Jan 16  2001:
Changes in drawmap between version 2.2 and version 2.3:

+ This point release is partly the result of downloading more
  test data for more parts of the USA, and fixing whatever new
  problems might show up.  There are, however, several new
  options and general modifications, and also a few bug fixes.
  These are described below, although some of the minor bug
  fixes are omitted.

+ Added the -r option to allow the sharpness of the shaded
  relief to be varied.  The default is fully-shaded relief,
  which was the only available shading in previous releases.
  The new option allows the darkness of shadows to be
  reduced, in steps, until all shading disappears and only
  simple color bands remain.

+ Added the -z option, which adjusts the color table so that
  it exactly spans the range of elevations in the given
  data.  This ensures that all available colors are used in
  the map; but at the cost of having each color represent
  a peculiar range of elevations.

+ Added the -m option, which allows limited enhancement
  of light/dark shading in shaded-relief maps.

+ Added the -t option, to shut off generation of tick
  marks and latitude/longitude markings.

+ In response to a request, added the -C option, which works
  the same as the -c option, except that it fills in the
  space between contour lines with solid colors.

+ In past releases, the -c option located contour lines in
  the centers of the elevation bands.  In other words, if
  the contour interval was 100 meters, then the first contour
  would be at 50 meters, with the next at 150 meters.
  In this release the code has been modified so that contour
  lines are on the edges of the elevation bands.  In other
  words, if the contour interval is 100 meters, then the
  contours are at 100 meters, 200 meters, and so on.

+ A few of the GTOPO30 files were rejected because quantization
  error caused some consistency checking to fail.  Loosened
  up the checks slightly so that the files now pass muster.

+ Updated the color scheme for drawing DLG vector data.
  Changed railroads and pipelines to black, and changed
  vegetative features to green.

+ Added support for more attribute types, including
  190/UNPAVED.  Fixed a few attributes that have special
  cases, such as range and township numbers that can
  take forms like "10 1/2E".

+ Some USGS SDTS DLG files have attributes whose record
  IDs double back and duplicate other record IDs in the file.
  (Wilmington Delaware 24K DLG HY 1379127.HY.sdts.tar.gz
  and 1379151.HY.sdts.tar.gz are examples.)  I would guess
  that this is a bug in the SDTS files, since it would leave
  no way to distinguish between attributes.  (One could use
  the record number in the ISO 8211 header, but I don't
  think this is considered legitimate under the standard.)
  One way or the other, this was causing drawmap some
  indigestion, so the software has been fixed to deal with
  the problem as best it can.  Drawmap prints a warning
  message when this situation occurs.

+ Beefed up the test program, tacked onto the end of
  sdts_utils.c, so that it is a useful viewing tool
  for SDTS files.






Aug  1  2000:
Changes in drawmap between version 2.1 and version 2.2:

+ Added the sdts2dem and sdts2dlg programs to convert
  SDTS transfers into the `classic' DEM and `optional'
  DLG formats.  I wrote these primarily to allow me
  to test drawmap's SDTS capabilities, but they should
  be generally useful.

+ Improved the handling of SDTS files.  In particular,
  we no longer ignore some of the minor attribute files,
  so all attributes should be included.  Improved the
  handling of attributes overall.  This includes
  specific support for attributes with special needs.

+ There were a number of minor repairs and upgrades here
  and there.
  
+ Decreased the default memory footprint a bit, by changing
  some long variables to shorts in some of the larger
  arrays.  Unfortunately, new feature development probably
  devoured a lot of these savings.
  
+ Modified the -h option to automatically include a blue
  surface at sea level.
  
+ Modified the -i option to include the DLG name, and the
  type of data in the file, when printing info about DLG files.





Jul 23  2000:
Changes in drawmap between version 2.0 and version 2.1:

+ Added support for the NAD-83 datum and the WGS-84 datum.

+ Drawmap can now read SDTS-format DEM and DLG files.

+ At the request of a drawmap user, I added GTOPO30
  files to the set of files drawmap can read.  This should
  provide at least some map-drawing capability for people
  who can't get DEM data for their countries of interest.

+ There were a number of minor repairs and upgrades here
  and there.

+ Changed the names of block_dem and block_dlg to unblock_dem
  and unblock_dlg so that they are consistent with the
  equivalent "dd" commands.





