Historic Vegetation Base Map (Pre-1900), Central Valley Historic Mapping Project

SUMMARY Development of the map set and GIS consisted of researching libraries for archival information, developing GIS tools for data input, and displaying and analyzing information from a variety of agency and academic sources. Over seven hundred maps were scanned and will ultimately be made available on a library site for viewing and/or downloading. The Pre-1900 Base Map was the most difficult to construct due to the limited information recorded at that time. Vegetation polygons were developed from several independent map sources. The quality of information on the source maps varies by area and by source. Map series were more readily available for the 1945, 1960 and 1990 time periods. The maps are GIS-based and can be used to estimate vegetation change over time. In all cases attempts were made to gather the best information available and to create a bank of accessible information that can be utilized in future research efforts. We see this project as a good base for continued additions and refinements rather than as an end product. We would like to invite other interested federal and state agencies to participate in the project.