-
Federal
USGS Digital Orthophoto Quadrangles
National Aeronautics and Space Administration —
A Digital Orthophoto Quadrangle (DOQ) is a computer-generated image of an aerial photograph in which the image displacement caused by terrain relief and camera tilt... -
Federal
Global Land Cover Characterization Program
National Aeronautics and Space Administration —
The Global Land Cover Characterization Project was established to meet science data requirements identified by the International Geosphere and Biosphere Programme...