2003. USGS National Center for EROS. The North America Shaded Relief data were derived from the GTOPO30 elevation data. GTOPO30 is a global digital elevation model (DEM) with a horizon... National Atlas of the United States.
Search Results
2003. National Geophysical and Solar-Terrestrial Data Center. This map shows light sources from human settlements around the world observed during 2003. The Defense Meteorological Satellite Program (DMSP) Oper... National Geophysical and Solar-Terrestrial Data Center.