Global topography and bathymetry grid improves research efforts



Gridded data of topography and bathymetry of the Earth's surface have become widely available via the Internet, thanks to the efforts of multiple research groups, including, for example, the U.S. Geological Survey (, Smith and Sandwell [1997], and Jakobsson et al. [2000]. These data are of continually growing importance both for monitoring operations and for scientific research, as they are critical for the clear presentation of final results to end-users.

Nevertheless, in general, for a given region of the world, there is a final step in assembling all the necessary sub-regions into a continuous grid that represents the area of interest. Also, one must account for the varying resolutions of the component data sets. These issues are surmountable, though painstaking.Three publicly available gridded data sets of topography and bathymetry have been combined to produce a single, integrated data set with no loss in resolution.The 3 data sets are the GTOPO30 data from the U.S. Geological Survey the Global Bathymetry data set from Smith and Sandwell [1997],and version 1.0 of the International Bathymetric Chart of the Arctic Ocean (IBCAO) data set [Jakobsson et al., 2000]. Results are provided as eight GMT grid files covering −180° to +180° longitude and −90° to 90° latitude. To facilitate ease of use without loss of resolution, all data have been sampled and merged into identically registered 30-s grids. The actual resolutions of the topography and bathymetry data are roughly 30 arc s (0.66 km at 45° latitude) and 2 arc min (2.6 km at 45° latitude), respectively Results are made available free of charge via internet through the Geographic Information Network of Alaska (GINA). The Web address for this server is