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description:
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This map contains the global ecological land unit (ELUs) data, produced from a partnership between USGS and Esri, to represent an ecophysiographic classification of the Earth’s surface based on the geographic coincidence of climate, landforms, geology, and land cover (Sayre and others, 2014). Combining the input data (bioclimate region, landform type, surficial lithology, and land cover) into a single 250-meter raster layer, called Ecological Facets (EFs), resulted in 106,959 unique combinations. These EFs represent the finest spatial resolution, globally comprehensive biophysical stratification yet attempted, and a detailed geospatial delineation of unique physical environments and their associated land cover. However although very rich in detail, the large number of EFs precluded meaningful cartographic display, therefore a separate generalized product termed Ecological Land Units was aggregated from the EFs by generalizing the number of input attribute classes down to 3,639 global ELUs. Additional information and access to this data is available at https://rmgsc.cr.usgs.gov/ecosystems/. |