Click on outlined areas above or links below to access DEM and Bathymetry for the area. | A Digital Elevation Model (DEM) is a representation of the topography/ elevation of an area on a pixel-by-pixel basis in a raster-image format. The digital number at a given DEM pixel is equal to the elevation at that location (usually in feet or meters). The spatial information contained in a DEM can be used to complement the spatial and spectral information in remotely sensed satellite images. A nice aspect of working with DEM data is that they 'strip' away both man-made features and the effect of vegetation and soil types (it shows the surface strictly from a topographic/elevation point of view). On this webpage, we demonstrate some of the digital image processing and interactive analysis that can be done on the DEM data using the USGSMIPS, including enhancing and analyzing structural patterns and related topographic information. The DEM data shown on the pages linked below have a 30-meter horizontal and one-meter vertical spatial resolution and were used to generate color coded DEM and shaded relief images, as well as stereo pairs created by introducing parallax into the shaded relief images. These types of image products can be used to help map various landforms and structural features, such as surface fractures, faults, folds, and drainage patterns for the San Francisco Bay and Santa Clara areas. The original DEM data were acquired from the USGS National Mapping Division in individual 7.5 minute quadrangle format. Overall the data quality is good, however, there are several quads on the east side of the San Francisco Bay area data set that have relatively poor quality and will be noticeable when viewed at full resolution. |
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Project Team: |
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Pat S. Chavez, Jr. | Remote Sensing Scientist/ Team Leader |
JoAnn Bowell | Lead Image Processor on this project |
Miguel G. Velasco | Image Processor |
Stuart C. Sides | Computer Scientist |
Rosendo R. Gonzalez | Programmer |
Deborah L. Soltesz | Web Page Design |
For more information about this project, contact:
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Pat S. Chavez, Jr.
Email: pchavez@usgs.gov
U.S. Geological Survey 2255 N. Gemini Dr. Flagstaff, AZ 86001 Tel: (520) 556-7221 FAX: (520) 556-7169 |
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