Surface of the Earth, 2 minute bathymetry/topography image selection
45 degrees by 45 degrees, Cylindrical Equidistant Projection

This image was generated from digital data bases of seafloor and land elevations on a 2-minute latitude/longitude grid (1 minute of latitude = 1 nautical mile, or 1.853 km). Assumed illumination is from the west; shading is computed as a function of the east-west slope of the surface with a nonlinear exaggeration favoring low-relief areas. A Cylindrical Equidistant projection was used for the world image, which spans 360 degrees of of longitude from 180 West eastward to 180 East; latitude coverage is from 90 degrees North to 90 degrees South. The resolution of the gridded data varies from true 2-minute for the Atlantic, Pacific, and Indian Ocean floors and all land masses to 5 minutes for the Arctic Ocean floor. Major data sources are as follows: for Ocean Areas between 72 degrees North to 72 South latitude, bathymetry is derived from satellite altimetry of the sea surface; poleward of 72 degrees, data are from the U.S. Naval Oceanographic Office. Land Topography is primarily from various sources collected and gridded at 30 minute resolution by the National Imagery and Mapping Agency, US Department of Defense.