                 ELEVATION DATA DISTRIBUTED BY USGS

The U.S. Geological Survey (USGS) produces and distributes elevation
products called Digital Elevation Models (DEM). Two types of DEM
products, called "1-Degree DEM" and "7.5 minute DEM", are available from
USGS.  The 1-Degree DEM has a resolution of 100 meters, while the 7.5
minute DEM has a resolution of 30 meters.

Although both the DMA and the USGS distribute DTED data, each distributes
it in a different tape format.  DTED data obtained from the DMA are
extracted using the GRASS program \m.dted.extract\.  DTED data obtained
from the USGS are extracted using the program \m.dmaUSGSread\.  Determine
the distribution source of your DTED data before you begin the tape
extraction process.

See:  \Characteristics of USGS 1-degree DEM Data\
      \Characteristics of USGS 7.5-minute DEM Data\
      \DEM Production Methods\
      \DEM Distribution\









