Digital Orthophotography

Digital Orthophotos (DOQQs) combine the image characteristics of a photograph with the geometric qualities of a map. Unlike a standard aerial photograph, relief displacement in orthophotos has been removed so that ground features are displayed in their true ground position. This allows for the direct measurement of distance, areas, angles, and positions. Also, an orthophoto displays features that may be omitted or generalized on maps.

They serve a variety of purposes, from interim maps to field references for earth science investigations and analyses. The digital orthophoto is useful as a layer of a geographic information system and as a tool for revision of digital line graphs and topographic maps.

The State of Oklahoma currently has statewide digital orthophotos for the years 2003-2006. The 2003 orthophotos have a resolution of 1 meter while the 2004-2006 orthos are 2 meter. All images have been flown leaf on and are compressed using Mr. Sid into one file per county. The files can be downloaded from the Council’s ftp site: ftp://ftp.okcc.state.ok.us/gis/County.