fit', '.fits.gz', etc) will also be recognized. Generally, it is
     good practice to keep a suffix to be more human and computer friendly
     (checking three or four characters is much faster than opening the
     file and checking the contents to conform with the FITS standard), but
     when you are given such a file (by someone else), this new feature can
     be handy. Suggested by Clotilde Laigle and Leigh Smith.

   --wcslinearmatrix: new option in all programs that lets you select the
     output WCS linear matrix format. It takes one of two values: 'pc' (for
     the 'PCi_j' formalism) and 'cd' (for 'CDi_j'). Until now, the outputs
     were always stored in the 'PCi_j' formalism (which is still the
     recommended format).

  Book:
   - New "Image surface brightness limit" section added to the third
     tutorial (on "Detecting large extended targets"). It describes the
     different ways to measure a dataset's surface brightness limit and
     upper-limit surface brightness, while discussing their
     differences. This tutorial was written with the help of Ignacio
     Trujillo and Raúl Infante Sainz.

  Arithmetic:
   - New operators (all also available in Table's column
     arithmetic).
     - sin: Trigonometric sine (input in degrees).
     - cos: Trigonometric cosine (input in degrees).
     - tan: Trigonometric tangent (input in degrees).
     - asin: Inverse of trigonometric sine (output in degrees).
     - acos: Inverse of trigonometric cosine (output in degrees).
     - atab: Inverse of trigonometric tangent (output in degrees).
     - sinh: Hyperbolic sine.
     - cosh: Hyperbolic cosine.
     - tanh: Hyperbolic tangent.
     - asinh: Inverse of hyperbolic sine.
     - acosh: Inverse of hyperbolic cosine.
     - atanh: Inverse of hyperbolic tangent.
     - mknoise-sigma: Add Gaussian noise with the fixed sigma.
     - mknoise-poisson: Add Poisson noise with the given background.
     - mknoise-uniform: Add uniform noise around existing value.
     - counts-to-mag: Convert counts to magnitudes with given zero point.
     - mag-to-counts: Convert magnitudes to counts with given zero point.
     - counts-to-jy: Convert counts to Janskys through a zero point based
          on AB magnitudes.
     Trigonometric operators proposed by Zahra Sharbaf and Samane Raji.
   --envseed: new option to get random number generator settings for the
     new 'mknoise-sigma' and 'mknoise-poisson' operators from the
     environment for reproducibility (see "Generating random numbers"
     section in manual).

  ConvertType:
   --globalhdu: Use a single HDU identifier for all the input files
     files. Its operation is identical to the similarly named option in
     Arithmetic. Until now it was necessary to call '--hdu' three times if
     you had three input FITS files with input in the same HDU.

  Crop:
   --polygon: now also accepts an SAO DS9 region file as input (as well as
     coordinates). This enables you to draw your polygon over the image
     through the GUI interface of SAO DS9, save your polygon as a "region"
     file, and feed the region file into Crop directly. Until now, the only
     way to define the polygon was to give all the polygon vertice
     coordinates, one-by-one to the '--polygon' option (which was tedious
     and buggy), but is still possible. This was implemented by Natáli
     Anzanello.

  Fits:
   --hastablehdu: print 1 if at least one table HDU exists in file.
   --hasimagehdu: print 1 if at least one image HDU exists in file.
   --listallhdus: print all HDU names (or numbers when no name exists).
   --listtablehdus: print table HDU names (or numbers when no name exists).
   --listimagehdus: print image HDU names (or numbers when no name exists).
   --printkeynames: Print all keyword names in current HDU.
   --wcscoordsys: convert the WCS coordinate system of the input into any
     recognized coordinate system. It currently supports: equatorial
     (J2000, B1950), ecliptic (J2000, B1950), Galactic and
     Supergalactic. For example if 'image.fits' is in galactic coordinates,
     you can use this command to convert its WCS to equatorial (J2000):

          astfits image.fits --wcscoordsys=eq-j2000

     This option only works with WCSLIB 7.5 and above (released in March
     2021), otherwise it will abort with an informative warning. This was
     done with the help of Mark Calabretta.
   --keyvalue: Print only the values of the FITS keywords given to this
     option in separate columns. This option can take multiple keyword
     names and many FITS files. Thus generating a table of keyword values
     (with one row per file where the first column is the file name). Its
     output can thus be written as a Table file or be piped to the Table
     program for selecting a certain sub-set of your FITS files based on
     key values, or sorting them for example. This was added after a
     discussion with Alberto Madrigal.

  MakeCatalog:
   - Newly added measurement columns:
     --upperlimitsb: upper-limit surface brightness for the given label
       (object or clump). This is useful for measuring a dataset's
       realistic surface brightness level for each labeled region by random
       positioning of its footprint over undetected regions (not
       extrapolated from the single-pixel noise level like the "surface
       brightness limit").

  NoiseChisel:
   - Can now work on 3D datacubes. Since the configuration parameters are
     different from images, it is recommended to manually set the 3D
     configuration (the '...' can be the input image and options):
         astnoisechisel --config=/usr/local/etc/astnoisechisel-3d.conf ...
     Alternatively, you can set an 'astnoisechisel-3d' alias like below and
     always easily run 'astnoisechisel-3d' on cubes.
         alias astnoisechisel-3d="astnoisechisel --config=/usr/local/etc/astnoisechisel-3d.conf"

  Segment:
   - Can now work on 3D datacubes. Similar to NoiseChisel, it requires a
     separate set of default configurations, so please see the note under
     NoiseChisel above.

  Table:
   - When given a value of '_all', the '--noblank' option (that will remove
     all rows with a blank value in the given columns) will check all
     columns of the final output table. This is handy when you want a
     "clean" (no NaN values in any column) table, but the table has many
     columns. Until now, '--noblank' needed the name/number of each column
     to "clean".
   --rowlimit: new option to specify the positional interval of rows to
     show. Until now, the '--head' or '--tail' options would just allow
     seeing the first or last few rows. You can use this new option to view
     a contiguous set of rows in the middle of the table.
   --rowrandom: Make a random selection of the rows. This option is useful
     when you have a large table and just want to see a random sub-set of
     the rows. It takes an integer, selects that many rows from the input
     randomly.
   --polygon: Similar to same option in Crop (mentioned above).
   - New column arithmetic operators:
     - 'set-AAA' operator (which allows storing the popped operand into a
       named variable for easy usage in complex operations) is also usable
       in Table's column arithmetic. Until now this operator was only
       available in the Arithmetic program (for operation on images).
     - 'date-to-sec' Convert FITS date format ('YYYY-MM-DDThh:mm:ss') into
       seconds from the Unix epoch (1970-01-01,00:00:00 UTC). This can be
       very useful in combination with the new '--keyvalue' option of the
       Fits program to operate on FITS dates (for example sort your FITS
       images based on observation time).

  Query:
   - The Galactic extinction calculator of the NASA/IPAC Extragalactic
     Database (NED) is now available for any coordinate with a command like
     below. For more, see the manual (the description of the 'extinction'
     dataset of NED in the "Available datasets" section).
         astquery ned --dataset=extinction --center=49.9507,41.5116
     This feature was suggested by Ignacio Trujillo and implemented with
     the help of Joseph Mazzarella.

  Library:
   - New arithmetic operator macros (for the 'gal_arithmetic' function):
     - GAL_ARITHMETIC_OP_SIN: sine (input in deg).
     - GAL_ARITHMETIC_OP_COS: cosine (input in deg).
     - GAL_ARITHMETIC_OP_TAN: tangent (input in deg).
     - GAL_ARITHMETIC_OP_ASIN: Inverse sine (output in deg).
     - GAL_ARITHMETIC_OP_ACOS: Inverse cosine (output in deg).
     - GAL_ARITHMETIC_OP_ATAN: Inverse tangent (output in deg)
     - GAL_ARITHMETIC_OP_ATAN2: Inverse tangent (with two inputs, out deg).
     - GAL_ARITHMETIC_OP_SINH: Hyperbolic sine.
     - GAL_ARITHMETIC_OP_COSH: Hyperbolic cosine.
     - GAL_ARITHMETIC_OP_TANH: Hyperbolic tangent.
     - GAL_ARITHMETIC_OP_ASINH: Inverse hyperbolic sine.
     - GAL_ARITHMETIC_OP_ACOSH: Inverse hyperbolic cosine.
     - GAL_ARITHMETIC_OP_ATANH: Inverse hyperbolic tangent.
     - GAL_ARITHMETIC_OP_MKNOISE_SIGMA: Add fixed-sigma noise.
     - GAL_ARITHMETIC_OP_MKNOISE_POISSON: Add Poisson noise.
     - GAL_ARITHMETIC_OP_COUNTS_TO_JY: Convert counts to Janskys.
   - New arithmetic flag macros:
     - GAL_ARITHMETIC_FLAG_ENVSEED: read random number generator seed from env.
     - GAL_ARITHMETIC_FLAG_QUIET: don't print any warnings by some operators.
   - WCS coordinate system macros:
     - GAL_WCS_COORDSYS_EQB1950: 1950.0 (Besselian-year) equatorial coords.
     - GAL_WCS_COORDSYS_EQJ2000: 2000.0 (Julian-year) equatorial coords.
     - GAL_WCS_COORDSYS_ECB1950: 1950.0 (Besselian-year) ecliptic coords.
     - GAL_WCS_COORDSYS_ECJ2000: 2000.0 (Julian-year) ecliptic coords.
     - GAL_WCS_COORDSYS_GALACTIC: Galactic coordinates.
     - GAL_WCS_COORDSYS_SUPERGALACTIC: Supergalactic coordinates.
   - gal_array_file_recognized: For FITS images, check contents also.
   - gal_ds9_reg_read_polygon: Parse the polygon from an SAO DS9 region file.
   - gal_fits_file_recognized: Check the file contents when suffix isn't FITS.
   - gal_units_counts_to_mag: Convert counts to magnitudes.
   - gal_units_mag_to_counts: Convert magnitudes to counts.
   - gal_units_counts_to_jy: Convert counts to Janskys.
   - gal_wcs_coordsys_from_string: WCS coordinate system from string.
   - gal_wcs_coordsys_identify: Parse WCS struct to find  coordinate system.
   - gal_wcs_coordsys_convert: Convert the coordinate system of the WCS.

** Removed features

** Changed features

  astscript-sort-by-night:
   - Thanks to the new features in the Fits and Table programs (described
     above), the efficiency of this script has improved dramatically (from
     19 seconds to 0.42 seconds for about 650 FITS files used in the
     test!).
   - The default end to a "night" is set to 11:00a.m. Until now it was
     9:00a.m. But in some cases, calibration images may be taken after
     that. So to be safer in general it was incremented by 2 hours.

  MakeCatalog:
   - Surface brightness limit (SBL) calculations are now written as
     standard FITS keywords in the output catalog/table. Until now, they
     were simply stored as 'COMMENT' keywords with no name so it was hard
     to parse them automatically. From this version, the following keywords
     are also written into the output table(s), see the "MakeCatalog
     output" section of the book for more: 'SBLSTD', 'SBLNSIG', 'SBLMAGPX',
     'SBLAREA', 'SBLMAG'.
   - Upper-limit (UP) settings are also written into the output tables as
     keywords (like surface brightness limit numbers above): 'UPNSIGMA',
     'UPNUMBER', 'UPRNGNAM', 'UPRNGSEE', 'UPSCMLTP', 'UPSCTOL'.

  Library:
   - GAL_ARITHMETIC_FLAG_FREE new name for GAL_ARITHMETIC_FREE.
   - GAL_ARITHMETIC_FLAG_NUMOK new name for GAL_ARITHMETIC_NUMOK.
   - GAL_ARITHMETIC_FLAG_INPLACE new name for GAL_ARITHMETIC_INPLACE.
   - GAL_ARITHMETIC_FLAGS_BASIC new name for GAL_ARITHMETIC_FLAGS_ALL.
   - gal_fits_key_write_wcsstr: also takes WCS structure as argument.
   - gal_fits_key_read_from_ptr: providing a numerical datatype for the
     desired keyword's value is no longer mandatory. When not given, the
     smallest numeric datatype that can keep the value will be found and
     used.
   - gal_wcs_read: allows specifying the linear matrix of the WCS.
   - gal_wcs_read_fitsptr: allows specifying the linear matrix of the WCS.

** Bugs fixed
  bug #60082: Arithmetic library crash for integer operators like modulo
  bug #60121: Arithmetic segfault when multi-operand output given to set-
  bug #60368: CosmicCalculator fails --setdirconf when redshift isn't given,
              reported by Sepideh Eskandarlou
  bug #60483: No warning when file given to '--config' doesn't exist,
              reported by Sepideh Eskandarlou
  bug #60484: Match crashes when called with --coord and --ccol2 (together)
  bug #60603: Table crashes with an empty input and --range,
              reported by Sepideh Eskandarlou.
  bug #60619: Crop crashes with differing image and WCS dimension
  bug #60634: Crop's '--hstartwcs' and '--hendwcs' wrong with comment keys
  bug #60644: MakeCatalog's Brightness error over-estimated in images with
              noise STD less than 1. This was not an issue for S/N or
              Magnitude error on the same image (already corrected there).





* Noteworthy changes in release 0.14 (library 12.0.0) (2021-01-25) [stable]

** New features

  Book:
   - Tutorial on "Detecting large extended targets" improved with better
     NoiseChisel configuration, and more clear description.
   - New sub-section on "Memory management" in the "Common program
     behavior" chapter. It fully describes how to optimally deal with large
     datasets that may exceed your system's RAM.
   - Examples and better description added to many operators in the
     "Arithmetic operators" subsection of the Arithmetic program's section.

  New program:
   - Query ('astquery') is a new program to query to external datasets and
     retrieve the resulting datasets from the command-line. It is possible
     to get list of datasets or column names from the databases. The basic
     spatial query (finding objects in the vicinity of a certain point) can
     be managed without knowing the query language of the database: with
     basic options (like '--center' with '--radius' or '--width'), or an
     input image that has WCS. Currently Query supports VizieR (containing
     +20500 datasets, making it the largest database in astronomy), NED, as
     ESA's Gaia database and ASTRON. See the new "Query" section of the
     book (under the "Data containers" chapter) for more.

