Mapping Techniques for the San Francisco Bay Region , California

Demographic data are commonly represented by using a choropleth map, which aggregates the data to arbitrary areal units, causing inaccuracies associated with spatial analysis and distribution. In contrast, dasymetric mapping takes quantitative areal data and attempts to show the underlying statistical surface by breaking up the areal units into zones of relative homogeneity. This thesis applies the dasymetric mapping method to the 1990 U.S. Census blockgroup populations of Alameda County, California using the U.S. Geological Survey’s 1992 National Land Cover Data Set and other ancillary land-cover sources to redistribute the block-group populations into a 30-m grid based on categorical zones relative to population distribution. To test the accuracy of the dasymetric approach, census block populations were compared with the dasymetric mapping distributions; the results yield high correlation coefficients (between 0.80-0.88), indicating that the dasymetric mapping method produced more...