The Presence Grids of the Gridded Global Amphibian Species Distribution is a reclassified version of the original grids of amphibian species distribution maps. The data include 1- kilometer presence/absence grids for individual species available in Geographic Coordinate System (GCS). The input vector layers were produced by a consortium led by NatureServe. The gridding and grid processing are done by the Columbia University Center for International Earth Science Information Network (CIESIN).

http://sedac.ciesin.columbia.edu/gateway/guides/species_amppres.html