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GTOPO30: Global 30 Arc-Second Elevation
GTOPO30 is a global digital elevation model (DEM) with a horizontal grid spacing of 30 arc seconds (approximately 1 kilometer). The DEM was derived from several raster and vector sources of topographic information. Completed in late 1996, GTOPO30 was developed over a three-year period through ... gtopo30 elevation topography dem geophysical nasa
