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@earthlogic.baylor.edu
Date: Mon, 10 Jan 94 16:19:43 CST
From: wang@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