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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.
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:
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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