extracting DEM data

Craig A. Miller cmiller at pnwg.wa.com
Tue Nov 23 18:35:34 EST 1993

On Tue, 23 Nov 1993, Gurcharan Khanna wrote:

> hi,
> i have recently installed Grass4.1 on a SunSparc server and have
> started setting up some data layers for los angeles. i have imported
> Tiger files with no problem. But now i can't seem to import DEM files
> with any success.
> 1) is there a tutorial for m.dem.extract or other ways to import DEM files?
> 2) otherwise, here is what i am trying:
> 	a) obtained DEM files from usgs ftp site.
> 	b) start grass set to my LA database
> 	c) use g.region to set region to something slightly larger than
> 	   the header info from the DEM indicates
> 		set res to 00:00:03
> 	b) using m.dem.extract to extract data
> 	   setting start and end file number = 1
> 	c) data extraction completes successfully with 1201 rowsxcols
> 	d) d.erase; d.rast shows only single color for entire display
> am i missing some step? i even tried changing the color table with r.colors,
> and running r.support explicitly, but with no change.  i can display my
> Tiger data maps without any problems. any help would be appreciated.

Not that it is much help, but I am having the same problem.  It is strange,
the old version of the command in 4.0 worked fine.  The manual said that they
enhanced it, and that it was going to be pickier about headers.  It must be
very picky, because I imported 61 dem's and only 12 came in OK.

If you find a fix, could you summarize to the list or mail me a summary

Thank You,

Craig A. Miller
Pacific Northwest Geographics
Voice: (509) 662 4479
E-mail: cmiller at pnwg.wa.com

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