problem with USGS DEM's

[Cleavy GRASS mail]

Subject: problem with USGS DEM's

SOME of these USGS 1 degree x 1 degree DEM's have differing "C-numbers"
somewhere in their headers.  SOME are read without any problem using
m.dem.extract

OTHERS, however, I have NEVER successfully read, either using m.dem.extract
OR m.dmaUSGS.read, etc.

Anybody have a solution to this COMMON problem?

---Cleavy McKnight
   Dept. of Geology
   Baylor University
   Waco, TX 76798-7354
   cleavy2 at earthlogic.baylor.edu

Date: Mon, 10 Jan 94 16:19:43 CST
From: wang at cast.uark.edu (Wang Song)
Subject: Re: USGS dems into grass

	Have you tryed to use command "m.dem.extract" to extract your DEMS ?

	The command don't have to read from a tape drive, it could read from a
disk file. Usually, you could try blocksize of 4096 or 10240 when the GRASS
command ask for it. Your DEMS are 7.5 minute USGS DEMs, right ?

Song Wang
CAST/NCRI


> I have one of the ever-popular USGS dems here.  It came from the Reston ftp site, and I want to bring it into Grass.  I am specifically interested in hearing from someone who has already done this SUCCESSFULLY.  I know that there must be someone out there who has.  
> 
> My attempts so far have been to use the commands m.dmaUSGSread and m.rot90 and r.in.ll.  These have lead to unreadable, smeared DEMs.  I have only been able to view the DEM after some row-col calculations, a new header, and the use of r.in.ascii.  However, the file still needs to be rotated 90 degrees counter-clockwise.  So I'm still stuck.
> 
> Please lend a hand and I'll summarize the info I get.
> 
> Thanks.  I'll give out any additional info I can if it's needed.
> 
> -Eric