Global Data Archive 3:  1 Km Global Elevation Model

The Global Data Archive 3: 1 Km Global Elevation Model contains the GTOPO30 global coverage digital elevation model (DEM)converted to IDRISI format at 30-arc second resolution. The archive size is 280 MB. Download size is 274 MB.

The GTOPO30 data files were downloaded from the USGS EROS data center DAAC-GTOPO web page at http://edcdaac.usgs.gov/gtopo30/gtopo30.html.

The original tile division (33 pieces), projection (geographic, reference units: decimal degrees of latitude and longitude), data definition (elevation value in meters, -9999 represents ocean areas), and spatial resolution (30-arc seconds, approximately 1 km) are maintained in the converted files.

Images covering 60 degrees south latitude to 90 degrees north latitude and 180 degrees west longitude to 180 degrees east longitude (27 tiles total) have 4800 columns and 6000 rows each (covering 50 degrees of latitude and 40 degrees of longitude per image); and those covering the Antarctic area (90 degrees south latitude to 60 degrees south latitude and 180 degrees west longitude to 180 degrees east longitude, total 6 tiles) have 7200 columns and 3600 rows each (covering 30 degrees of latitude and 60 degrees of longitude per image).

These images are stored in integer format.

Detailed information about the GTOPO30 data can be found in the GTOPO30 documentation file at http://edcdaac.usgs.gov/gtopo30/README.html.