Digital Orthophoto Quadrangle

A Digital Orthophoto Quadrangle (DOQ) is a digital, uniform-scale image created from aerial photos. It is a photographic map where ground features are displayed in their true ground position, because relief displacements caused by the camera and the terrain 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.

A DOQ may be used as a source or background layer in a geographic information system (GIS) to collect, review, and revise other digital data. A DOQ can be combined with a DEM and a DRG to produce an image with additional visual information for the extraction and revision of base cartographic information.

To learn more about DOQs, check out the DOQ 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:

doq_1993_tif.zip (181 MB uncompressed) -- DOQ with world file in TIFF format.

doq_1993_sid.zip (37 MB uncompressed) -- DOQ with world file in Mr. SID format

doq_1948.zip (102 MB uncompressed) -- Historical DOQ with world file in Mr. SID format.

Metadata

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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/doq.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