webgis page says
USGS 1-Degree Native Format - United States
Resolution: ~90 m, 3 arc-sec
Coverage: Contiguous United States, Hawaii and parts of Alaska
Projection: UTM
Datum: WGS 72
Vertical Units: Meter
AND HOW exactly does it explain the file data at 30 30 1
Vs
3 3 1, not seen there, but in gce.dem, included.
