DOQs produced by the U.S. Geological Survey (USGS) are either gray-scale, natural color, or color-infrared (CIR) images with 1-meter ground resolution. They cover an area measuring 3.75-minutes longitude by 3.75-minutes latitude or 7.
About DOQs
The standard quarter-quadrangle image covers 3.75 minutes of latitude by 3.75 minute of longitude, at a scale of 1:12,000 cast on the Universal Transverse Mercator projection based on the North American Datum of 1983.
They know, for example, the conventions that allow the producers of DOQs to assert that the representative fraction of their product is 1:12,000 (Goodchild and Proctor 1997).
These images have been resampled to fit accurately onto a ground coordinate grid with very high pixel resolution--usually 1 or 2 m; they may be used with a GIS in combination with other kinds of cartographic data. DOQs are now being tested and ...
The technique is mainly aimed at using free DOQQ data for those states that offer them. However, these techniques work just as well for DOQs.
 See also: Mapping, Cover, GIS, Information, Map
  
|
RSS