  All programs:
   - Plain text table inputs can have floating point columns that are in
     sexagesimal format of '_h_m_s' or '_d_m_s' (where '_' is a
     number). These are the classical format to respectively represent
     Right Ascension (RA) and Declination (Dec). They will be directly read
     as a single floating point number (in units of degrees) into
     memory. Therefore the same column of a plain-text table, can be
     degrees in some rows and sexagesimal in others. Besides large tables,
     with this feature, conversion to sexagesimal coordinates to degrees
     becomes very easy, for example:
         echo "7h34m35.5498 31d53m14.352s" | asttable
     Recall that the inverse can also be done with the more general column
     arithmetic:
         echo "113.64812416667 31.88732" \
              | asttable -c'arith $1 degree-to-ra $2 degree-to-dec'
   - If input is a HEALpix grid (1D table column that represents the 2D
     spherical representation of datasets), the programs will print a
     warning, suggesting to use the 'HPXcvt' utility of WCSLIB.

  Arithmetic:
   - New operators:
     - 'interpolate-maxofregion': interpolate connected blank regions with
       the maximum value that is immediately touching it. This can be used
       to fill the blank centers of saturated stars for example.
     - 'interpolate-minofregion': similar to 'interpolate-maxofregion', but
       for the minimum.
     - 'makenew': new operator to create an empty (zero-valued) new dataset
       with given dimension and size (given as operands).

  Crop:
   --primaryimghdu: Write the final cropped image into the primary (or
     0-th) extension of the output FITS file, so the output only has
     one extension.

  Fits:
   - New '--skycoverage' option will report the area of the input image in
     RA/Dec, both in units of center/width, and box minimum/maximum
     format. This is paritcularly useful in combination with the new
     'astquery' option, to easily search the contents of external databases
     within the image.

  MakeCatalog:
   --maximum: maximum value of labeled regions pixels (clump/object).
   --areaarcsec2: area of labeled region (clump/object) in arcsec^2.
   --surfacebrightness: the surface brightness of the labeled region.
   --fwhm: observed FWHM in pixels (non-parametric), along the major axis.
   --halfmaxarea: number of pixels with a value larger than half the maximum.
   --halfmaxradius: radius of region that is larger than half the maximum.
   --halfmaxsum: sum of pixels with a value larger than half the maximum.
   --halfmaxsb: surf. brightness within half of the maximum.
   --fracmax: fractions to use in '--fracmaxarea1' or '--fracmaxarea2'.
   --fracmaxsum1: sum of pixels brighter than first given fraction of max.
   --fracmaxsum2: sum of pixels brighter than second given fraction of max.
   --fracmaxarea1: number of pixels brighter than first given fraction of max.
   --fracmaxarea2: number of pixels brighter than second given fraction of max.
   --fracmaxradius1: radius derived from '--fracmaxarea1'.
   --fracmaxradius2: radius derived from '--fracmaxarea2'.
   --halfsumsb: Surface brightness within area reported by '--halfsumarea'.
   --halfsumarea: area containing half of the summed object or clump values.
   --halfsumradius: radius derived from '--halfsumarea', underestimates r_e.
   --areaminv: the number of pixels that are equal to the minimum value.
   --areamaxv: the number of pixels that are equal to the maximum value.
   - New columns to return the position of pixel with minimum or maximum
     value: '--minvx', '--maxvx', '--minvy', '--maxvy', '--minvz',
     '--maxvz'.

  MakeNoise:
   --bgisbrightness: new option to say that the value of '--background'
     (used to simulate Poisson noise) should be interpreted as brightness,
     not magnitude.

  MakeProfiles:
   - It is now possible to make any custom radial profile with the 'custom'
     profile (with code '8'). A table should be given to the new
     '--customtable' option which will define each radial interval and the
     value to use for that radial interval. See the description of
     '--customtable' for more.

  Statistics:
   - 2D histograms can now be built as a FITS image with a linear WCS that
     contains axis values and box size. This allows using the power of FITS
     viewers for plotting/inspecting distributions of two columns in a
     table relative to each other (for example color-magnitude plots). You
     can also convert these 2D histogram images to PDF or JPEG with
     Gnuastro's ConvertType to directly use in your papers/reports (see the
     newly added "2D histogram as an image" section of the book for more).

  Table:
   - New '--noblank' option will remove all rows in output table that have
     at least one blank value in the specified columns. For example if
     'table.fits' has blank values (NaN in floating point types) in the
     'magnitude' and 'sn' columns, with '--noblank=magnitude,sn', you can
     be sure that all rows with blank values in these columns have been
     removed.
   - New trigonometric operators for column-arithmetic (inputs in units of
     degrees): 'sin', 'cos' and 'tan'. Their inverse trigonometric (outputs
     in units of degrees) have also been added: 'asin', 'acos' and 'atan'.
     The 'atan2' operator (inverse tangent that preserves the quadrant, see
     its description in the book) is also now available.
   - New hyperbolic operators for column-arithmetic: 'sinh', 'cosh' and
     'tanh'. Their inverse has also been added: 'asinh', 'acosh' and
     'atanh'.

  Library:
   - GAL_ARITHMETIC_OP_MAKENEW: new 'makenew' operator.
   - gal_binary_connected_adjacency_list: finding connected components
     without a square adjacency matrix (which can consume major RAM).
   - gal_blank_flag_remove: Remove all flagged elements in a dataset.
   - gal_blank_remove_rows: remove all rows that have at least one blank.
   - gal_dimension_dist_elliptical: Elliptical dist. of a point from center.
   - gal_fits_hdu_is_healpix: Return 1 if HDU is a HEALpix grid.
   - gal_fits_hdu_datasum: calculate DATASUM of given HDU in given FITS file.
   - gal_fits_hdu_datasum_ptr: calculate DATASUM of opened FITS file pointer.
   - gal_fits_key_list_comment_add: add a COMMENT keyword to the keyword list.
   - gal_fits_key_list_comment_add_end: add a COMMENT keyword to end of list.
   - gal_pointer_allocate_ram_or_mmap: allocate in RAM or memory-mapped file.
   - gal_pointer_mmap_free: "free" (actually delete) the memory-mapped file.
   - gal_wcs_create: create WCSLIB-compatible WCS from raw values.
   - gal_wcs_coverage: Return the sky coverage of given image HDU.
   - gal_wcs_dimension_name: return the name of the requested WCS dim.

** Removed features

** Changed features

  All programs:
   - Memory management: Until now, an internal array was only allocated in
     the RAM when its size was smaller (in bytes) than the value given to
     the '--minmapsize' option. But this was annoying/buggy when the system
     has enough RAM to keep large files. From this version, all Gnuastro
     programs will first attempt to write the array in RAM, only when it
     fails (there is no more RAM left), will they use a memory-mapped file
     (which can dramatically slow down the program). Please see the newly
     added "Memory management" section of the book for a complete
     explanation of Gnuastro's new memory management strategy.
   - When an array needs to be memory-mapped (read into a file on HDD/SSD,
     not RAM, usually due to RAM limitations), it is written in a
     'gnuastro_mmap' directory of the running directory, not the hidden
     '.gnuastro_mmap' directory. Since the files in this directory are
     usually large, it is better that the user sees them by default (in
     case the program crashes and they aren't deleted).
   --interpnumngb: the default value has been increased to 15 (from 9). The
     reason for this is that we now have a more robust outlier removal
     algorithm (see description under "NoiseChisel & Statistics").

  Crop:
   - When cropping a single image in WCS mode, there is no longer any
     limitation on the WCS. Until now for all WCS mode crops, it was
     necessary for the WCS to be aligned to the celestial coordinates. But
     from this version, this is only necessary when cropping from many
     files (and stitching them together where necessary). For WCS-mode
     crops of a single image, any WCS that is recognized by WCSLIB is fine.

  Fits:
   - The '--pixelscale' option also prints the pixel area (for 2D inputs,
     or 2D slices of 3D inputs) and the voxel volume (for 3D inputs). Until
     now, it would only print the pixel scale along each dimension.
   - When printing FITS file HDU information (no options given), a new
     "Comments" column may be printed for each HDU in the end of the line.
     It will be printed if special situations are found (for example a 2D
     HEALPix grid, that is usually stored as a 1D array/column).

  NoiseChisel & Statistics:
   - New algorithm used to reject outlying tiles. In NoiseChisel this is
     done when estimating the quantile threshold, the pseudo-detection
     threshold and the final Sky value. In Statistics, its just the Sky
     value. Unlike the previous method that used the global distribution of
     tile values to identify outliers, the new algorithm uses a relative
     measure. See the book for more. Since outliers are now rejected more
     robustly, the default value of '--meanmedqdiff' has been increased to
     0.01 (was 0.005) and '--outliersigma' has been decreased to '5' (was
     10). Also 'smoothwidth' has been increased from '3' to '5' to have
     smoother tessellation values.

  Statistics:
   - The '--histogram2d' now takes a string argument: either 'image' or
     'table'. For the old behavior please use '--histogram2d=table'. See
     the new features above for the 'image' mode.

  Table:
   - Column arithmetic operators 'degree-to-ra' and 'degree-to-dec' will
     return the sexagesimal format of '_h_m_s' and '_d_m_s'
     respectively. Until this version, they would both use colons as
     delimiters ('_:_:_').

  Library:
   - gal_pointer_mmap_allocate: new name for 'gal_pointer_allocate_mmap'.
   - gal_threads_dist_in_threads: now accounts for billions of threads,
     thus includes memory management options.
   - gal_threads_spin_off: now accounts for memory management.
   - gal_units_degree_to_ra: new 'usecolon' argument to optionally format
     output string with colons as delimiters ('_:_:_'). When this option is
     zero, the string will be in the '_h_m_s' format.
   - gal_units_degree_to_dec: similar to 'gal_units_degree_to_ra', but when
     'usecolon' is zero, the string will be in the '_d_m_s' format.

** Bugs fixed
  bug #59017: Segment's object IDs are not thread-safe (i.e., reproducible).
  bug #59105: Column arithmetic operator degree-to-ra, returning to dec.
  bug #59136: Makeprofiles with --replace is not thread-safe.
  bug #59155: Match cannot find the proper row when coordinates have NaN.
  bug #59371: MakeCatalog crash with clumps on non-contiguous object labels.
  bug #59400: CosmicCalculator fails --printparams when redshift isn't given.
  bug #59459: Unclear WCS when both PC and CD exist in input, but conflict.
  bug #59625: MakeProfiles uses last --kernel, if it is called more than once.
  bug #59700: Segment's excessive RAM usage when many clumps over a detection.
  bug #59765: MakeCatalog crash when to-be-subtracted Sky is a single-element
              per tile tessellation (e.g., NoiseChisel's '--oneelempertile').





* Noteworthy changes in release 0.13 (library 11.0.0) (2020-09-06) [stable]

** New features

  All programs:
   - When reading plain-text tables, the blank value for numeric columns
     can be any string (specified in the special comment-line format
     described in the "Gnuastro text table format" of the manual). Until
     now, it had to be a number in the same type.

  Arithmetic:
   - New operators:
     - interpolate-minngb: Fill blanks with minimum of nearest neighbors.
     - interpolate-maxngb: Fill blanks with maximum of nearest neighbors.
          This can be useful to fill the blank values of saturated stars
          for example.
   - To force integers to floats, you can also put a '.' or '.0' after
     them. Until now, it was only possibly by putting an 'f' after
     them. Hence while '5' will be read as an integer, '5.', '5.0' or '5f'
     will be read as floating point. This also applies to column arithmetic
     in Table.

  ConvertType:
   - New colormap: 'sls-inverse' is the inverse of the SLS color, good for
     printing because of a white background.

  CosmicCalculator:
   --velocity: Velocity (in km/s) to use instead of input redshift.
   --usedvelocity: Print the velocity (in km/s) at input redshift.
   --listlinesatz: Print the wavelength of all pre-defined spectral lines
     at given redshift as a simple table with the line names. This is very
     convenient and can be used in conjunction with '--obsline' for example
     to print the observed wavelength of all lines when Lyman-alpha is at
     4000 Angstroms with this simple command:
        astcosmiccal --obsline=lyalpha,4000 --listlinesatz

  FITS:
   - New '--pixelscale' option will return the size of pixels in each
     dimension in the "world coordinates".
   - New '--wcsdistortion' option allows conversion between the various WCS
     distortions. For example if you have a FITS image with the TPV-based
     WCS distortion, and you would like to convert it to a SIP-based
     distortion, you can simply run 'astfits --wcsdistortion=SIP' on the
     file. The inverse conversion is also supported (from SIP to TPV).

  Statistics
   - New feature to create a 2D-histogram using two input columns (useful
     when you have lots of points that are too dense and may hide important
     features). This mode can be activated with the new '--histogram2d'
     option. The binning of the first (X axis) column is specified with the
     same 1D histogram options. The second column's binning is configured
     with the following options:
       --numbins2: Number of bins along the second column.
       --greaterequal2: Only second column points that are larger than this.
       --lessthan2; Only second column points that are less than this.
       --onebinstart2: Make sure one bin starts at the value given here.

  Table:
   - New '--catcolumns' to specify which columns to concatenate (or append)
     to the output. You can specify the file name containing the columns to
     append with the '--catcolumnfile' option and '--catcolumnhdu' (see
     changed features because until now they had different names).
   - New '--catcolumnsrawname' will leave the name of concatenated
     (appended) columns unchanged. By default the names of the appended
     columns will be appended with a '-N' (where 'N' is a counter for the
     file that is used to append columns). The default behavior is to avoid
     multiple columns having the same name.
   - New '--colmetadata' option to add/update column metadata (name, units
     or comments) just before writing the output. This is a very useful
     feature in combination with column arithmetic or column concatenation
     because it will allow you to update the new column metadata in the
     same command. See the manual for more.

