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Copyright 2002 by SoftWright LLC
Q: I tried to import an ASCII file that is supposed to be the USGS ASCII DEM format but it did not create the TAP data file. What is the problem?
A: The TAP Topo Utilities module includes a function to import 3-second and 30-meter USGS ASCII DEM (Digital Elevation Model) files.
It is possible that the file you are trying to import has an ASCII carriage-return and line-feed (CR/LF) at the end of each line. (You can tell if you open the file with WordPad and there are readable lines of data visible.)
The TAP Topo Utilities program was written to read the USGS ASCII DEM files for 3-second and 30-meter data as downloaded from the USGS ftp site. Those files do not include the CR/LF at the end of each line. Instead, they contain spaces so each "line" is exactly 1024 characters long. Without the CR/LF, when you open the file in WordPad, what you see is one very long line of information.
If possible, you can see if the source of your data files can provide the files without the CR/LF, with 1024 character record lengths. Then you should be able to read the DEM files with the TAP Topo Utilities without any problem.
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Copyright 2002 by SoftWright LLC