The Mapping and GIS Division maintains the County's Geographic Information System (GIS), generates map products, and provides spatial analysis services for the County, other agencies and the public. The GIS is a computer-based repository of digital maps, databases and software that provide for the capture, organization and display of spatially distributed data. The Division maintains a wide variety of maps and is continually gathering maps from a variety of sources.

Examples of map resources include Assessor parcels, digital orthophotographs, elevation contours, administrative districts, policy boundaries (e.g., General Plan, zoning), Countywide Plan reference maps, voting precincts, census boundaries and natural features. The Mapping and GIS Division is in the process of bringing GIS capability to the desktop of County departments and to the public via the World Wide Web.