Digital Elevation Models (DEMs)
Digital elevation model (DEM) data are arrays of regularly spaced elevation values referenced horizontally either to a Universal Transverse Mercator (UTM) projection or to a geographic coordinate system. The grid cells are spaced at regular intervals along south to north profiles that are ordered from west to east. The U.S. Geological Survey (USGS) produces five primary types of elevation data: 7.5-minute DEM, 30-minute DEM, 1-degree DEM, 7.5-minute Alaska DEM, and 15-minute Alaska DEM.
These 10 meter, 7.5' DEMs are the latest from USGS.
We do not have quad specific metadata for these files but to learn more about DEMs go to the USGS DEM page
Datum: NAD27 or NAD83
These 30 meter, 7.5' DEMs are ArcInfo grid files that have been exported.