  Library:
   - Spectral lines library: SiIII, OIII, CIV, NV and rest of Lyman series.
   - GAL_CONFIG_HAVE_WCSLIB_DIS_H: if the host's WCSLIB supports distortions.
   - GAL_CONFIG_HAVE_WCSLIB_MJDREF: if the host's WCSLIB reads MJDREF keyword.
   - gal_cosmology_velocity_from_z: Calculate velocity from redshift.
   - gal_cosmology_z_from_velocity: Calculate redshift from velocity.
   - gal_data_array_ptr_calloc: Allocate array of pointers to gal_data_t
   - gal_data_array_ptr_free: Free all the datasets within the array and itself.
   - gal_fits_key_list_title_add: Add a title key word to the list.
   - gal_fits_key_list_title_add_end: Add a title key word to the list's end.
   - GAL_INTERPOLATE_NEIGHBORS_METRIC_RADIAL: Radial metric for interpolation.
   - GAL_INTERPOLATE_NEIGHBORS_METRIC_MANHATTAN: Mahattan distance.
   - GAL_INTERPOLATE_NEIGHBORS_METRIC_INVALID: For error-handling/completeness.
   - GAL_INTERPOLATE_NEIGHBORS_FUNC_MIN: Use minimum for interpolation.
   - GAL_INTERPOLATE_NEIGHBORS_FUNC_MAX: Use maximum for interpolation.
   - GAL_INTERPOLATE_NEIGHBORS_FUNC_MEDIAN: Use median for interpolation.
   - GAL_INTERPOLATE_NEIGHBORS_FUNC_INVALID: for error-handling/completeness.
   - gal_kdtree_create: Create a k-d tree for optimal spatial searching.
   - gal_kdtree_nearest_neighbour: Find the nearest neighbor using a k-d tree.
   - gal_statistics_histogram2d: Generate 2D histogram from two columns.
   - GAL_WCS_FLTERROR: Limit to identify a floating point error for WCS.
   - gal_wcs_write: Write the given WCS into a FITS extension with no data.
   - gal_wcs_clean_errors: clean major WCS components from errors specified
       by the FITS keyword 'CRDER', or floating point errors.
   - gal_wcs_distortion_from_string: Return distortion string/name from ID.
   - gal_wcs_distortion_to_string: Return distortion ID from string/name.
   - gal_wcs_distortion_identify: Identify the distortion of given WCS.
   - gal_wcs_distortion_convert: Convert between various WCS distortions.

** Removed features

** Changed features

  Arithmetic:
   - The 'pow' operator can also accept integer inputs. This also applies
     to column arithmetic in Table.

  MakeProfiles:
   - The status of every created profile (along with the number of
     remaining profiles) is no longer printed when there are more than 50
     profiles. This is done because printing itself can slow down the
     program an in a general/automated script this info is redundant.

  Table:
   --catcolumnfile ('-L') is new name for '--catcolumn' ('-C').
   --catcolumnhdu is new name for '--catcolhdu' (short option name hasn't
     changed).

  Library:
   - gal_fits_key_list_add: new 'ufree' argument to optionally free units.
   - gal_fits_key_list_add_end: similar to 'gal_fits_key_list_add'.
   - gal_interpolate_neighbors: new name for gal_interpolate_close_neighbors.
   - gal_statistics_outlier_bydistance: new name for the old
     'gal_statistics_outlier_positive'. It can now use the same algorithm
     for negative outliers with a new argument.
   - gal_txt_write: Now accepts a new argument for keyword lists.
   - gal_type_string_to_number: Numbers ending in '.' or '.0' will be
     parsed as floating point. Until now, it would only parse numbers as
     floating point if they had non-zero decimals.

** Bugs fixed
  bug #58434: MakeCatalog crash when ordering is required and no usable pixels.
  bug #58455: Timezone is not portable and uses flag instead of seconds.
  bug #58696: Warp with --centeroncorner --scale making wrong size.
  bug #58774: Warp' s output on a cube is a 2D image or wrong size.
  bug #58809: NoiseChisel not removing negative outlier tiles.
  bug #58833: Segment crashes when detection map has blank pixels.
  bug #58835: Floating point errors when comparing pixel scale in Crop.
  bug #58898: Plain text string columns touching next, clear first character.
  bug #58901: Blank values for non-standard integer types in FITS tables.
  bug #58974: WCS conversion not reasonable on processed TPV data.
  bug #59019: FITS Table crash when TFORM comes before TNULL.





* Noteworthy changes in release 0.12 (library 10.0.0) (2020-05-20) [stable]

** New features

  Arithmetic:
   - New 'quantile' operator for coadding datasets.
   - New 'size' operator to report length of dataset in requested dimension.
   - When '--wcsfile' is given the value 'none', output will not have any WCS.

  CosmicCalculator:
   --listlines: list the pre-defined spectral line wavelengths and names
     (which you can use with the '--obsline' and '--lineatz' options). This
     is convenient when you forget the specific name of the spectral line
     used within Gnuastro.

  Crop:
   --polygon: can now also crop concave polygons (when atleast one inner
     angle is more than 180 degrees). Concave polygons occur a lot in deep
     astronomical imaging: in the shape of the deepest regions.
   --polygonsort: Sort the given set of vertices to the '--polygon'
     option. For a concave polyton, the sorting will be correct, but for a
     convex polygon, there is no unique solution/sorting, so it may not be
     what you expect, see the manual.

  Fits:
   --datasum: Calculate and print the given HDU's "datasum" to stdout.
   --datetosec: Can also account for 'Z' in the end of the date-time
     string. According to 'https://www.w3.org/TR/NOTE-datetime', a 'Z'
     effectively means no time zone, or UTC time (which is the default in
     FITS). It still doesn't account for time zone hours of the w3.org
     standard.

  MakeCatalog:
   --sigmaclip: define sigma-clipping parameters for the new '--sigclip-*'
     columns.
   --forcereadstd: Read the standard deviation image even if not needed by
     any columns. This is useful when you want the surface brightness
     limit, but don't need any error-related columns.
   New output columns:
     --sigclip-number: Number of sigma-clipped pixels in object/clump.
     --sigclip-median: Sigma-clipped median of pixels in object/clump.
     --sigclip-mean: Sigma-clipped mean of pixels in object/clump.
     --sigclip-std: Sigma-clipped standard deviation of pixels in object/clump.

  Table:
   --equal: Can now work on columns with string type also.
   --notequal: Can now work on columns with string type also.
   --polygon: Polygon to use in '--inpolygon' or '--outpolygon'.
   --inpolygon: Select rows that are inside the polygon of '--polygon'.
   --outpolygon: Select rows that are outside the polygon of '--polygon'.
   --catcolumn: Concatenate tables by column (keeping number of rows fixed).
   --catcolhdu: Specify the HDU/extension of the FITS files of --catcolumn.
   - New operators in column arithmetic:
     - 'ra-to-degree': Convert Right Ascension (HH:MM:SS) to degrees.
     - 'dec-to-degree': Convert Declination (DD:MM:SS) to degrees.
     - 'degree-to-ra': Convert degrees to Right Ascension (HH:MM:SS).
     - 'degree-to-dec': Convert degrees to Declination (HH:MM:SS).
     - 'distance-flat': Distance between two points, assuming flat space.

  Library:
   - GAL_SPECLINES_INVALID_MAX: Total number of spectral lines, plus 1.
   - GAL_ARITHMETIC_OP_QUANTILE: operator for 'gal_arithmetic'.
   - gal_txt_trim_space: trim white space before and after a string.
   - gal_polygon_is_convex: identify if a polygon is convex or concave.
   - gal_polygon_is_inside: if point is inside polygon (convex or concave).
   - gal_polygon_is_counterclockwise: check if polygon is counter-clockwise.
   - gal_polygon_to_counterclockwise: convert to counter-clockwise if it isn't.
   - gal_polygon_vertices_sort: un-ordered vertices to concave/convext polygons.
   - gal_units_extract_decimal: Extract numbers from strings like "A:B:C".
   - gal_units_ra_to_degree: Convert RA (HH:MM:SS) to degrees.
   - gal_units_dec_to_degree: Convert Dec (DD:MM:SS) to degrees.
   - gal_units_degree_to_ra: Convert degrees to RA (DD:MM:SS).
   - gal_units_degree_to_dec: Convert degrees to Dec (DD:MM:SS).

** Removed features

** Changed features

  All programs and libraries:
   --minmapsize: Gnuastro's programs no longer attempt to write
     memory-mapped files under '.gnuastro'. They will only attempt to write
     them under the '.gnuastro_mmap' directory. Until now, when an internal
     array needed to be memory-mapped, Gnuastro's programs (through the
     'pointer.h' library) would first try writing the mmap files in the
     '.gnuastro' directory. When it failed it would attempt writing in the
     '.gnuastro_mmap' directory. However, '.gnuastro' is also used to store
     configuration files (which are hand-written and thus valuable). Mixing
     the two types of source (configuration files) and automatically
     generated (memory-mapped) files is very problematic.
   - FITS ASCII tables: When a column has a floating point type, but its
     ASCII string can't be parsed as a number, it will be read as a
     NaN. Until now, the corresponding program/library would abort,
     printing the problematic string and its location.

  Crop:
   --polygon: by default it will no longer attempt to sort the polygon
     vertices, sorting can be requested with the new '--polygonsort' option.
   --polygonout: is the new name for '--outpolygon'. Having 'polygon' at
     the start of the option name, makes it easier to find in the help list
     and also to understand generally.

  MakeCatalog:
   - Until now, if no standard deviation image was requested, MakeCatalog
     wouldn't include any surface brightness limit metadata in its
     output. Now, those two lines are filled, but with a notice on the
     cause (that there is no standard deviation image), and suggesting
     solutions.

  NoiseChisel:
   - Until now, when NoiseChisel didn't detect any pixels, it just printed
     a message and wouldn't not make any output file. This was very
     inconvenient in general scripts. From now on, in this scenario, an
     output file will be created and the detection map will only have a
     value of zero. As a result, the Sky and Sky standard deviation
     extensions will be measured over all the tiles.

  Table:
   - In Column arithmetic, when columns must be specified by their number,
     that number should be distinguished with a '$' before it (for example
     '$1' means the first column). Until now, this character was 'c', but
     the new identifying character is very similar to AWK, allowing easier
     adoption and is also more clear. It is just important to put the total
     'arith' string within single quotes, not double quotes.
   - Operators:
     - 'distance-on-sphere': New name for old `angular-distance' operator.

  Library:
   - gal_polygon_is_inside_convex: new name for 'gal_polygon_pin'.

** Bugs fixed
  bug #57300: MakeCatalog memory crash when input dataset has units.
  bug #57301: MakeCatalog using river sum instead of mean times by clump area.
  bug #57921: Arithmetic's interpolation operator not reading metric.
  bug #57989: Warp not accounting for translation in pixel grid.
  bug #57995: Fits lib's date to second function affected by host's timezone.
  bug #58315: Some NaNs with sigma-clip operators in Arithmetic and one input.
  bug #58371: Table crashes with a commented newline in the columns.





* Noteworthy changes in release 0.11 (library 9.0.0) (2019-11-25) [stable]

** New features

  Book:
   - The "General program usage tutorial" now has a section on how to write
     scripts effectively to automate your analysis.

  Arithmetic:
   - The new 'add-dimension' operator will stack the popped operands in a
     higher-dimensional dataset. For example to build a 3D cube from
     individual 2D images/slices.
   --onedonstdout: when the output is one-dimensional, print the values on
     the standard output, not into a file.

  BuildProgram:
   - Will use common environment variables like LDFLAGS, CPPFLAGS and CC to
     help in customizing the build of your program.
   --cc: custom C compiler to use. Until now, 'gcc' was hard-coded into the
     source and there was no way to choose a custom C compiler.
   --noenv: With this option, no environment variables will be read.

  ConvertType:
   - New 'viridis' colormap (value for the '--colormap' option). This is
     the default colormap of Python's Matplotlib, and is available in many
     other plotting tools like LaTeX's PGFPlots.

  Convolve:
   - Spatial domain convolution now possible on 3D data cubes (with a 3D
     kernel).

  CosmicCalculator:
   --lineatz: return the observed wavelength of a line if it was emitted at
     the redshift given to CosmicCalculator. You can either use known line
     names, or directly give a number as any emitted line's wavelength.

  MakeCatalog:
   - Catalogs from 3D inputs now available, with the following new options,
     see book for more.
     --spectrum: label's spectrum (across the third dimension).
     --z: Flux-weighted position in 3rd dimension.
     --geoz: Geometric center in third FITS axis.
     --minz: Minimum third FITS axis position.
     --maxz: Maximum third FITS axis position.
     --clumpsz: Flux weighted center of all clumps in object in 3rd dim.
     --clumpsgeoz: Geometric center of all clumps in object in 3rd dim.
     --w3: Flux weighted center in third WCS axis.
     --geow3: Geometric center in third WCS axis.
     --clumpsw3: Flux wheighted center of all clumps in 3rd dim.
     --clumpsgeow3: Geometric center of all clumps in 3rd dim.
     --areaxy: Projected area in first two dimensions.
     --geoareaxy: Projected geoarea in first two dimensions.
   --inbetweenints: output will contain one row for all integers between 1
     and the largest label in the input (irrespective of their existance in
     the input image). This was the default/only behavior of MakeCatalog
     until now. However, there are situations where the labeled input image
     integers may not be contiguous. For example if the input's only
     labeled pixel values are 11 and 13 from this release MakeCatalog's
     output will only have two rows. If you want the old behavior (of one
     row per integer, even if its not in the image), you can use this
     option.

  MakeProfiles:
   - Can produce mock ellipsoids in a datacube (using X-Z-X Euler angles
     for 3D orientation), the following options have been added, see the
     book for more details.
     --p2col: Second Euler angle (X-Z-X order).
     --p3col: Third Euler angle (X-Z-X order).
     --q2col: Axis ratio (major/dim3 in 3D).
   - The '--kernel' option can build 3D kernels, see the description of
     this option in the book for examples and details on how to run it.

  Match:
   - Matching of catalogs now possible using 3 coordinates (on catalogs
     generated from 3D data cubes), see book for more.

  NoiseChisel:
   - arXiv:1909.11230 added in papers to cite (with the '--cite' option):
     this paper describes the major changes made to NoiseChisel in the last
     10 stable releases since the 2015 paper, most importantly how Segment
     has been separated and the new growth strategy. It is therefore
     necessary to cite it along with the initial 2015 paper when using
     NoiseChisel.

  Segment:
   - arXiv:1909.11230 added in papers to cite (with the '--cite' option):
     this paper describes why Segment has been separated from NoiseChisel
     and some important updates to it compared to the 2015 paper, it is
     therefore necessary to cite it along with that paper when using
     Segment.

  Statistics:
   --contour: compute a contour plot which can be directly fed into the
     PGFPlots package of LaTeX for plotting the contours. Support for more
     formats will be added based on the need/request.

  Table:
   --equal: Output only rows that have a value equal to the given value in
     the given column. For example '--equal=ID,2,4,5' will select only rows
     that have a value of 2, 4 and 5 in the 'ID' column.
   --notequal: Output only rows that have a different value compared to the
     values given to this option in the given column.
   - Column Arithmetic operators:
     - 'angular-distance': a new operator to easily find the angular
       distance (along a great circle) between points in various table
       columns, or the distances of all the points in the table rows with a
       fixed point. See the book for examples and better explanation.

