Tue Mar 14 07:15:44 1989 elevation PERMANENT grass cell 7.5 minute Digital Elevation Model (DEM) produced by the USGS Elevation above mean sea level in meters for spearfish database DEM was distributed on 1/2 inch tape and was extracted using GRASS DEM tape reading utilities. Data was originally in feet and was converted to meters using the GRASS map calculator (Gmapcalc). Data was originally supplied for both the Spearfish and Deadwood North USGS 1:24000 scale map series quadrangles and was patched together using GRASS