Digital Elevation Model

A Digital Elevation Model (DEM) is digital cartographic/geographic data in raster form. The terrain elevations for ground positions are sampled at regularly spaced horizontal intervals. DEMs are derived from hypsographic data (contour lines) and/or photogrammetric methods using USGS 7.5-minute, 15-minute, 2-arc-second (30- by 60-minute), and 1-degree (1:250,000-scale) topographic quadrangle maps.

The 7.5- and 15-minute DEMs are within the large-scale category, the 2-arc-second DEMs are within the intermediate-scale category, and the 1-degree DEMs are within the small-scale category.

To learn more about DEMs, check out the DEM page at the Crater Lake Data Clearinghouse Web site.

Data Download

The San Francisquito Creek project covers six USGS 7.5-minute quadrangles. These six quads have been mosaicked together for your convenience of viewing and analyzing the information throughout the area. Data are reprojected to one standard projection (UTM NAD27 zone 10 meters). Click on the following link to download the data:

dem.zip (1.6 MB uncompressed) -- DEM with world file in JPEG format.

Metadata

Single quadrangle, USGS 10-meter DEM at 1:24,000 scale is available for download at the San Francisco Bay Area Regional Database (BARD) Web site.

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Introduction Study Area

Framework GIS Project

Digital Data Issues

Contacts Links

U.S. Department of the Interior || U.S. Geological Survey || National Mapping Information || Western Regional Geography URL: http://geography.wr.usgs.gov/sfcreek/dem.html Designer and Maintainer: Connie Hoong, choong@usgs.gov Webmaster: Gary Sullivan, gsullivan@usgs.gov Last Modified: Friday, 07-Feb-2003 22:42:49 EST (cmh) Privacy Statement || Disclaimer || FOIA || Accessibility || Search