  Library:
   - gal_binary_connected_indexs: store indexs of connected components.
   - gal_blank_remove_realloc: Remove blanks and shrink allocated space.
   - gal_box_bound_ellipsoid_extent: Extent of 3D ellipsoid.
   - gal_box_bound_ellipsoid: Bounding box for a 3D ellipsoid.
   - gal_statistics_unique: Return unique (non-blank) elements of the input.

** Removed features

** Changed features

** Bugs fixed
  bug #56736: CosmicCalculator crash when a single value given to --obsline.
  bug #56747: ConvertType's SLS colormap has black pixels which should be orange.
  bug #56754: Wrong sigma clipping output when many values are equal.
  bug #56999: Compilation error on macOS 10.9 not recognizing AT_FDCWD.
  bug #57057: BuildProgram not using environment LDFLAGS or CPPFLAGS.
  bug #57101: Crop segmentation fault when no overlap exists in image-mode.
  bug #57164: MakeCatalog crashes when a label isn't in the dataset.
  bug #57180: MakeCatalog reporting infinity S/N when --instd isn't an image.
  bug #57200: Generated pkgconfig must request wcslib, not wcs.
  bug #57293: NaN value for brightness-related columns when values have NaN.





* Noteworthy changes in release 0.10 (library 8.0.0) (2019-08-03) [stable]

** New features

  Installation:
   - With the the following options at configure time, its possible to
     build Gnuastro without the optional libraries (even if they are
     present on the host system): '--without-libjpeg', '--without-libtiff',
     '--without-libgit2'.

  All programs:
   - When an array is memory-mapped to non-volatile space (like the
     HDD/SSD), a warning/message is printed that shows the file name and
     its size. Later, when its deleted, a warning/message is also printed,
     informing you that it has been deleted. These warnings can be very
     useful when you actually have enough RAM, but forget to increase the
     '--minmapsize' value (therefore significantly slowing down the
     program). When you don't have enough RAM, but don't want to be annoyed
     with the warnings, you can use the new '--quietmmap' option to disable
     them.

  Arithmetic:
   - 'unique' operator removes all duplicate (and blank) elements from the
     dataset and returns a single-dimension output, containing only the
     unique values in the dataset.

  Crop:
   - Can also crop 3D datasets (data cubes). A 3D crop has the same syntax
     as the old 2D mode, only when the dataset is 3D, three coordinates
     (values, ranges or catalog-columns) should be given to the relevant
     option. Just note that '--polygon' crops are still not supported in
     3D.

  CosmicCalculator:
   --obsline: alternative way to set the used redshift. With this option
     instead of explicitly giving the redshift, you can give a rest-frame
     and observed wavelength and the redshift to use will be calculated
     internally. For many lines, it is possible to give the line name
     instead of its rest-frame wavelength. For example
     '--obsline=lyalpha,6000' will use the redshift where the Lyman-alpha
     line has been shifted to 6000 Angstroms.
   --usedredshift: Print the used redshift as a "Specific calculation" (in
     line with other single-valued calculations).

  Fits:
   --primaryimghdu: Copy/cut the given image HDU to the zero-th/first
     HDU of the output file that doesn't yet exist.

  Statistics:
   --sigclip-number, --sigclip-median, --sigclip-mean, --sigclip-std: Do
     sigma-clipping and only print the desired value as a single-value
     measurement. Until now sigma-clipping results included a lot of
     visually useful information, which also made automatic usage of
     results hard. These options fix this issue. Please see the example in
     the book under '--sigclip-median' for a nice use case.

  Table:
   - Column arithmetic. It is now possible to apply many operations on the
     input table columns before printing them in the output. Similar to
     Arithmetic, but on table columns. The operators and notation is just
     like the Arithmetic program. See the "Column Arithmetic" section of
     the book for a detailed discussion and several examples.
   - WCS to Image coordinate conversion with 'wcstoimg' and 'imgtowcs'. For
     example if the input catalog has at least an 'ID' column and two 'RA'
     and 'DEC' columns, the set of options below will produce 5 columns
     where the last two columns are the image coordinates for each row
     based on the WCS in 'a.fits':
           '-cID,RA,DEC -c"arith RA DEC wcstoimg" --wcsfile=a.fits'
   --head: Only output the given number of rows from the top of columns.
   --tail: Only output the given number of rows from the bottom of columns.

  Library:
   - New 'speclines.h' library functions and macros related to spectral
     lines. It has many macros with line wavelengths, and several functions
     for using them in combination with their names.
   - list.h: Functions to return the last element in linked lists. For
     example 'gal_list_sizet_last' or 'gal_list_data_last'.
   - gal_arithmetic_operator_string: Return operator string from code.
   - gal_arithmetic_set_operator: Return operator code from string.
   - gal_blank_initialize_array: Initialize an array with blank values.
   - gal_dimension_remove_extra: Remove extra (length 1) dimensions.
   - gal_list_data_to_array_ptr: Make an array of pointers from the list.
   - gal_fits_img_info_dim: Only return the size information of a dataset.
   - GAL_TYPE_INT: Corresponding to respective width based on system.
   - GAL_TYPE_UINT: Corresponding to respective width based on system.
   - GAL_BLANK_INT: Blank value for 'int' (can be 16-bit or 32-bit).
   - GAL_BLANK_UINT: Blank value for unsigned 'int' (can be 16-bit or 32-bit).

** Removed features

** Changed features

  Installation:
   - Better './configure' tests (using Gnulib's 'AC_LIB_HAVE_LINKFLAGS') to
     avoid some crashes during 'make' when the host had multiple
     conflicting versions of some dependencies (GSL in particular).

  Arithmetic:
   - The output of co-adding operators is no longer the same type as the
     input in general. The output of the 'min' and 'max' operators are
     still the same type as the input. However the 'number' and
     'sigclip-number' operators will output an unsigned 32-bit integer type
     and the rest ('sum', 'mean', 'std', 'median', 'sigclip-median',
     'sigclip-mean' and 'sigclip-std') return 32-bit floating point
     datasets

  MakeCatalog:
   - When a clumps catalog is requested, MakeCatalog will automatically
     deduce the total number of clumps (at a small cost in
     performance). Until now, it was mandatory for the clumps label dataset
     to contain the total number of clumps in the 'NUMLABS' keyword.

  Library:
   - gal_statistics_outlier_flat_cfp: Improved implementation with new API.
   - New 'quietmmap' argument added to the following functions (as the
     argument following 'minmapsize'). For more, see the description above
     of the new similarly named option to all programs: 'gal_array_read'
     'gal_array_read_to_type', 'gal_array_read_one_ch',
     'gal_array_read_one_ch_to_type', 'gal_data_alloc',
     'gal_data_initialize', 'gal_fits_img_read',
     'gal_fits_img_read_to_type', 'gal_fits_img_read_kernel',
     'gal_fits_tab_read', 'gal_jpeg_read', 'gal_label_indexs',
     'gal_list_data_add_alloc', 'gal_match_coordinates',
     'gal_pointer_allocate_mmap', 'gal_table_read', 'gal_tiff_read' and
     'gal_txt_image_read'

  Book:
   - The two larger tutorials ("General program usage tutorial", and
     "Detecting large extended targets") have been broken into subsections
     for easier readability.
   - The "Hubble visually checks and classifies his catalog" tutorial has
     been removed because it didn't come with a dataset, so it was hard for
     people to use. Also, all its operations were already present in the
     general tutorial.

** Bugs fixed
  bug #56195: astscript-sort-by-night crashing because of AWK.
  bug #56246: Single-valued measurement must abort with no value in Statistics.
  bug #56256: Segmentation fault when reading plain text array/image.
  bug #56257: ConvertType: Values not preserved when converting text to FITS.
  bug #56299: CosmicCalculator fails at z=0.
  bug #56324: Column metadata not usable when input is from pipe/stdin.
  bug #56424: Warp crashes with empty string given to options.
  bug #56480: Segfault in statistics library's histogram function.
  bug #56641: MakeProfile's center position changes based on precision.
  bug #56635: Update tutorial 3 with bug-fixed NoiseChisel.
  bug #56662: Converting -R to -Wl,-R causes a crash in configure on macOS.
  bug #56671: Bad sorting with asttable if nan is present.
  bug #56709: Segment crash when input has blanks, but labels don't.
  bug #56710: NoiseChisel sometimes not including blank values in output.





* Noteworthy changes in release 0.9 (library 7.0.0) (2019-04-17) [stable]

** New features

  All programs:
   --checkconfig: print the names and values given to options as they are
     parsed on the command-line or in various configuration files (the
     configuration file name is also printed). This can be very useful in
     debugging (finding which configuration file is responsible for a given
     option's value).

  Arithmetic:
   - The new 'tofile-' and 'tofilefree-' operators will save the top
     operand into a file. They can be very handy in debugging/understanding
     an Arithmetic command (especially as it gets complicated), or to
     produce multiple files/extensions with a single call to Arithmetic.
   - Four new operators have been added to allow coadding multiple datasets
     into one using sigma-clipping: 'sigclip-number', 'sigclip-mean',
     'sigclip-median', and 'sigclip-std'. These are very useful when
     several inputs have strong outliers that affect the median, or the
     mean is required.
   - Multithreaded operation for the following operators that
     combine/co-add multiple inputs into one output with same size: 'min',
     'max', 'number', 'sum', 'mean', 'std', 'median', 'sigclip-number',
     'sigclip-median', 'sigclip-mean', 'sigclip-std'.
   --wcsfile and --wcshdu: these two options can be used to specify a
     different file for reading the WCS of the output. This is useful when
     the default (the WCS of the first dataset that is read) is not the
     required one.
   --interpmetric: new option that is necessary with the
     'interpolate-medianngb' operator. For more, see the description of
     this option in NoiseChisel.

  Fits:
   - Add "title" to group FITS keywords with '--write=/,"title name". This
     "title" is composed of two keyword records/lines: a blank one (all
     whitespace), followed by another starting with '/' and ending in any
     string given to this option. This visually separates the keywords and
     acts as a title. Classifying the keywords into contextually similar
     groups greatly helps in visual inspection and is encouraged.
   - Calculate and write 'CHECKSUM' and 'DATASUM' integrity keywords into
     the specified header using '--write=checksum' (for both) or
     '--write=datasum' (only for 'DATASUM').
   --datetosec: Convert the FITS date format (old or new) to number of
     seconds since since the Unix epoch time (1970-01-01,00:00:00). The
     FITS date format (for example 'YYYY-MM-DDThh:mm:ss') is hard to use
     for automatic processing (requires calendar peculiarities like number
     of days in each month, or leap years and etc). With this option a
     single integer is returned that can be used for example to sort FITS
     files by date keywords without worrying about calendar peculiarities.
   --verify: confirm if the 'DATASUM' and 'CHECKSUM' keyword values agree
     with the specified HDU's content and/or data.
   --copykeys: Copy several keyword records (in a given range) from one
     FITS HDU/extension into another (possibly in another file).
   --outhdu: The name/number of the output HDU (for '--copykeys').

  Match:
   - All the columns from one of the input catalogs can now be merged with
     any of the columns of the second using the special '_all' name of
     '--outcols'. For example the output of '--outcols=a_all,b5' will
     contain all the columns from the first input and the 5th column of the
     second input. This greatly simplifies the merging of different table
     columns into one.
   --coord: manually specify coordinates to match on the
     command-line. Until now, if you only wanted to make check a specific
     coordinate's matching with a catalog. It was necessary to make a
     single-row catalog as a file and feed that into Match. With this
     option, you can now specify the coordinates to match against another
     catalog with the command-line.

  NoiseChisel:
   --interpmetric: Set the metric to use to identify the nearest neighbors
     for tile interpolation (quantile threshold, initial Sky, and final
     Sky). Until now only the manhattan/taxicab metric was available, which
     is fast, but could cause 45-degree lines in the interpolation. From
     this version, with this option, its also possible to use the radial
     distance (which is now the default). Just note that if there are many
     tiles over the image, the radial distance will be slower.
   --snthresh: Manually set the signal-to-noise ratio of true
     pseudo-detections. With this option, NoiseChisel will not attempt to
     find pseudo-detections over the noisy regions of the dataset, but will
     directly go onto applying the manually input value.
   - Several new options have been added to remove NoiseChisel's dependence
     on values that were hard-coded in its source and thus not modifiable
     at run-time by the user. To allow full configurability, these steps
     can also be configured by the user.
     --pseudoconcomp: allows setting the connectivity (4 or 8, in a 2D
       image) to define separate pseudo-detections. If its stronger,
       pseudo-detections that are touching on the corner will be identified
       as one.
     --dopening: The number of openings to do after applying '--dthresh'.
     --dopeningngb: The connectivity (4 or 8) to use for '--dopening'.

  Statistics:
   --interpmetric: Similar to NoiseChisel.

  Table:
   --range: Limit the output rows to those with a value within the given
     numeric range with this format: '--range=COL,low,high'. This is very
     useful when only certain rows of the input are required not the
     output. The advantage over piping to AWK is that you can save the
     output directly to FITS (preserving the metadata). See the book for
     more.
   --sort: Sort the output rows based on the value of the given column in
     ascending order.
   --descending: When called with '--sort', will arrange the output rows in
     descending order.

  Installed scripts:
   With this release, Gnuastro also installs Bash scripts for common
   higher-level usage of (possibly multiple) programs. These scripts have a
   'astscript-*' name, to easily show up on the command-line as Gnuastro
   executables with the other Gnuastro programs, but are identifiable from
   them. They support options just like the programs (which can be listed
   with '--help'). Please see the new "Installed scripts" chapter of the
   book for more.
   - astscript-sort-by-night: New Gnuastro executable, using Gnuastro's
     Fits program to identify files with dates in the same night (possibly
     spanning two calendar dates).

  Library:
    GAL_BLANK_LONG: new macro for the 'long' type blank value.
    GAL_BLANK_ULONG: new macro for the 'unsigned long' type blank value.
    gal_blank_number: Return the number of blank elements in a dataset.
    gal_dimension_dist_radial: Radial distance between two coordinates.
    gal_fits_key_date_to_struct_tm: FITS date format to C broken-down time.
    gal_fits_key_date_to_seconds: FITS date format to Unix epoch time.
    gal_qsort_index_single_TYPE_i: Set of functions to sort indexs ascending.
    gal_qsort_index_single_TYPE_d: Set of functions to sort indexs descending.
    gal_statistics_outlier_cumulative: Uses flatness of the cumulative
       distribution to find outliers.
    gal_table_list_of_indexs: returns the list of indexs matching columns.
    gal_type_is_int: to see if we have an integer (any width, any sign).

