The Bay Area EcoAtlas is a computer-based Geographic Information System (GIS) of past and present local ecology in the San Francisco Bay Area, California. It was designed to support local and regional environmental planning and management. The EcoAtlas represents the integration of many kinds of information from numerous sources, to compile a picture of the environmental past, the present, and change. It provided the most detailed regional views of past and present ecological conditions that were available at the time of creation. It is also a spatial template to view possible scenarios for environmental management in the future, and a geographic index for spatially-related environmental data and their sources. The EcoAtlas was envisioned to be the "base map" for local and regional environmental planning and protection.