# GRASS Help System

## 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

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Automatically created on: Wed Oct 12 14:08:40 2005