EarthWorks [via Stanford University]

Data can be searched spatially, by manipulating a map; by keyword search; by selecting search limiting facets (e.g., limit to a given format type); or by combining these options. Data are available from numerous research institutions across the United States covering a vast array of subjects and base layer information. Thousands of datasets in vector and raster format have been described at the individual layer level allowing for easy searching and retrieval. Both public and restricted data, with restricted data tied to the institution that holds the content.