** Removed features

** Changed features

  Arithmetic:
   - 'num' operator is renamed to 'number'.
   - 'numvalue' operator is renamed to 'numbervalue'.
   - '--dontdelete' will append the output to any existing file. Note that
     this change is only in Arithmetic, other programs will still just
     complain and abort.

  ConvertType:
   --forcemin & --forcemax: until now, '--flminbyte' and '--flmaxbyte' were
     used to force the range of conversion to color channels (even if the
     range is beyond the limits of the dataset). With the introduction of
     color maps in Gnuastro 0.8, it is also necessary to force a range on
     non-byte datasets. It is thus necessary to use a more generic name.

  MakeCatalog:
   --std: Until now, this option would measure the mean standard deviation
     under the label. But this is not a statistically meaningful measure
     for the Sky standard deviation and could be incorrectly used. From now
     on, this option measures the square root of the mean variance, or root
     mean square (the correct definition of the Sky standard deviation).

  NoiseChisel:
   --ignoreblankintiles: Until now '--ignoreblankinsky', would specify if
     blank values should also be written into the tiled Sky and Sky
     standard deviation outputs. But NoiseChisel can optionally produce
     many more tiled outputs (for example with '--checkqthresh'). So the
     option was renamed to '--ignoreblankintiles' to highlight that the
     status of blank elements can be set in all tiled outputs.

  Statistics:
   --ignoreblankintiles: similar to same option in NoiseChisel.

  Table:
   --colinfoinstdout: now corresponds to the '-O' short option. Until this
     version, the '-s' short option was used for it. But with the new
     '--sort' option, '-s' may cause confusion.

  Library
   gal_arithmetic: new argument: number of threads to use (when relevant).
   gal_eps_write: new argument: optional bit-optimization with 'dontoptimize'.
   gal_pdf_write: new argument: optional bit-optimization with 'dontoptimize'.

** Bugs fixed
  bug #55313: Fits program writing --write values in reverse order
  bug #55333: Fits program crash when --write or --update have no value.
  bug #55439: Arithmetic segmentation fault when reusing dataset name.
  bug #55478: Memory mapping crashes when .gnuastro is not writable.
  bug #55491: NoiseChisel crash when no tiles good for quantile thresholding.
  bug #55544: Arithmetic's output WCS with where operator is not as expected.
  bug #55740: Diamond shapes in nearst-ngb interpolation affecting NoiseChisel.
  bug #55763: Crop not keeping Blank pixels on unsigned types.
  bug #55844: WCS library (and thus all programs) can't deal with CROTAi values.
  bug #55845: Crash when necessary column not found from standard input.
  bug #55988: MakeProfiles segfault when input catalog has no rows.
  bug #56001: Bad tile sizes with only one tile and small remainder.
  bug #56048: Crash when WCS cannot be written to FITS file.





* Noteworthy changes in release 0.8 (library 6.0.0) (2018-12-28) [stable]

** New features

  All programs:
   - Input files and parameters written as keywords in the first extension
     of output when it is FITS. This is only relevant for some programs,
     (for example not the Fits or Table programs).
   - Standard input (for example from pipes) is now available to feed input
     to all programs that accept plain text input (ConvertType, Convolve,
     Match, MakeProfiles, Statistics, Table).
   - Updated acknowledgment statement (output of '--cite' option).

  Arithmetic:
    --onedasimage: write output as an image if it has one dimension, not table.

  ConvertType:
    --colormap: color map to display a single-channel dataset (for example
      FITS image) with a range of colors in formats that support color
      (like JPEG, or PDF). Until now, the only available mapping was
      grayscale. Now "Hue, Saturation, Value" (HSV) and "SLS" (from SAO
      DS9) colormaps are also supported.
    --rgbtohsv: Convert the RGB input channels to HSV (when the output is
      in FITS format).

  Convolve:
    - Convolves 1D arrays (table columns, for example spectra)
      also. Therefore two new options have been added to it: '--column'
      ('-c', similar to other programs that read table columns), and
      '--kernelcolumn' (to specify the column of the kernel in its own
      file/extension).

  Fits:
    --numhdus: prints the number of HDUs in the given FITS file.

  NoiseChisel:
    - New outlier identification algorithm for quantile thresholds. This is
      very useful when there are extended and bright sources in the
      dataset: the tiles containing very faint signal that pass the general
      pixel-value distribution test due to the flatness of the extended
      profiles, can be identified and removed as outliers in comparison
      with the other passed tiles. The outlier finding algorithm
      ('gal_statistics_outlier_positive': a new library function) uses the
      distribution of distances between the sorted elements and is
      configured with these options.
       --outliersclip: Sigma-clipping parameters for the process.
       --outliersigma: Multiple of sigma to define an outlier.
    --blankasforeground: Treat blank elements as foreground (regions above
          the threshold) in the binary processing steps: initial erosion
          and opening as well as the filling holes and opening of
          pseudo-detections. From this version, by default, blank elements
          in the dataset are considered to be background, so if a
          foreground pixel is touching it, it will be eroded. This option
          is irrelevant if the datasets contains no blank elements, but can
          help remove false positives that are touching blank elements.
    --holengb: allows defining the connectivity of the holes that are
          filled when defining pseudo-detections. Until now, this was
          hard-wired into the code (=8) and not modifiable at run-time.
    --skyfracnoblank: Ignore blank pixels when estimating the fraction of
          undetected pixels for Sky estimation. NoiseChisel only measures
          the Sky over the tiles that have a sufficiently large fraction of
          undetected pixels. This is done to decrease the bias caused by
          faint un-detected wings of bright galaxies or stars, see
          description of '--minskyfrac' for more. Until now the reference
          for this fraction was the whole tile size (irrespective of how
          many blank elements it contains). With this option, it is now
          possible to ask for ignoring blank pixels when calculating the
          fraction. This is useful when blank/masked pixels are distributed
          across the image.

  Statistics:
    - If an input table has only one column, Statistics won't complain and
      abort when no '--column' ('-c') is given: there is only one column to
      use anyway, so it will be used. In the absence of which column to
      use, it will still complain and abort if the input has more than one
      column.
    - Sky estimation: new outlier estimation algorithm similar to
      NoiseChisel.
    - Input can be given using the standard input (for example a pipe).

  Library:
    - gal_blank_flag_apply: Set all flagged/masked elements to blank.
    - gal_fits_key_list_reverse: Reverse the given list of FITS keywords.
    - gal_fits_key_write_title_in_ptr: Write a two-line title FITS keyword.
    - gal_fits_key_write_in_ptr: New name of gal_fits_key_write.
    - gal_fits_key_write_version_in_ptr: old gal_fits_key_write_version.
    - gal_fits_key_write_config: write key list and version as config header.
    - gal_statistics_outlier_positive: Find the first positive outlier.
    - gal_txt_stdin_read: Read lines in standard input into a list of strings.

** Removed features

  NoiseChisel:
    --mirrordist: mean quantile is now used (not mode), see changes below.
    --qthreshtilequant: removed due to new outlier rejection algorithm.

  Statistics:
    --mirrordist: mean quantile is now used (not mode), see changes below.

** Changed features

  Arithmetic:
    - If the output has one dimension, it will be written as a table, not a
      FITS image/array. This can be changed with the new '--onedasimage'
      option.

  Convolve:
    - The short option for '--numchannels' is now '-n'. Until now, it was
      '-c', but that would conflict with the short option used for
      '--column' in all the other programs that also read from a table.

  MakeProfiles:
    --mergedsize: new name for the old '--naxis' option. Since the option
          names and values are now written into the FITS header of the
          output, this option's name would get confused with the mandatory
          FITS keyword 'NAXIS'.

  NoiseChisel:
    - Until now, the mode's quantile was used to identify tiles with no
      significant signal. But from this version, the mean's quantile in
      each tile is used instead. The reason is that the mean is more
      sensitive to outliers (signal). Therefore the old '--modmedqdiff' is
      now called '--meanmedqdiff' .

  Statistics:
    --meanmedqdiff: new name for '--modmedqdiff'. Similar to NoiseChisel.

  Library:
    - gal_array_read: list of strings (from standard input) acceptable.
    - gal_array_read_to_type: list of strings (from stin) acceptable.
    - gal_array_read_one_ch: list of strings (from stdin) acceptable.
    - gal_array_read_one_ch_to_type: list of strings (from stdin) acceptable.
    - gal_data_copy_to_allocated: Also copies string metadata (e.g., name).
    - gal_fits_key_write: filename and hdu instead of FITS pointer.
    - gal_fits_key_write_version: filename and hdu instead of FITS pointer.
    - gal_fits_key_write_filename: write at the top or end of the input list.
    - gal_statistics_outlier_positive: Window-size is now adjustable (new argument).
    - gal_table_info: list of strings (from stdin) acceptable.
    - gal_table_read: list of strings (from stdin) acceptable.
    - gal_txt_table_info: list of strings (from stdin) acceptable.
    - gal_txt_image_info: list of strings (from stdin) acceptable.
    - gal_txt_table_read: list of strings (from stdin) acceptable.
    - gal_txt_image_read: list of strings (from stdin) acceptable.

** Bugs fixed
  bug #54493: Warp crashes when type isn't set.
  bug #54526: Invalid r, q and truncation of point profiles in MakeProfiles.
  bug #54579: NoiseChisel pseudo-detection failure when dataset is negative.
  bug #54782: Segment's check image not removing sky clumps some tiles.
  bug #54810: Arithmetic crash when previously named operand renamed.
  bug #55025: MakeCatalog's '--prepforconv' option being ignored.
  bug #55079: Blank EPS or PDF page when width options not given.
  bug #55157: No sanity check on values given to Crop's --section.
  bug #55295: Crash when more than one collapse operator called.
  bug #55298: Arithmetic reading 255 on command-line as blank.





* Noteworthy changes in release 0.7 (library 5.0.0) (2018-08-08) [stable]

** New features

  Installation:
    --enable-debug: debugging flags, no optimization, no shared libraries.
    --enable-check-with-valgrind: Run 'make check' tests within Valgrind.

  Arithmetic:
    - 'set-A': Set a name ('A' in this case) for the popped dataset. This
               allows only reading the dataset it into memory once and
               possibly using it many times.
    - 'fill-holes': Flip background (0) pixels surrounded by foreground (1).
    - 'collapse-sum': collapse/remove a dimension by summing over it.
    - 'collapse-min': collapse/remove a dimension by using minimum value.
    - 'collapse-max': collapse/remove a dimension by using maximum value.
    - 'collapse-mean': collapse/remove a dimension by averaging over it.
    - 'collapse-number': Number of elements included in the collapse.

  CosmicCalculator:
    - Default cosmology set to Plank 2018 results (Paper VI).

  MakeCatalog:
    --minx: minimum position along first FITS axis.
    --maxx: maximum position along first FITS axis.
    --miny: minimum position along second FITS axis.
    --maxy: maximum position along second FITS axis.

  Table:
    --colinfoinstdout: column information when writing to standard output.

  Library:
    - gal_array_name_recognized_multiext: If format contains multiple datasets.
    - gal_dimension_collapse_sum: collapse/remove a dimension by summing.
    - gal_dimension_collapse_mean: collapse/remove a dimension by averaging.
    - gal_dimension_collapse_number: collapse/remove a dimension by number.
    - gal_dimension_collapse_minmax: collapse/remove a dimension by extremum.
    - gal_wcs_remove_dimension: Remove a dimension in the given WCS structure.

** Removed features

** Changed features

  Crop:
    --checkcenter: the units of value depend on mode (image or WCS).

  MakeCatalog:
    - '--checkuplim': new name for '--checkupperlimit'.
    - '--brightnessnoriver': new name for '--noriverbrightness'.

  Library:
    - gal_txt_write: new 'colinfoinstdout' argument.
    - gal_table_write: new 'colinfoinstdout' argument.

** Bugs fixed

  bug #54057: Building failure due to not finding gsl_interp_steffen.
  bug #54063: Match tests in make check fail randomly.
  bug #54186: MakeCatalog's --checkupperlimit not keeping output's name.
  bug #54188: MakeCatalog's Upperlimit not being sigma-clipped properly.
  bug #54284: Crop segfault when catalog contains no data.
  bug #54285: make check fails if g++ not present.
  bug #54286: BuildProgram's configuration file, not built by default.
  bug #54297: No Match output when --notmatched called and no match.
  bug #54298: Table not writing array when there are no rows.
  bug #54312: Crash when CFITSIO doesn't have fits_is_reentrant function.
  bug #54346: Non '-I' or non '-L' strings in CPPFLAGS or LDFLAGS cause crash.
  bug #54358: Arithmetic's where, not ignoring blank values in condition.
  bug #54406: Insufficient sanity checks in mode symmetricity calculation.
  bug #54430: BuildProgram fails with older Libtool versions on dash.




* Noteworthy changes in release 0.6 (library 4.0.0) (2018-06-04) [stable]

** New features

  Building:
    - New optional dependency: The TIFF library (libtiff).

  All programs:
    - Input image dataset(s) can be in any of the formats recognized by
      Gnuastro (e.g., FITS, TIFF, JPEG), provided that their libraries
      (optional dependencies) were present at installation time.

  New program:
    - Segment: new program in charge of segmentation over detections. This
      operation was previously done by NoiseChisel. NoiseChisel is now ONLY
      in charge of detection.

  Arithmetic:
    - erode: Erode the foreground of a binary dataset.
    - dilate: Dilate the foreground of a binary dataset.
    - filter-sigclip-mean: sigma-clipped, mean filter operator.
    - filter-sigclip-median: sigma-clipped, median filter operator.
    - connected-components: label the connected elements of the input.
    - invert: subtract the maximum of unsigned types (absorption to emission).
    - interpolate-medianngb: Interpolate (only blanks) with nearest neighbors.

  ConvertType:
    - TIFF images can also be used as input.

  MakeCatalog:
    MakeCatalog will only read the datasets necessary for the requested
    columns. Until now, it would read all the possible datasets and all the
    intermediate measurements. This is thus major improvement in memory and
    CPU usage. As a result, the input argument is no longer assumed to be
    the values file, but the object labels file. Please see the
    "MakeCatalog inputs and basic settings" section of the book for
    more. Here is the summary of the new options:
    --insky: Sky value as a single value or file (dataset).
    --instd: Sky standard deviation as a single value or file (dataset).
    --valuesfile: filename containing the values dataset.
    --valueshdu: HDU/extension containing the values dataset.
    --clumpscat: Make a clumps catalog also.
    --noclumpsort: Don't sort the clumps catalog by host object ID.
    --subtractsky: Subtract the given Sky from the values dataset.
    --variance: input standard deviation image is actually variance.
    --checkupperlimit: make a table for random positions and measurements.
    --geoarea: the number of labeled pixels (irrespective of value).
    --brightnesserr: error in estimating the brightness.
    --mean: calculate the mean pixel value within an object or clump.
    --median: calculate the median pixel value within an object or clump.
    --upperlimitsigma: position in random distribution (in units of sigma).
    --upperlimitquantile: position in random distribution (quantile).
    --upperlimitonesigma: 1sigma value of the random distribution.
    --upperlimitskew: (mean-median)/sigma or skewness of random distribution.

