Global Multi-Resolution Topography Data Portal
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The Global Multi-Resolution Topography (GMRT) synthesis [current version: 2.4] is a compilation of multibeam sonar data collected by scientists and institutions worldwide, edited and merged into a single continuously updated compilation of high-resolution seafloor topography. The synthesis began in 1992 as the Ridge Multibeam Synthesis (RMBS), and now includes other bathymetry from throughout the global and coastal oceans.
As of June 2011: GMRT is part of the ocean map in GoogleEarth!
GMRT is maintained as a multi-resolution gridded digital elevation model that includes seafloor bathymetry to ~100 m spatial resolution (to ~50 m in some coastal regions). NOAA coastal grids and numerous grids contributed by the international science community are also integrated into the GMRT Synthesis. Multibeam data are merged with lower-resolution compilations including the General Bathymetric Chart of the Oceans (GEBCO 08), the International Bathymetric Chart of the Arctic Ocean (IBCAO), and the SCAR Subglacial Topographic Model of the Antarctic (BEDMAP). Also included are elevation data from NASA’s Advanced Spaceborne Thermal Emission and Reflection Radiometer global DEM (ASTER) which provide 30 m resolution of terrestrial areas throughout the world, and the USGS National Elevation Dataset (NED) providing up to 10 m resolution in some areas of the US.
Additional information about the tiling method and procedures used for creating and serving the Global Multi-Resolution Topography (GMRT) synthesis is available in Ryan et al., 2009. The data DOI for GMRT is 10.1594/IEDA.0001000. View the list of contributors whose data have been incorporated into GMRT.