Jul  8  2000:
Changes in drawmap between version 1.10 and version 2.0:

+ This was a fairly major restructuring of drawmap, mainly to
  get it to handle DEM and DLG data at the 7.5-minute
  resolution.

+ In past versions of drawmap, data smoothing was done when
  the image resolution and data resolution were the same.
  This version of drawmap no longer smooths when the source
  data and target image have close to the same resolution.
  In addition, the code implementing smoothing has been
  clarified, so that the smoothing behavior should be easier
  to understand and modify.

+ Restructured the shaded relief code to allow it to handle
  data from DEMs in various resolutions.  Also moved most of
  the color definitions into colors.h so that users can more
  easily modify the color scheme.  Provided four separate
  color map tables, selectable by the "-n" option, so that
  users can choose between a variety of color schemes.
  "Natural" colors are now the default, rather than the
  garish high-perception colors used in previous versions.

  Also toned down the red and blue that are used to draw
  streams and roads.  They were a bit distracting.

+ Added a new "-w" option to allow flat sea-level areas to be
  automatically colored blue.

+ Removed the requirement that the x and y dimensions be even.
  This was done primarily because 7.5-minute DEMs often have
  odd dimensions.

+ Drawmap no longer tries to create an image file until after
  most error checking is done.  This should reduce the incidence
  of half-created image files being left behind after an error.

+ Drawmap now uses Redfearn's formulas to convert UTM coordinates
  to latitude/longitude coordinates and vice versa.  However,
  the program still uses linear interpolation from the corners
  of the data blocks to transfer DEM data into the map image.

+ There are two new stand-alone commands, utm2ll and ll2utm that
  convert latitude/longitude coordinates to UTM coordinates and
  vice versa.  They currently only support the NAD-27 datum,
  but can be easily modified to use others.

+ The dem_dlg_info program has been deleted.  It is replaced by
  the "-i" option to drawmap.

+ The height-field program in the height_field subdirectory has
  been deleted.  It is replaced by the "-h" option to drawmap.
  The code that tried to generate "povray" objects for roads,
  lakes, towns, and so on, is no longer present in any form.
  It produced crude results and didn't seem very useful.





Jun 18  2000:
Changes in drawmap between version 1.9 and version 1.10:

+ The USGS has changed the format of both types of GNIS
  files.  Modified drawmap to handle the new formats.
  NOTE:  Files in the old formats will no longer work.

+ Cleaned up a few minor things here and there.





Jun  3  2000:
Changes in drawmap between version 1.8 and version 1.9:

+ Some of the newer USGS 100K DLG files contain newlines.
  (Older ones did not.)
  Modified drawmap to handle this new wrinkle.

+ Provided a new program called dem_dlg_info, to print
  out some useful information from the headers of DEM
  and DLG files.

+ Dropped the block_std program, since standard-format
  files have disappeared from the USGS web site.

+ Added manual pages for block_opt and dem_dlg_info.





Jan  3  2000:
Changes in drawmap between version 1.7 and version 1.8:

+ Clarified the code comments and the manual page for drawmap.

+ Included the povray_height_field directory, which contains
  a modified version of drawmap that will produce information
  that the ``povray'' package can use to make 3-dimensional
  renderings of terrain.

+ There were no changes in the operation of drawmap --- only
  changes in the code comments.  The primary purpose of this
  release was to add the drawmap_height_field program.





Jan 16  1999:
Changes in drawmap between version 1.6 and version 1.7:

+ removed restrictions on the size of contouring intervals

+ added code to allow use on big-endian machines

+ added gaussian smoothing for oversampled maps to reduce checkerboard effect

+ changed DLG line-drawing algorithm to produce better map registration

+ changed drawmap and llsearch to handle the new GNIS format





Dec 11  1998:
Changes in drawmap between version 1.3 and version 1.6:

+ Fixed a portability bug, and an obscure bug in the code that
  draws tick marks at the edges of the image.

+ Added some new information about licensing (see the file "COPYING_NOTE").

+ Added a new option "-c", that draws contour lines instead of the normal
  shaded relief.





Oct 12  1998:
Changes in drawmap between version 1.3 and version 1.5
(there was no version 1.4):

+ Fixed a portability bug, and an obscure bug in the code that
  draws tick marks at the edges of the image.

+ Added some new information about licensing (see the file "COPYING_NOTE").

+ Added a new option "-c", that draws contour lines instead of the normal
  shaded relief.