  NoiseChisel:
    - New tutorial on detecting large and extended targets.
    --rawoutput: only output the detection labels and Sky and its STD.
    --ignoreblankinsky: don't set the pixels that are blank in the input to
      blank in the Sky and Sky standard deviation outputs (when
      '--oneelempertile' is not called).
    --label: label the connected detections. Until now this was the default
      behavior. However, from this release, NoiseChisel is only in charge
      of detection. Segmentation is done by a new program (Segment). Since
      detection is ultimately just a binary operator, the default output
      now has an 8-bit unsigned integer type with values of 0 or 1. With
      this option, you can ask for it to label/count the connected
      detections instead of the default binary output.

  Statistics:
    --manualbinrange: histogram or CFP range can be outside of distribution.
    --ignoreblankinsky: similar to same option in NoiseChisel.

  Libraries:
    gal_array_read: read array from any of known formats (FITS, TIFF, JPEG,...).
    gal_array_read_to_type: similar to 'gal_array_read', but to given type.
    gal_array_read_one_ch: Read a dataset, abort if it has multiple channels.
    gal_array_read_one_ch_to_type: Make sure input is in one channel and type.
    gal_binary_label_holes: label the holes within the foreground.
    gal_blank_is: check to see if argument is blank in its type or not.
    gal_eps_name_is_eps: Returns 1 if given filename is EPS.
    gal_eps_suffix_is_eps: Returns 1 if given suffix is EPS.
    gal_eps_to_pt: Converts dataset size to PostScript points.
    gal_eps_write: Writes a dataset into an EPS file.
    gal_interpolate_1d_blank: Fill blank elements through interpolation.
    gal_interpolate_1d_make_gsl_spline: Allocate and initalize 'gsl_spline'.
    gal_jpeg_name_is_jpeg: Returns 1 if given filename is JPEG.
    gal_jpeg_suffix_is_jpeg: Returns 1 if given suffix is JPEG.
    gal_jpeg_read: Reads input JPEG image into 'gal_data_t'.
    gal_jpeg_write: Writes a 'gal_data_t' into a JPEG file.
    gal_label_grow_indexs: grow known indexs into desired areas.
    gal_label_watershed: apply watershed algorithm on desired region.
    gal_label_clump_significance: measure significance of all clumps in region.
    gal_pdf_name_is_pdf: Returns 1 if given filename is PDF.
    gal_pdf_suffix_is_pdf: Returns 1 if given suffix is PDF.
    gal_pdf_write: Writes a dataset into an PDF file.
    gal_pointer_allocate_mmap: Allocate space in a file, not in RAM.
    gal_qsort_index_single_d: Sort indexs of single array in decreasing order.
    gal_qsort_index_single_i: Sort indexs of single array in decreasing order.
    gal_qsort_index_multi_d: Sort indexs in multiple arrays (different threads).
    gal_qsort_index_multi_i: Sort indexs in multiple arrays (different threads).
    gal_tiff_name_is_tiff: check if name contains a TIFF suffix.
    gal_tiff_suffix_is_tiff: check if suffix is a TIFF suffix.
    gal_tiff_dir_string_read: convert a string to a TIFF directory number.
    gal_tiff_read: Read the contents of a TIFF "directory" to 'gal_data_t'.

** Removed features

  NoiseChisel:
    - Segmentation (and thus the options below) moved to the new Segment
      program: --onlydetection, --segsnminarea, --checkclumpsn, --segquant,
      --keepmaxnearriver, --gthresh, --minriverlength, --objbordersn,
      --grownclumps, --checksegmentation.

    --skysubtracted: no longer necessary, included in noise measuremnts.

  MakeCatalog:
    --skysubtracted: no longer necessary, included in noise measuremnts.

  Library:
    - The macros 'GAL_STATISTICS_SORTED_NOT',
      'GAL_STATISTICS_SORTED_INVALID', 'GAL_STATISTICS_SORTED_INCREASING',
      'GAL_STATISTICS_SORTED_DECREASING': these macros are removed because
      we already have the 'GAL_DATA_FLAG_SORT*'' bit-flags in 'gal_data_t'.


** Changed features

  Arithmetic:
    - filter-mean: a blank value in the input can be non-blank in the
         output when non-blank elements present in filter.
    - filter-median: similar to filter-mean.

  Fits:
    --history: can be called/written multiple times in one run.
    --comment: can be called/written multiple times in one run.

  MakeCatalog:
    - The 'WCLUMPS' keyword in the objects labeled image is no longer used
         to see if a clumps catalog should also be made. To build a clumps
         catalog, you can now use the '--clumpscat' option.
    - Estimation of noise-level is now done per-pixel over the whole
         label. Until now the average noise level was used.
    --objectsfile has been removed. The main input argument is now assumed
         to be the objects file.

  NoiseChisel:
    From this release, NoiseChisel is only in charge of detection and won't
    do segmentation any more. The new Segment program is in charge of
    segmentation. Many of the changes below are due to this new limited
    scope of NoiseChisel.
    --kernel: value 'none' will disable convolution.
    - Renamed options:
      --convolvedhdu ==> --chdu
      --wkhdu        ==> --whdu
      --detsnminarea ==> --snminarea
      --checkdetsn   ==> --checksn
      --detquant     ==> --snquant
    - By default the output detection map is a binary image (values of 0 or 1).
    - With no output name, the output has a '_detected.fits' suffix.

  Segment:
    - [Previously in NoiseChisel]: For finding true clumps, the difference
      in the peak of the clump and the highest valued river pixel, divided
      by the noise standard deviation are used. Until now, the total
      signal-to-noise ratio was used as a criteria. In initial tests, this
      algorithm was much more promising in detecting clumps over strong
      gradients and also on flatter gradients.

  Table:
    --column: multiple columns (comma separated) can be used in one
         instance of this option (multiple instances of this option are
         still acceptable also).

  Libraries:
    gal_binary_holes_fill: new name for 'gal_binary_fill_holes'.
    gal_dimension_is_different: new name for 'gal_data_dsize_is_different'.
    gal_fits_img_read: now only reads the data not the WCS, therefore it no
        longer needs the last two arguments. A subsequent call to
        'gal_wcs_read' can be used to read the WCS information in the file.
    gal_pointer_increment: new name for 'gal_data_ptr_increment'.
    gal_pointer_num_between: new name for 'gal_data_ptr_dist'.
    gal_pointer_allocate: replaces 'gal_data_malloc_array' and
        'gal_data_calloc_array', through an argument you can ask for the
        allocated memory to be cleared or not.
    gal_qsort_TYPE_i: new name for gal_qsort_TYPE_increasing.
    gal_qsort_TYPE_d: new name for gal_qsort_TYPE_decreasing.
    gal_statistics_is_sorted: can now also update the bit-flags regarding
        the sorted nature of the input (to optimize future calls to the
        function).
    gal_statistics_quantile_function: returns 'inf' or '-inf' if the given
        value is smaller than the minimum or larger than the maximum of the
        input dataset's range. Until now, it would return blank in such
        cases.
    gal_statistics_number: the output dataset now has a 'size_t' type. Until
        now it was 'uint64_t'.

** Bugs fixed

  bug #50957: --version output not possible on Mac OS X
  bug #52979: Many unused result warnings for asprintf in some compilers.
  bug #53122: Configure time CPPFLAGS and LDFLAGS don't pass to BuildProgram.
  bug #53142: Crash when printing values with the '--onlyversion' option.
  bug #53147: NULL value of onlyversion option causing a crash.
  bug #53226: Match output directory ignored when making multiple files.
  bug #53230: Statistics program bad results on integer columns with limits.
  bug #53268: NoiseChisel crash when no growth is possible.
  bug #53295: MakeCatalog parses area larger than clump.
  bug #53304: NoiseChisel crash when there is no detection.
  bug #53312: Fits crash on keyword editing (except --delete).
  bug #53407: Instrumental noise in MakeNoise should be squared.
  bug #53424: Sigma-clipping seg-faults when there are no more elements.
  bug #53580: Warp crash when no WCS present.
  bug #53825: NoiseChisel not accounting for fully zero-valued tiles.






* Noteworthy changes in release 0.5 (library 3.0.0) (2017-12-22) [stable]

** New features

  Manual/Book: An extended tutorial is added showing some general
  applications of almost all the programs. This may be a good place to get
  a feeling of how Gnuastro is intended to be used and some of the
  programs.

  New Program and library: Match is a new program that will match two given
  inputs (currently catalogs). Its output is the re-arranged inputs with
  the same number of rows/records such that all the rows match. The main
  work is also done with the new low-level 'gal_match_catalog' library
  function which can also be used in more generic contexts.

  All programs: a value of '0' to the '--numthreads' option will use the
  number of threads available to the system at run time.

  Arithmetic: The new operators 'filter-median' and 'filter-mean' can be
  used to filter (smooth) the input. The size of the filter can be set as
  the other operands to these operators.

  BuildProgram: The new '--la' option allows the identification of a
  different Libtool '.la' file for Libtool linking information.

  BuildProgram: The new '--deletecompiled' option will delete the compiled
  program after running it.

  CosmicCalculator: all the various cosmological calculations can now be
  requested individually in one line with a specific option added for each
  calculation (for example '--age' or '--luminositydist' for the age of the
  universe at a given redshift or the luminosity distance). Therefore the
  old '--onlyvolume' and '--onlyabsmagconv' options are now removed. To
  effectively use these new features, please review the "Invoking
  CosmicCalculator" section of the book.

  Fits: when an extension/HDU is identified on the command-line with the
  '--hdu' option and no operation is requested, the full list of header
  keywords in that HDU will be printed (as if only '--printallkeys' was
  called).

  MakeCatalog: physical nature agnostic WCS column names. Previously the
  first WCS axis was always assumed to be RA and the second DEC. So for
  example even if you had a spectrum (with X and wavelength as the two WCS
  dimensions), you would have to ask for '--ra' and '--dec'. The new '--w1'
  and '--w2' options are now generic and don't assume any particular type
  only their order in the FITS header. MakeCatalog now also uses the CTYPE
  and CUNIT keywords to set the names and units of its output columns. The
  '--ra' and '--dec' options are now just internal aliases for '--w1' or
  '--w2' which will be determined based on the input's CTYPE keyword. Also
  the new '--geow1', '--geow2', '--clumpsw1', '--clumpsw2',
  '--clumpsgeow1', '--clumpsgeow2' options replace the old options
  '--geora', '--geodec', '--clumpsra', '--clumpsdec', '--clumpsgeora',
  '--clumpsgeodec'. No alias is currently defined for the latter group.

  MakeCatalog: the new '--uprange' option allows you to specify a range for
  the random values around each object. This is useful when the noise
  properties of the dataset vary gradually and sampling from the whole
  dataset might produce biased results.

  NoiseChisel: with the new '--convolved' and '--convolvedhdu' options,
  NoiseChisel will not convolve the input any more and use the given
  dataset instead. In many cases, as the inputs get larger, convolution is
  the most time consuming step of NoiseChisel. With this option, you can
  greatly speed up your tests (to find the best parameters by varying them,
  for a given analysis). See the book for more information and examples.

  NoiseChisel: with the new '--widekernel' option it is now possible to use
  a wider kernel to identify which tiles contain signal. The rest of the
  steps (identifying the quantile threshold on the selected tiles and etc)
  are done on the dataset convolved with '--kernel' as they were
  before. Since it is time consuming, this is an optional feature.

  NoiseChisel: with the new '--qthreshtilequant' option, it is now possible
  to discard high-valued (outlier) tiles before estimating qthresh over the
  whole image. This can be useful in detecting very large diffuse/flat
  regions that would otherwise be detected as background (and effectively
  removed).

  NoiseChisel: the finally selected true detections are now grown based on
  signal contiguity, not by blind dilation. The growth process is the same
  as the growing of clumps to define objects. Only for true detections, the
  growth occurs in the noise. You can configure this growth with the
  '--detgrowquant' and '--detgrowmaxholesize'. With this new feature it is
  now possible to detect signal out to much lower surface brightness limits
  and the detections don't look boxy any more.

  Cosmology library: A new set of cosmology functions are now included in
  the library (declared in 'gnuastro/cosmology.h'). These functions are
  also used in the CosmicCalculator program.

  'gal_table_read' can now return the number of columns matched with each
  input column (for example with regular expressions), a new argument has
  been added to allow this feature.

  'gal_fits_key_img_blank': returns the value that must be used in the
  BLANK keyword for the given type as defined by the FITS standard.

  'gal_txt_write' and 'gal_fits_tab_write' now accept an extension name as
  argument to allow a name for the FITS extension they write.

  'gal_box_bound_ellipse_extent' will return the maximum extent of an
  ellipse along each axis from the ellipse center in floating point.

** Removed features

  Installation: The '--enable-bin-op-*' configuration options that were
  introduced in Gnuastro 0.3 have been removed. By managing the arithmetic
  functions in a better manner (a separate source file for each operator),
  compilation for all types (when done in parallel) takes about the same
  time as it took with the default (only four) types until now.

  MakeCatalog: '--zeropoint' option doesn't have a short option name any
  more. Previously it was '-z' which was confusing because '-x' and '-y'
  were used to refer to image coordinate positions.

  NoiseChisel: The '--dilate' and '--dilatengb' options have been
  removed. Growing of true detections is no longer done through dilation
  but through the '--detgrowquant' and '--detgrowmaxholesize' options (see
  above).

** Changed features

  CosmicCalculator: The redshift is no longer mandatory. When no redshift
  is given, it will only print the input parameters (cosmology) and abort.

  MakeCatalog: when the output is a FITS file, the two object and clumps
  catalogs will be stored as multiple extensions of a single file. Until
  now, two separate FITS files would be created. Plain text outputs are the
  same as before (two files will be created).

  'gal_binary_fill_holes' now accepts a 'connectivity' and 'maxsize'
  argument to specify the connectivity of the holes and the maximum size of
  acceptable holes to fill.

