Global Land One-km Base Elevation (GLOBE) 30-second DEM

The Global Land One-Kilometer Base Elevation (GLOBE) digital elevation model (DEM) is a global data set with horizontal grid spacing of 30 arc-seconds (0.008333... degrees) in latitude and longitude, resulting in dimensions of 21,600 rows and 43,200 columns. At the Equator, a degree of latitude is about 111 kilometers. GLOBE has 120 values per degree, giving GLOBE slightly better than 1 km gridding at the Equator, and progressively finer longitudinally toward the Poles.

The horizontal coordinate system is seconds of latitude and longitude referenced to World Geodetic System 84 (WGS84). The vertical units represent elevation in meters above Mean Sea Level. The elevation values range from -407 to 8,752 meters on land. In GLOBE Version 1.0, ocean areas have been masked as no data and have been assigned a value of -500. Due to the nature of the raster structure of the DEM, small islands in the ocean less than approximately 1 square kilometer (specifically, those that are not characterized by at least one 30 grid cell and/or do not have coastlines digitized into Digital Chart of the World or World Vector Shoreline) may not be represented.

Six gridded DEMs, and five cartographic sources, were adapted for use in GLOBE. Sources include: National Imagery and Mapping Agency, Digital Terrain Elevation Data Level 1 and 0; Australian Surveying and Land Information Group (AUSLIG) and the National Geophysical Data Center (NGDC), 30 DEM for Australia; Geographical Survey Institute (GSI), 30 DEM for Japan; Servizio Geologico Nazionale (SGN) and NGDC, 30 DEM for Italy; Manaaki Whenua Landcare Research, Ltd. (LCR),DEM for New Zealand; NASA/Goddard Space Flight Center, DEM for Greenland from GEOSAT Altimetry; Defense Mapping Agency (now National Imagery and Mapping Agency),Digital Chart of the World; Army Map Service (now National Imagery and Mapping Agency), Maps for South America, South Pacific, and East Indies; Instituto Brasiliero de Geografia e Estatistica, Maps for the International Map of the World on the Millionth Scale; Ministerio de Guerra, Peru, Mapa Fisico Politico del Peru; and Scientific Committee for Antarctic Research, Antarctic Digital Database. A total of 18 combinations of source/lineage were used in GLOBE.