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================
SPLAT! Utilities
================
Utilities for use with SPLAT! software are found under the
splat-1.2.1/utils directory. They include the following:
srtm2sdf
========
The srtm2sdf utility generates SPLAT Data Files (SDFs) from 3-arc second
STS-99 Space Shuttle Topography Mission (SRTM-3) elevation data files.
This data is of a much higher quality than that contained in older USGS
Digital Elevation Models of the same resolution. However, many SRTM-3
Version 2 elevation models contain data "voids" and "wells" that are the
consequence of the radar mapping process.
The srtm2sdf utility has the ability to detect and replace SRTM data
outliers with equivalent SDF data created through the usgs2sdf utility
(below). If equivalent USGS-derived SPLAT Data Files are not available,
SRTM outliers are handled either through adjacent pixel averaging, or by
threshold limiting using user-specified limits. Of all three methods,
the USGS-derived SDF replacement method yields the best results.
SRTM-3 Version 2 Elevation Data may be downloaded from:
ftp://e0srp01u.ecs.nasa.gov:21/srtm/version2/
Files available at this site are ZIP compressed, and must be
uncompressed (using "unzip", or "gunzip -S .zip") prior to being
processed by srtm2sdf.
The srtm2sdf utility accepts command-line options as follows:
-d: used to specify the directory path to the location of existing
SDF files (presumably created at an earlier date through the
usgs2sdf or postdownload utility) that are to be used to replace
outliers found in the SRTM data file. The -d option overrides
the default path specified in your $HOME/.splat_path file.
-n: used to specify the elevation (in meters) below which SRTM data
is replaced. Below this limit, SRTM elevation data is either
replaced using existing SDF equivalent files, or averaged among
adjacent elevation data points. The default threshold for the
replacement limit is sea-level (0 meters). Unless elevations
below sea-level are known to exist for the region being
processed by the srtm2sdf utility, the -n option need not be
specified.
Some examples of srtm2sdf use:
srtm2sdf N40W074.hgt
srtm2sdf -d /cdrom/sdf N40W074.hgt
srtm2sdf -d /dev/null N40W074.hgt (/dev/null prevents USGS data
replacement from taking place)
srtm2sdf -n -5 N40W074.hgt
In all cases, SDF files are written into the current working directory.
The srtm2sdf utility may also be used to convert 3-arc second SRTM data
in Band Interleaved by Line (.BIL) format for use with SPLAT! This data
is available via the web at: http://seamless.usgs.gov/website/seamless/
Once the region of the world has been selected at this site, select the
"Define Download Area By Coordinates" button under "Downloads". Proceed
to request the download of the region(s) desired in 1 degree by 1 degree
regions only, and make sure bounding coordinates entered fall exactly on
whole numbers of latitude and longitude (no decimal fractions of a degree).
Select the "Add Area" button at the bottom.
On the next screen, select "Modify Data Request". On the subsequent screen,
de-select the National Elevation Dataset (NED) format and select "SRTM 3 arc
sec - Shuttle Radar Topography Mission [Finished]". Change the format from
ArcGrid to BIL, and from HTML to TXT.
Select the "Save Changes and Return To Summary" button.
Select the "Download" button, and save the file once it has been sent to
your web browser.
Uncompressing the file will generate a directory containing all files
contained within the downloaded archive. Move into the directory and
invoke srtm2sdf as described above with the filename having the .bil
extension given as its argument. Finally, move or copy the generated
.sdf file to your SPLAT! working directory.
usgs2sdf
========
The usgs2sdf utility takes as an argument the name of an uncompressed
and record delimited Digital Elevation Model Data (DEM) downloaded from
the US Geological Survey, and generates a SPLAT Data File (SDF) compatible
with SPLAT! Software. usgs2sdf may be invoked manually, or via the
postdownload script.
postdownload
============
postdownload is a front-end to the usgs2sdf utility. postdownload
takes as an argument the name of the gzipped Digital Elevation Model
(DEM) downloaded from the US Geological Survey (ie: wilmington-w.gz).
postdownload uncompresses the DEM file, adds necessary record delimiters,
and invokes usgs2sdf to produce a SPLAT Data File (SDF).
USGS Digital Elevation Models may be downloaded from:
http://edcftp.cr.usgs.gov/pub/data/DEM/250/
Invoke postdownload with the name of each DEM file downloaded to
produce a database of SPLAT Data Files.
citydecoder
===========
This utility reads U.S. Census Bureau files of Incorporated Places/Census
Designated Places, and generates city/site data files for use with SPLAT!
software. Files for use with this utility are available for download
free of charge from:
http://www.census.gov/geo/www/cob/bdy_files.html.
Please select the ARC/INFO Ungenerate (ASCII) Metadata Cartographic Boundary
Files from this site and unzip them prior to importing them to citydecoder.
U.S. Census files are cataloged by the two digit FIPS code for the region
(state) they represent. citydecoder takes as an argument the two-letter
file prefix plus the FIPS code of the region or state being processed.
For example:
citydecoder pl34
reads files "pl34_d00.dat" and "pl34_d00a.dat" that are extracted after
the downloaded file has been unzipped, and generates a list of city names
and geographical coordinates for the state of New Jersey (FIPS code 34).
This data may be sorted and written to a file (cities.nj.dat) in the
following manner:
citydecoder pl34 | sort > cities.nj.dat
A list of FIPS codes (fips.txt) is included under splat/utils for your
convenience.
fontdata
========
The fontdata utility reads Slackware gzipped console font data
to create the fontdata.h file required for compilation of SPLAT!.
Font data of the type needed by this utility may be found under
/usr/lib/kbd/consolefonts (Slackware < 8), or under
/usr/share/kbd/consolefonts (Slackware >= 8.0).
A default fontdata.h file is already included in with SPLAT!, and is
a derivative of the s.fnt console font type available under Slackware.
fontdata takes as an argument the name of the file containing the
gzipped compressed console fonts:
fontdata s.fnt.gz
Building The Utilities
======================
Normally, these utilities are built and installed along with SPLAT!
when SPLAT!'s ./configure script is invoked. However, if you modify
them and/or wish to build and install them separately, here is how it's
done. First, invoke the "build" script to compile each or all utilities
in this directory by name. For example:
./build citydecoder
compiles citydecoder only, while
./build all
compiles all utilities.
Installing The Utilities
========================
Invoke the "install" script to install each or all utilities in this
directory by name. For example:
./install citydecoder
installs citydecoder only, while
./install all
installs all utilities.
You need to be 'root' to install any or all of these utilities.
---
John A. Magliacane, KD2BD
August 2007
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