A work of geographic reference that supplies place name and location information. When a place name is known, a gazetteer can provide the coordinates of the place. Most atlases contain gazetteers. Well-known digital gazetteers are the USGS Geographic Names Information System (GNIS) and the gazetteer in the Digital Chart of the World (DCW). In ArcInfo the gazetteer spatial index is done as a grid of alpha and numeric references which is converted into a polygon coverage. Places (points or polygons) are then overlaid with this grid, then sorted alphabetically. This produces a list of place names sorted both alphabetically and by reference grid number.