DOQQ

http://www.crwr.utexas.edu/gis/gishydro00/Class/trmproj/Donnelly/termproject.htm

DOQQ stands for Digital Ortho Quarter Quads. They are a digital image of an aerial photo but also help to improve the terrain of the land being photographed. This is an example of a DOQQ map of Texas that shows a 500-year floodplain. These maps can be color schemed such as the Red above, or Black and White.