  'gal_fits_img_read' and 'gal_fits_img_read_to_type' now also read the WCS
  structure of the extension/HDU in a FITS file and have two extra
  arguments: 'hstartwcs' and 'hendwcs'. With these options it is possible
  to limit the range of header keywords to read the WCS, similar to how
  they are used in 'gal_wcs_read'.

  'gal_txt_write', 'gal_table_write_log', 'gal_fits_tab_write' and
  'gal_txt_write' don't have the 'dontdelete' argument any more. The action
  they take if the file already exists depends on the file: for FITS, a new
  extension will be added and for text, they will abort with an error.

  'gal_tile_block_write_const_value' and 'gal_tile_full_values_write' now
  accept a new 'withblank' option to set all pixels that are blank in the
  tile's block to be blank in the check image.

  'gal_wcs_pixel_area_arcsec2' will return NaN (instead of aborting) when
  input is unreasonable (not two dimensions or not in units of degrees).

  'gal_wcs_world_to_img' and 'gal_wcs_img_to_world': Until now, these two
  WCS conversion functions would explicitly assume RA and Dec and work
  based on input arrays (so for example it was also necessary to give the
  number of elements and etc). They now accept 'gal_data_t' as input for
  the input coordinates, thus their API has been greatly simplified and
  their functionality increased.

** Bugs fixed

  ConvertType crash when changing values (bug #52010).

  Arithmetic not accounting for integer blank pixels in binary operators
  (bug #52014).

  NoiseChisel segfault when memory mapping to a file (bug #52043).

  CFITSIO 3.42 and libcurl crash at Gnuastro configure time (bug #52152).

  MakeCatalog crash in upper-limit with full size label (bug #52281).

  NoiseChisel leaving unlabeled regions after clump growth (bug #52327).

  Arithmetic crash with no input tokens (bug #52422).

  Libtool checks only in non-current directory (bug #52427).





* Noteworthy changes in release 0.4 (library 2.0.0) (2017-09-13) [stable]

** New features

  All programs: '.fit' is now a recognized FITS file suffix.

  All programs: ASCII text files (tables) created with CRLF line
  terminators (for example text files created in MS Windows) are now also
  readable as input when necessary.

  Arithmetic: now has a new '--globalhdu' ('-g') option which can be used
  once for all the input images.

  MakeNoise: with the new '--sigma' ('-s') option, it is now possible to
  directly request the noise sigma or standard deviation. When this option
  is called, the '--background', '--zeropoint' and other option values will
  be ignored.

  MakeProfiles: the new '--kernel' option can make a kernel image without
  the need to define a catalog. With this option, a catalog (or
  accompanying background image) must not be given.

  MakeProfiles: the new '--pc', '--cunit' and '--ctype' options can be used
  to specify the PC matrix, CUNIT and CTYPE world coordinate system
  keywords of the output FITS file.

  MakeProfiles: the new 'distance' profile will save the radial distance of
  each pixel. This may be used to define your own profiles that are not
  currently supported in MakeProfiles.

  MakeProfiles: with the new '--mcolisbrightness' ("mcol-is-brightness")
  option, the '--mcol' values of the catalog will be interpretted as total
  brightness (sum of pixel values), not magnitude.

  NoiseChisel: with the new '--dilatengb' option, it is now possible to
  identify the connectivity of the final dilation.

  Library: Functions that read data from an ASCII text file
  ('gal_txt_table_info', 'gal_txt_table_read', 'gal_txt_image_read') now
  also operate on files with CRLF line terminators.

** Removed features

** Changed features

  Crop: The new '--center' option is now used to define the center of a
  single crop. Hence the old '--ra', '--dec', '--xc', '--yc' have been
  removed. This new option can take multiple values (one value for each
  dimension). Fractions are also acceptable.

  Crop: The new '--width' option is now used to define the width of a
  single crop. Hence the old '--iwidth', '--wwidth' were removed. The units
  to interpret the value to the option are specified by the '--mode'
  option. With the new '--width' option it is also possible to define a
  non-square crop (different widths along each dimension). In WCS mode, its
  units are no longer arcseconds but are the same units of the WCS (degrees
  for angles). '--width' can also accept fractions. So to set a width of 5
  arcseconds, you can give it a value of '5/3600' for the angular
  dimensions.

  Crop: The new '--coordcol' option is now used to determine the catalog
  columns that define coordinates. Hence the old '--racol', '--deccol',
  '--xcol', and '--ycol' have been removed. This new option can be called
  multiple times and the order of its calling will be used for the column
  containing the center in the respective dimension (in FITS format).

  MakeNoise: the old '--stdadd' ('-s') option has been renamed to
  '--instrumental' ('-i') to be more clear.

  MakeProfiles: The new '--naxis' and '--shift' options can take multiple
  values for each dimension (separated by a comma). This replaces the old
  '--naxis1', '--naxis2' and '--xshift' and '--yshift' options.

  MakeProfiles: The new '--ccol' option can take the center coordinate
  columns of the catalog (in multiple calls) and the new '--mode' option is
  used to identify what standard to interpret them in (image or
  WCS). Together, these replace the old '--xcol', '--ycol', '--racol' and
  '--deccol'.

  MakeProfiles: The new '--crpix', '--crval' and '--cdelt' options now
  accept multiple values separated by a comma. So they replace the old
  '--crpix1', '--crpix2', '--crval1', '--crval2' and '--resolution'
  options.

  'gal_data_free_contents': when the input 'gal_data_t' is a tile, its
  'array' element will not be freed. This enables safe usage of this
  function (and thus 'gal_data_free') on tiles without worrying about the
  memory block associated with the tile.

  'gal_box_bound_ellipse' is the new name for the old
  'gal_box_ellipse_in_box' (to be more clear and avoid repetition of the
  term 'box'). The input position angle is now also in degrees, not
  radians.

  'gal_box_overlap' now works on data of any dimensionality and thus also
  needs the number of dimensions (elements in each input array).

  'gal_box_border_from_center' now accepts an array of coordinates as one
  argument and the number of dimensions as another. This allows it to work
  on any dimensionality.

  'gal_fits_img_info' now also returns the name and units of the dataset
  (if they aren't NULL). So it takes two extra arguments.

  'gal_wcs_pixel_scale' now replaces the old 'gal_wcs_pixel_scale_deg',
  since it doesn't only apply to degrees. The pixel scale units are defined
  by the units of the WCS.

  'GAL_TILE_PARSE_OPERATE' (only when 'OTHER' is given) can now parse and
  operate on different datasets independent of the size of allocated block
  of memory (the tile sizes of 'IN' and 'OTHER' have to be identical, but
  not their allocated blocks of memory). Until now, it was necessary for
  the two blocks to have the same size and this is no longer the case.

** Bugs fixed

  MakeProfiles long options on 32bit big endian systems (bug #51341).

  Pure rotation around pixel coordinate (0,0) (bug #51353).

  NoiseChisel segfault when no usable region for sky clumps (bug #51372).

  Pixel scale measurement when dimension scale isn't equal or doesn't
  decrease (bug #51385).

  Improper types for function code in MakeProfiles (bug #51467).

  Crashes on 32-bit and big-endian systems (bug #51476).

  Warp's align matrix when second dimension must be reversed (bug #51536).

  Reading BZERO for unsigned 64-bit integers (bug #51555).

  Arithmetic with one file and no operators (bug #51559).

  NoiseChisel segfault when detection contains no clumps (bug #51906).

  Correct size checking when allocating gal_data_t (bug #52544).



* Noteworthy changes in release 0.3 (library 1.0.0) (2017-06-01) [stable]

  This is a full re-write of Gnuastro. Most importantly, Gnuastro now has a
  new generic data container ('gal_data_t'). This new container can now
  deal natively with all standard numeric data types, work in RAM or
  HDD/SSD, keep data in any dimensions and has enabled many other very
  useful features. Some of the most prominent of the new features are
  discussed below. It is strongly recommended to review the respective
  section of the Gnuastro manual/book for a better feeling of all the new
  features.

  As discussed below, some program names have changed, if you have a
  previous version of Gnuastro installed from source, it is recommended to
  uninstall it first (with 'make uninstall' using the corresponding
  tarball), then install this new version. Building Gnuastro can be slow,
  so please build in parallel with Make's '-j8' option (to build on 8
  threads).

** New programs or library features

  Library functions that deal with datasets now use this generic data
  container for inputs and outputs, significantly simplifying their
  API. Nearly all library functions have been re-written with much more
  clear names, argument lists and individual purpose. Some example library
  functions are shown below, also see the "Library demos" section of the
  book for some complete working example:

     -- 'gal_table_read' and 'gal_table_write' will read and write data to
        plain text, FITS ASCII and FITS Binary formats.

     -- 'gal_fits_img_read' and 'gal_fits_img_write' can read a FITS image
        to memory or write a FITS image from memory.

  Gnuastro now defines a simple comment line format to keep basic
  information in a plain text table, see the "Gnuastro text table format"
  section of the book. In short for every column, a comment line like below
  can be used to give a name, units, comments, or a type to a column. This
  allows a FITS binary table for example to be written to plain text and
  converted back to binary without loosing any information (except for very
  small floating point errors if not enough decimals are printed).

      # Column N: NAME [UNIT, TYPE, BLANK] COMMENT

  The new Fits program replaces the old Header program. But besides
  reading/checking FITS header keywords, it can now also work on FITS
  extensions/HDUs. For example with no options, it will list all the HDUs
  in a FITS file along with basic information. It can copy a whole HDU to
  another file, or delete a HDU from a FITS file. To get the previous
  behavior of listing all the keywords in a FITS HDU, you can run it with
  the '-p' option.

  All programs now write data into the second HDU of a FITS file to allow a
  clean first HDU. Note that following CFITSIO, HDU counting still starts
  from zero, so FITS images and tables written by Gnuastro in a new file
  can always be accessed with the '--hdu=1' option (which is now the
  default).

  If any program is run within a Git version controlled directory, a
  'COMMIT' header keyword will be added to the created FITS files, see the
  "Output headers" section of the book for a discussion on the usefulness
  of this new feature.

  BuildProgram: a new program to easily compile, link and run a C program
  you have written with Gnuastro's libraries without having to worry about
  which libraries (Gnuastro dependencies) your program needs. Debugging
  ('-g'), optimizations ('-O'), warnings ('-W'), include search path
  ('-I'), link search path ('-L'), and linked libraries ('-l') compiler
  options are also supported. BuildProgram will greatly facilitate the easy
  usage of Gnuastro's libraries.

** Removed programs or library features

  The following program names have been renamed:

    ImageCrop       --> Crop
    ImageWarp       --> Warp
    ImageStatistics --> Statistics
    Header          --> Fits

  SubtractSky has been removed. The Statistics program now has tools to
  estimate the Sky value and it can be subtracted with Arithmetic.

** New features

  All Gnuastro programs that read and write tables can now do so in plain
  text table format or in FITS ASCII or FITS Binary tables. Depending on
  the filename or with the new '--tableformat' common option to all
  programs.

  The option management system in all Gnuastro programs has been completely
  re-written with many new features, some of the most important ones are
  listed below. For developers, you will notice that there is no more usage
  of macros and adding new options has become much more easier.

     -- All programs will now also look for a 'gnuastro.conf' configuration
        file to keep common options for all programs in every directory.

     -- The '--lastconfig' option can be used on the command-line or in any
        configuration file to stop parsing any further configuration files.

     -- The '--config' option can now be used to identify any arbitrary
        file to be parsed as a configuration file. Any file that is given
        to this option is parsed immediately.

     -- The '--printparams' option now also prints the short documentation
        of each option (same description in '--help') after its value.

  It is now possible to choose columns in tables based on column names as
  well as column numbers. It is also possible to search for columns based
  on searching in their units or comments. When using column numbers,
  counting now starts from 1 (one), not 0 (as before). See the new
  "Selecting table columns" section for more on these new features.

  Where relevant, all programs now accept a '--type' option that you can
  use to specify the numerical datatype of the output.

  With the new common option '--minmapsize', you can specify a minimum size
  of an array (in bytes) to store data in SSD/HDD and not in RAM. This can
  be instrumental when you are dealing with large datasets, or even smaller
  ones, but when your RAM is getting full.

  Making a log file is now optional and users have to explicitly ask for it
  with the '--log' option.

  Slower building of Gnuastro: Binary operators (e.g., plus or multiply)
  are now done in the native type of the input dataset. Doing so for all
  the different combinations of types, greatly slows down the initial
  compilation of Gnuastro (after running 'make'). So for every type there
  is now a '--enable-bin-op-*' configure time option. When the dataset's
  type isn't compiled (only for the binary operators), it will be converted
  to a compiled type and then converted back in the end.

  Arithmetic: all operations are done in the native data type of the
  dataset. Until now, it would convert the data internally to double
  precision floating point, do the requested operation and write the data
  back in the proper type. So this new implementation is much more
  efficient.

  Arithmetic: two new classes of operators: type conversion operators to
  all standard types and integer-only operators (all C bit-wise operators
  and the modulo operator).

  ConvertType: can also print the input dataset to the command-line
  ('stdout'). To use this feature set the output filename to 'stdout'.

  Convolve now has the '--minsharpspec' option to specify the minimum
  spectrum value to use in deconvolution (matching PSFs).

  Crop: when in WCS mode it can still only work on aligned images. However,
  very small floating point errors in writing the WCS (for example 10e-13
  degrees) are now acceptable. Until now these would cause Crop to complain
  and abort.

  Crop: the name of the crop can be pre-determined based on the values in a
  given in a table column. This allows your object's IDs to be directly
  used as the crop's file name for example.

  MakeCatalog now also reports the surface brightness in
  mag/arcsec^2. Until now, MakeCatalog would only print the dataset's
  surface brightness in units of magnitudes/pixel. But that is not nicely
  comparable to other datasets. Hence, using a simple calculation (from the
  pixel projected size, fully derived in the book), it now also reports the
  surface brightness in magnitudes/arcsec^2 also.

  MakeProfiles: Profile codes now start from '1' (until now they started
  from '0').

  MakeProfiles: now accepts the radial function of profiles as
  human-readable strings instead of a code for each profile (which was very
  cryptic, although codes are also still acceptable). For example in the
  profile column you can now write 'sersic' instead of the code '1'.

  NoiseChisel: the new '--cleandilated' option will remove dilated objects
  that have a low S/N (it is mainly useful on very clean or mock images).
  For non-clean noise, it will result in a decrease of completeness. With
  this new option, NoiseChisel will also print detection S/N values when
  run with the '--checkdetsn' option.

