Here are more complete directions to import DMA data
I suspect you geographic region and resoulutions weren't set
up correctly:
ftp site: resdgs1.er.usgs.gov
1) dd if=diskfilename ibs=10240 | \
m.dmaUSGSread top=1 bottom=400 left=1 right=500 \
output=dem logfile=log
Of course you need to substitute the right parms for your area. (I left
the blocking parm as above.)
2) m.rot90 input=dem output=dem.r90
rows=400 cols=500 bpc=2
3) Create a region (in UTM coordinates) with g.region, then
use m.ll2u to convert nothings and eastings of them map
to utm. (first divide them by 3600, adjust ew_res and ns_res
so that there are 1200 rows and 1200 cols.
r.in.ll input=dem.r90 output=dem.utm
dimension=500,400 bpc=2 res=3,3
corner=sw,37:13N,103:45W spheroid=wgs72
in the command above you have to give lat-long for a corner of your
dem using the wgs72 spheroid. The r.in.ll command should create all
the necessary support files for you. But if you run into problems,
just run r.support.