Resolution: ~90 m, 3 arc-sec Coverage: Contiguous United States, Hawaii and parts of Alaska Projection: UTM Datum: WGS 72 Vertical Units: Meter
A Digital Elevation Model (DEM) consists of a sampled array of elevations for ground positions that are normally at regularly spaced intervals. The 1-Degree DEM (3- by 3-arc-second data spacing) provides coverage in 1- by 1-degree blocks for all of the contiguous United States, Hawaii, and limited portions of Alaska. The basic elevation model is produced by or for the Defense Mapping Agency (DMA), but is distributed by the USGS, EROS Data Center, in the DEM data record format. In reformatting the product the USGS does not change the basic elevation information. 1-degree DEM's are also referred to as "3-arc second" or "1:250,000 scale" DEM data.