  Statistics: now reads table columns as well as images and does basic
  operations on them. It can also only work on a certain range of the data
  (instead of the whole set). Alternatively, you can define the range on
  another reference column, but use values of the main column.

  Statistics: all its single-valued measurements can now be done on a
  tessellation (tile grid) over the input dataset.

  Statistics: can now estimate the Sky value on the input dataset using the
  mode's quantile similar to what NoiseChisel does to find its initial
  threshold.

  Statistics: has several new single valued calculations: '--quantile',
  '--quantfunc' (quantile function), '--mode', '--modequant', '--modesym',
  and '--modesymvalue'.

  Warp: align the image with the celestial coordinates using the '--align'
  option.

  Warp: standard modular warpings can now be requested without an input
  matrix, using the following options: '--shear', '--flip', '--project',
  '--rotate', '--scale', '--translate'. Any number of these transformations
  (along with the '--align' option) can be called on the command-line and
  they will be applied in the same order to create one warping matrix. By
  default the WCS will also be corrected.

** Changes in behavior

  Mask image options have been removed from all programs. Instead, all
  programs can work directly on data with blank values. So when some pixels
  must be masked, the Arithmetic program's 'where' operator can be used to
  select special pixels and set them to blank. In particular bit-wise
  operations are now available in Arithmetic to use bit-mask
  images. Managing all these different choices in every program would only
  confuse the user (with too many options).

  Arithmetic: the 'x' letter is now used to represent the multiplication
  operator. Previously it was '*' which needed quotation and was thus very
  inconvenient.

  Convolve: the old '--frequency' and '--spatial' options have been removed
  and are replaced by '--domain' which accepts values of 'frequency' and
  'spatial'.

  Convolve: the old '--viewfreqsteps' was changed to '--checkfreqsteps' to
  fit with the general style of such check images in all Gnuastro's
  programs.

  Crop: '--section' syntax is now inclusive in both bounds.

  Crop: only checks if the center of a crop is filled when the crop was
  defined by its center (for example with '--ra' and '--dec'). The verbose
  outputs of Crop are also not cryptic 0s or 1s. The are human readable
  text.

  Crop: doesn't have separate '--imgmode' and '--wcsmode' options any
  more. There is now a single '--mode' option which accepts values of 'img'
  or 'wcs'.

  MakeProfiles: the old '--inputascanvas' is now called '--clearcanvas'.

  MakeProfiles: until now, it would abort with an error when the input
  columns had blank values. But for masking, it might happen that you set a
  blank magnitude. So this check has now been removed when reading the
  magnitude column.

  NoiseChisel: default value of the '--minskyfrac' option (new name for the
  old '--minbfrac') is now 0.7 as opposed to 0.5. This will allow much
  better estimation of noise properties (by default). It may be slightly
  too high for a crowded field, but the users can change it on the
  command-line (or in a configuration file) for such datasets.

  NoiseChisel: when it is run with any of the '--check' options, it will
  abort after all the check images have been created. This is very useful
  for checking your parameters until each step and not be distracted (or
  have to wait) for later steps to finish.

  Statistics: will not make a histogram and cumulative frequency files, or
  calculate sigma-clipped results by default (with no options). It will
  just print some basic information.

  Table: Previously, if a column was requested, the '-i' option would be
  ignored. But it often happens that the users forget a column name after
  already typing several of their desired columns. So the opposite behavior
  is preferred. Because when more than a couple of columns are needed, you
  will probably forget the column identifiers of the last few and having to
  retype everything is very frustrating. Something like how '--help' takes
  precedence over all other options.

  Table: to select column(s) by regular expression searching, the name now
  has to be put in '/ /' (similar to AWK). If a value isn't in '/ /', the
  programs will only select a column with the exact match.

  Warp: when a 2 by 2 matrix is given, the FITS pixel positions (which
  define the center of a pixel as an integer) are automatically implemented
  internally, see "Invoking Warp" in the manual for more.

  Warp: the old '--nofitscorrect' option has been changed to
  '--centeroncorner' to be more clear. The new option is now more general
  than before and also works on warping with a matrix, not just on modular
  warpings.

  Warp: the old '--nowcscorrection' option has been given a more clear name
  of '--keepwcs'. With this option, Warp will not apply the warp the
  input's WCS structure.

  Warp: the old '--maxblankfrac' option has been changed to
  '--coveredfrac'. Until now, Warp would only look for the fraction of
  input blank/NaN pixel area over the output pixel. But this would be
  useless on the edges of the image. So the new '--coveredfrac' option
  takes the acceptable fraction of output pixel area that must be covered
  by input pixels in order to give that output pixel a value. You can use
  this to set edge pixels that are not fully covered in the new grid to
  blank and have a flat warped image.

** Bugs fixed

  Using '%zu' to print 'size_t' variables for clean build on 32-bit
  systems.

  Crash in Table for some operating systems due to memory is now fixed (bug
  #49347).

  Table's man-page is now created and installed (bug #49418).

  Fixes in the documentation (sr #109170, bug #49419).

  Check for malloc returning valid pointer (bug #49459).

  Segfault in mesh interpolation corrected (bug #49588).

  Corrected bad status usage in calls to wcsp2s and wcss2p (bug #49752).

  Stricter checking in Crop's polygon point list (bug #48978).

  Correction in alignment and getting pixel scale (bug #50072).

  Decomposing PCi_j and CDELTi matrices in output WCS (bug #50073).

  Using image naxes[n] when checkcenter is larger (bug #50099).

  Memory leak in MakeCatalog corrected (bug #51118).

  Fix copy-paste error in MakeCatalog flag arrays (bug #51130).





* Noteworthy changes in release 0.2 (library 0.0.0) (2016-10-03) [stable]

** Bugs fixed

  Linker errors on some operating systems have been fixed (bug #48076).

  Several memory allocation, checks or redundancies have been fixed: bugs
  #48453, #48516, #48603, #48611, #48571, #48650, #48657, #48692, #48770,
  #47866, #48899, #49049, #49007.

  ImageCrop no longer crashes with very long output file names (bugs #46241
  and #45380).

** New programs or headers

  Table: a new utility to read and write FITS binary and ASCII tables. It
  can also print the column information or select columns using regular
  expressions (task #13579).

  Shared libraries and headers are now installed. The libraries can be used
  in C and C++ programs. This release includes the following headers:
  'gnuastro.h', 'array.h', 'box.h', 'fits.h', 'linkedlist.h', 'mesh.h',
  'polygon.h', 'qsort.h', 'spatialconvolve.h', 'statistics.h', 'threads.h',
  'wcs.h', 'txtarray.h' (task #13765).

  Gnuastro now comes with a script in its top source directory
  ('tmpfs-config-make') to configure and build it in the tmpfs (on the
  RAM), for those systems that have it. See the new "Configure and build in
  RAM" section in the book for more (task #14100).

** New features

  MakeProfiles also accepts WCS positions (task #13566).

  Flat profiles in MakeProfiles can be given a profile specific value. The
  new '--mforflatpix' option MakeProfile will use the value in the
  magnitude column as a fixed value for each pixel. This can be very useful
  in defining a mask, or creating segmentation maps or labeled images (task
  #14115).

  MakeProfiles can now use input image as canvas. Instead of specifying the
  WSC and image size parameters manually. With the new '--inputascanvas'
  option, MakeProfiles will get this information (along with blank pixels)
  from an already existing image (task #14116).

  Type of output in MakeProfiles and Arithmetic can be specified with the
  '--type' option.

  Magnitude error column in MakeCatalog with the '--magnitudeerr' option.

  Arithmetic now has new conditional (task #13870) and logical operators
  (task #14153) along with an operator for actions only when conditions are
  true: 'where'. The new 'isblank' operator will also enable you to select
  blank, or masked, pixels (task #14146).

  The '--noerodequant' in NoiseChisel enables it to detect small and
  sharper profiles by disabling erosion on pixels above a certain quantile
  (task #14139).

  MakeCatalog can also calculate the upper limit magnitude for each given
  object in the image by randomly positioning the object's footprint over
  undetected regions of the image (task #14167).

  The source tarball is now also distributed with Lzip for a much better
  compression ratio and more robust archival file format.

** Changes in behavior

  The two MakeProfiles options '--setconsttonan', '--setconsttomin' have
  been removed (see '--mforflatpix' above for their alternative).

  MakeCatalog makes clump catalog only when asked (when the 'WCLUMPS'
  header exists in the objects HDU). This can be very useful in cases like
  aperture photometry, when the object labels are not generated by
  NoiseChisel and so a clump image doesn't exist (task #14122).

  Default cosmological parameters in CosmicCalculator set to Plank 2015
  results: A&A (2016), 594, A13 (arXiv 1502.01589).

  The '--envseed' option (to read random number generator type and seed
  from the environment) to MakeProfiles and MakeNoise can also be given in
  the configuration files.





* Noteworthy changes in release 0.1 (2016-05-30) [stable]

** Bugs fixed

  MakeCatalog's problem in checking the sizes of all input images is now
  fixed.

  NoiseChisel's problem with reading the '--kernel' option is now
  corrected (bug #46750).

  lib/mesh.c's problem in correctly calculating the mesh sizes was
  corrected (bug #47611).

  'make check' will not look into system utility configuration files. In
  the previous release, if Gnuastro was already installed, the
  configuration files already present on the system would also be read. Now
  only configuration files in the tested package are used (bug #47833).

  Ghostscript's version is now checked at configure time after its
  existence. ConvertType uses the '-dPDFFitPage' option to Ghostscript
  which was introduced in version 9.10, so older versions would pass
  configure but at 'make check' time, the PDF test would fail. Now this
  test is skipped (bug #47868).

  Most tests would fail when 'make check -jN' was run (to do the checks on
  N threads). A dependency structure has now been defined to fix this
  problem and greatly speed up the testing process (bug #47957).

** New utilities

  Arithmetic: For arithmetic operations on the pixels of input images. With
  this utility, it is now possible to add multiple images with each other,
  or easily calculate a median image. It as a large set of other arithmetic
  operations and some functions which can be done on the input image(s). An
  unlimited number of input images can be given, the images will only be
  loaded when necessary and will be freed as soon as they are no longer
  necessary.

  CosmicCalculator: For doing cosmological calculations at a given
  redshift.

** New features

  All the utilities that would produce a log file now have a '--nolog'
  option to avoid printing a log file.

  The tiled image compression convention (.fits.fz, created with 'fpack')
  files can now be used as input in the utilities.

  ImageCrop can now also crop a polygon from the input image. The polygon
  vertices can be given in the world or image coordinates. The simple
  '--polygon' option will keep the insides of the polygon while the
  '--outpolygon' will keep the outside of the polygon.

  ImageCrop and ImageWarp can now read the WCS information of a FITS header
  from a specific region with the '--hstartwcs' and '--hendwcs'. In some
  older FITS images, when the WCS distortions were not as standardized as
  now, there were cases which would confuse WCSLIB.

  NoiseChisel can now save the grown clumps image instead of the original
  clumps image in the output with the '--grownclumps' option.

  Convolve can now do deconvolution with the '--makekernel' option.

  MakeProfiles now has a '--setconsttonan' option which will fill the
  constant profiles with a NaN (blank) value, not a number, allowing the
  creations of elliptical masked regions for example.

  Header can now import a keyword directly from a string with the '--asis'
  option.

  MakeCatalog can now output the geometric (average position independent of
  pixel flux value) positions of the objects too.

  MakeCatalog can now produce the object's elliptical parameters (for
  example semi-major axis, semi-minor axis, and position angle). This can
  also be done both in standard flux weighted and geometric methods too.

  MakeCatalog now has a '--threshold' function to only use pixels above a
  given threshold in each object or clump. This is useful to avoid diffuse
  regions in calculations.

  MakeCatalog now has a '--noriverbrightness' option. With this option it
  is possible to calculate the clump flux without subtracting the river
  pixels on its circumference.

  The number of CPU threads is no longer a configuration option, it is now
  determined at run-time for each program. Therefore it is now easily
  possible to built Gnuastro on one system to use on another (commonly done
  in the GNU/Linux package managers). Therefore ./configure no longer has a
  '--with-numthreads' option.

  Every commit in Gnuastro's history (after implementing this feature) can
  now be given a unique version number. Since the version number is printed
  in possible outputs, this feature can help reproducibility, even when the
  an official/stable release isn't used.

  The AUTHORS file is now automatically generated from the version
  controlled history. Also all the authors that have contributed to
  Gnuastro are included in the second (copyright) page of the PDF book.

  All the bootstrapped directories are now moved with a new 'bootstrapped'
  directory in the top source directory. This significantly cleans up this
  directory, allowing users to more easily find the hand-written Gnuastro
  source files they like.

  A 'bug-gnuastro' Info page was created so users can easily go to that
  page for information on how to submit bug reports. It is accessible on
  the command line with the command 'info bug-gnuastro'.

** Changes in behavior

  The separate utilities no longer have a separate version number. With the
  introduction of unofficial version numbers generated from each commit in
  Gnuastro's history, the utility version numbers would cause confusion.

  MakeProfiles will now add a suffix to the individual images and put them
  in the output directory if specified.

  NoiseChisel and MakeCatalog now use the median mesh standard deviation to
  define the over-all depth of the image. Previously they used the maximum
  value (or the least depth).

  NoiseChisel no longer outputs a sky subtracted image. This job can now be
  done with the new Arithmetic utility.

  NoiseChisel's '--segsnhistnbins' option was renamed to
  '--clumpsnhistnbins'.

** Improvements

  NoiseChisel's default quantiles were changed to 0.95 from 0.99. Since the
  old value was too severe.

  NoiseChisel's S/N thresholds are now found from the distribution of
  pseudo-detections and clumps from the full image, not within each large
  mesh. This was done to increase the accuracy of the S/N threshold. There
  were commonly not enough points in large mesh sizes and this would add
  scatter. With ImageCrop's polygon capabilities, it is now easily possible
  to cut out the region that has uniform noise properties (depth and
  correlated noise). Therefore the old '--checkdetectionsn' and
  'checkclumpsn' options are no longer present.

  When building from the version controlled source, the whole bootstrapping
  process is done with one script. In the previous version, all the
  separate operations should have been done by hand (as instructed in the
  old manual).

  All the build steps now report what was done and suggest the next
  step. This feature can be disabled with the '--disable-guide-message' at
  configure time.





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Copyright (C) 2015-2025 Free Software Foundation, Inc.

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the terms of the GNU Free Documentation License, Version 1.3 or any later
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