Source: American Community Survey, 2011 5-Year Estimate
This map was inspired by a similar map found on Wikipedia. I wasn’t wild about the diverging color scale, so I thought it would be a fun challenge to recreate.
Finding the shapefiles was easy; I used the U.S. National Atlas 1:1,000,000 scale dataset, conveniently packaged in my U.S. Atlas repository. I reprojected the shapefiles to the California Albers projection using ogr2ogr:
ogr2ogr \
-f 'ESRI Shapefile' \
-t_srs 'EPSG:3310' \