This polygon shapefile California represents the California county boundaries at moderate spatial resolution, aligned to match well with the ARB California Air Basins and California Air Districts polygon boundary shapefiles. This shapefile is aligned to match well with the ARB California Air Basins and California Air Districts polygon boundary shapefiles. It is not intended to replace more spatially detailed county boundary layers available elsewhere. Teale Data Center GIS Lab. California Air Resources Board. (2004) California Counties: Air Resources Board, 2004. California Air Resources Board. Available at: http://purl.stanford.edu/qy535rr9441. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.