m.dem.extract, m.dem.examine

[Michael Shapiro]

Would you care to rewrite these programs to provide the quality
control?  Short of that, would you provide an exact copy of the disk
image of the dem tape on moon.cecer.army.mil under the incoming
directory (call it m.dem.extract.bad) and we will see why m.dem.extract
can't read it.
|
|
|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
|
|
|
|


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Michael Shapiro                        U.S. Army CERL                  
email:   shapiro at zorro.cecer.army.mil  Environmental Division          
phone:   (217) 352-6511  ext 526       P.O. Box 9005                   
fax:     (217) 373-7222                Champaign, Ill. 61826-9005
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