Utilities for use with SPLAT! software are found under the
utils directory. They include the following:
The srtm2sdf utility generates SPLAT Data Files (SDFs) from STS-99
Space Shuttle Topography Mission (SRTM) 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
Version 2 elevation models contain data "spikes", "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 usgs2sdf derived SDF data (see usgs2sdf below).
If such data is 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.
The srtm2sdf utility processes SRTM-3 3-arc second resolution data
or use with SPLAT! operating in standard definition mode.
SRTM-3 Version 2 Elevation Data files may be downloaded from:
http://dds.cr.usgs.gov/srtm/version2_1/SRTM3/
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 usgs2sdf
derived SDF files 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 either replaced with usgs2sdf-derived SDF data, 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.
The srtm2sdf-hd utility operates in an identical manner as srtm2sdf,
but is used to generate HD SDF files from SRTM-1 one-arc second
resolution data files for use with SPLAT! HD. SRTM-1 data files
are available for the United States and its territories and
possessions, and may be downloaded from:
http://dds.cr.usgs.gov/srtm/version2_1/SRTM1/
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 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.
This utility reads certain U.S. Census Bureau files to produce city/site data files that can be imported into SPLAT! software to annotate SPLAT!-generated maps. Incorporated Places/Census Designated Places data files for use with citydecoder may be downloaded from:
http://web.archive.org/web/20130201115142/http://www.census.gov/geo/www/cob/bdy_files.html
(Formerly: http://www.census.gov/geo/www/cob/bdy_files.html)
Similarly, County Subdivision files containing the names, locations, and boundaries of cities, and smaller towns, townships, and boroughs may be downloaded from:
http://web.archive.org/web/20130331172800/http://www.census.gov/geo/www/cob/cs2000.html
(Formerly: http://www.census.gov/geo/www/cob/cs2000.html)
and processed with the citydecoder utility.
Please select the ARC/INFO Ungenerate (ASCII) Metadata Cartographic Boundary
Files from these sites and unzip them prior to processing them with
citydecoder:
unzip -a pl34_d00_ascii.zip
unzip -a cs34_d00_ascii.zip
U.S. Census files are cataloged by the two digit FIPS code for the region (state) they represent. A list of FIPS codes is included in fips.txt under splat-1.4.1/utils for your convenience.
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 were extracted after the unzipping process, 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
In a similar manner, unzipped County Subdivision files may be processed
with the citydecoder utility to produce a file containing locations and
names of towns, townships, and boroughs:
citydecoder cs34 | sort > townships.nj.dat
citydecoder can also process more than one file or file type per invocation,
and produce a merged output file as follows:
citydecoder pl34 cs34 | sort > everything.in.nj.dat
Be advised that any redundancy that may exist between "cs" and "pl" files will be reflected in the merged output file, so some manual editing of the output file may be necessary.
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
The bearing utility reads a pair of .qth files specified on the command
line, and returns the azimuth bearing and great circle path distance between
the two points specified. A -metric switch is available so that distances
can be provided in kilometers rather than statute miles. SPLAT! provides
similar distance and bearing information between two specific site locations.
The bearing utility, however, provides the information quickly and easily
over great distances without having to run SPLAT!
aw3d30_2_srtmhgt.sh is a support utility used to convert AW3D30 (ALOS Global Digital Surface Model 'ALOS World 3D - 30m) into 30m (1arc second) srtm files which can then be processed by srtm2sdf-hd.
aw3d30_2_srtmhgt.sh -s <srcdir> -d <destdir>
More information on the aw3d30 can be found at https://www.eorc.jaxa.jp/ALOS/en/aw3d30/index.htm