DOQQ

    

     http://www.geology.enr.state.nc.us/doqq.html

     A Digital Orthophoto Quarter-Quadrangle (DOQQ) is an image that has been geometrically corrected so that the distance between two point is the true distance. They are recognized as one of several critical geo-spatial data sets needed to effectively manage and use geographic information systems in statewide, regional and local databases and spatial applications. This example shown about is part of the Farmville NE DOQQ. Maps of this type are often put into a GIS and are used to make vector data files.