Digital Orthophoto Quadrangle (DOQ) |
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A Digital Orthophoto Quadrangle (DOQ) is a digital, uniform-scale image created from aerial photos. It is a photographic map in which ground features are displayed in their true ground position because relief displacements caused by the camera and terrain of an aerial photograph have been removed. It combines the image characteristics of a photograph with the geometric qualities of a map; thus, it is possible to get direct measurements of distances, areas, angles, and positions from a DOQ. What is the difference between an aerial photograph and an orthophoto?
For more information about DOQs, please visit DOQ DownloadA standard DOQ is distributed in a quarter section of a standard 7.5-minute quadrangles. The one meter resolution of the DOQ results in a very large file size. Each quarter quadrangle DOQ is ~50MB; the complete mosaicked DOQ for the Lake Tahoe Basin is ~3GB. DOQs are often compressed with JPEG compression, but for distribution
here, all the DOQs for the Lake Tahoe Basin have been mosaicked together
and compressed with MrSID compression from
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U.S. Department of the Interior
|| U.S. Geological Survey
|| National Mapping Information
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