m.dem.extract

[Keith Mitchell]

Sparc 2
SunOS 4.1.3
Grass4.1 rev 3

We are trying to bring in some USGS 7.5 minute dem data from
tape.

The original tapes were read elsewhere and ftped to
our site because we do not have the necessary tape
drive.

this command was used to extract them from the tape:

dd if=/dev/rmt21 of=file1 cbs=1024 ibs=31744 conv=unblock

	when I try to run the extract program, 

m.dem.extract input=file1 output=lala blocksize=1024

 I get warnings about unexpected c records.  This map 
has the proper bit set to indicate there is a c record, 
but I think there should only be one c record for the entire file.  

Furthermore, as the program continues onto other "Files" in
the same file, the resolution values returned become ridiculous.

Using the USGS attachment sent with the maps, I cannot reconcile
the byte positions for each piece of information.

(I used the command od -c file1)


It seems like the info got garbled somewhere along the line.
Where did we go wrong?


Keith M. Mitchell
University of Illinois
Department of Ag. Engineering
Urbana, IL 61801