A map having background information, such as state, county, or city boundaries, upon which more detailed data is plotted.
A map which depicts fundamental information about the Earth's surface, such as landforms, drainage, landmark features and political boundaries. Many features are identified by geographical names or labels. Base maps usually come in a series and are used as a locational reference base for thematic information. Smaller scale regional reference maps are often derived from these bases. Topographic and planimetric maps are examples of base maps.
A map showing certain fundamental information, on which is compiled additional data of specialized nature. Also a map to which all other maps and GIS map layers are registered and re-scaled.