This is FREE software and FREE data that gives incredible power to the geologist who can't afford expensive GIS software. The USGS provides free Digital Elevation Models for virtually every 7.5' topographic quadrangle in the United States. With these two software programs one can analyze and manipulate the data in the models in incredible ways.
Download DEM Data
Scroll down to "FTP by state." Select your state and then quadrangle. For detailed instructions on how to download go to Professor Steve Reynolds' site at Arizona State University. Warning: If you use Netscape, follow the instructions carefully about the "tar.gz."
Download DLG Data
Digital Line Graph (DLG) is a vector file containing line data, such as roads or streams, digitized from quadrangle maps based on planimetric base categories such as transportation, hydrography, and boundaries.
Download Software to View DEM
This site at the Naval Academy provides a slick program (MicroDem) to view the DEM data. This program gives perspective views, slope maps, contour maps, trend-surface residuals, and much, much more. You can even figure out how to set up your artillery battery.
SDTS Conversion
The SDTS data format is new. Many commercial programs can not yet import it directly. Programs such as ERMapper, Surfer and others need to have the data converted back to the old format in order to be imported. This BLM site contains several conversion programs.
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