Ag Leader SMS Basic and Advanced Manual - Manual (Page 157)

Reference Information
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SDTS to DEM Converter (ADVANCED)
The United States Geological Survey (USGS) produces digitally-encoded terrain data in the form of regular grids called
"digital elevation models", or DEM files. Several different file formats have been used for this data, culminating in the
incredibly complex Spatial Data Transfer Standard, or SDTS.
The adoption of SDTS was a giant step backwards. While previous DEM files could be read by relatively simple
programs, SDTS file are difficult to read even with the help of a large external programming library. A conversion tool
was developed by individuals in the private sector for use/distribution in the public domain that converts SDTS data
back to the old DEM format for easier integration into other applications. The program is called SDTS2DEM.exe and is
provided on the software CD for your use in converting to standard DEM files, which the software provides a standard
import for under the File Menu, Import, and Spatial File. DEM's can be used in the software to replace the 3D grid that
is used in the 3D Terrain View to provide higher accuracy and continuity than the grid generated by your log data may
provide.
How to Use the Converter Program
Follow these step to convert a SDTS file set to a DEM file:
1. Find the location of your SDTS DEM data that you have downloaded or purchased. SDTS data is almost
always zipped using the .TAR.GZ zip format and a common file would have a name like
1628494.DEM.SDTS.TAR.GZ. Unzip this file to a location on your computer. The folder it creates when it
unzips will contain a number of *.DDF files which define the SDTS DEM data.
NOTE: If you unpack your file using WinZip, be sure that the "TAR file smart CR/LF conversion"
box is NOT checked on the Options/Configuration/Miscellaneous screen. Also make sure to
unzip each file into its own folder, do not unzip them all into one location because some files
may overwrite each other.
2. Now go to the software CD, and the MISC folder, and then the OTHER folder below that. Copy the
sdts2dem.exe program.
3. Now paste the copied program into each folder(s) that you have SDTS DEM files with the *.DDF extension.
4. Double-click on the sdts2dem.exe program to start it and follow its directions to complete the conversion.
5. Once completed you will end up with a single DEM file that you can now import into the software.