m.dem.extract, m.dem.examine

[Timothy Keitt]

Neither of these programs (m.dem.examine, m.dem.extract) seem to work
properly. I have two DEM's on disk and m.dem.examine gives the wrong
results with both. They are unlabled ascii DEM's dumped to disk from
1/2" tape. I have varified that the header format on both files is
correct according a USGS guide to DEM's. In neither case were CR-LF
sequences added to the file when they were read from tape. I have also
been able to convert these files to VIFF format in the Khoros image
processing system without a hitch.

M.dem.examine reports 8 million+ columns for a file that has only ~350.
It also gives the ns resolution and ew resolution as zero. In one case
it mis-reads the edge coordinates in one of the files, reporting a value
of zero. Dumping the file header shows this to be completely wrong.

I pressed on regardless and tried m.dem.extract. In both cases, this program
reported a maximum and minimum elevation of zero and produced a grass
raster image with all zeros (even though m.dem.examine *did* read the
elevations correctly). Pretty tough to use a GIS when you can't get any
information into it. I think a little quality control is in order.

tkeitt