GeMS (“Geologic Map Schema,” formerly “NCGMP09”) is the standard schema for geologic map publications funded by the U.S. Geological Survey’s National Cooperative Geologic Mapping Program (NCGMP). GeMS defines the capture, in a digital format, of the content contained on geologic maps. The databases are set up for Map Unit Polygons, contacts and faults, orientation data, overlay polygons, and all other geological lines and symbols, along with all the written information, such as descriptions of map units, source data, and other metadata.