Converting SDTS (.tar.gz) files into a VPR DEMs Special Note The SDTS DEM files are not converted to VistaPro DEM format. They are still in their original .tar.gz format. You will need a compression utility like WinZip to decompress the .tar.gz into useable files from which you can then convert using our MCNV utility. To convert a SDTS (.tar.gz) file into a VistaPro DEM, follow these steps: When decompressing the files you need to turn off an option in the WinZip configuration. In the Options->Configurations ->Misc tab, there is a checkbox "TAR file smart CR/LF conversion" It is checked by default and needs to be unchecked. When you use WinZip on the .tar.gz file, you should get a dialogue which asks "Archive contains 1 file: xxxx.dem.stds.tar Should WinZip decompress and open to temporary folder?" You should say "yes". If you get any other message beside that then something is not set up correctly. You will be asked to choose a location and name for the SDTS files that are about to be extracted. The resulting files will be .DDF files. It is at this point you use the MCNV conversion utility. Special Note We use WinZip 9.0 for all our compression needs. We are most familiar with this utility so we suggest getting the latest version of WinZip. It is only $30, and well worth it!. Start MCNV and select "open SDTS files" from the File menu. Locate the folder that has the .ddf files you just extracted and open the "CEL0.ddf" file into MCNV. This then processes the .ddf files into a landscape visible in the MCNV window. Select "Save Region" from the File menu. This will convert those SDTS .ddf files into VP DEM files. You will be asked for a save location. By default VP is set to open DEMs with a Sample Spacing of 10 but the higher resolution DEMs that we are creating need to have a higher Sample Spacing. Under the Manipulation tab set the Sample Spacing to 90. We've found this setting to be the most accurate for the Grand Canyon DEMs, but you can change it to anything you like.