Global 30 sec Arc-Second Hydro-logic One Kilometer Elevation

The HYDRO1k data sets are the result of the cooperative project at the U.S. Geological Survey's (U.S.G.S.) EROS Center. The goal of the project is the development of a globally consistent hydrologic derivative data set. The effort has been led by U.S.G.S. scientists in collaboration with the United Nations Environment Programme/Global Resource Information Database (UNEP/GRID) located in Sioux Falls, South Dakota.

Development of the HYDRO1k database was made possible by the completion of the 30 arc-second digital elevation model at EROS in 1996, entitled GTOPO30. This data set, with its nominal cell size of 1 km, has been and will continue to be applied by many scientists and researchers to hydrologic and land form studies. Inevitably, these studies require development, at a minimum, of a standard suite of derivative products.
The HYDRO1k package provides, for each continent, a suite of six raster and two vector data sets. These data sets cover many of the common derivative products used in hydrologic analysis. The raster data sets are the hydrologically correct DEM, derived flow directions, flow accumulations, slope, aspect, and a compound topographic (wetness) index. The derived streamlines and basins are distributed as vector data sets.