A cartogram is a thematic map that is "drawn so that the areas of internal enumeration units are proportional to the data they represent".1
This cartogram series uses the county as the enumeration unit, and resizes them relative to other counties to show population patterns across the state of California. At a glance it should be clear that population is not evenly distributed across the state. Perhaps more striking is the temporal dimension to California's population growth. Select from six years, spaced 20 years apart, to view the state's growth over the twentieth century. A discussion to accompany each selection will appear at the top of this column. The sizing of the county polygons remains consistent across throughout the visualization, for example allowing the magnitude of San Francisco's population in 1900 to be compared to the Sacramento's 1980 population.
This is a semi-contiguous cartogram. Due to the fact that some counties with large land areas have very small populations, some small counties have large populations, and a wide range in between, some shearing is inevitable as the counties are resized according to population.
Population data was acquired from the US Census Bureau.7 Check out the readme on GitHub to learn more about how the cartogram artwork was created.
This work marks the ten-year anniversary of one of my earliest grad-school projects, reimagining and redesigning it along the way. See the original work in the readme above.
Works cited and further reading
Dent, Borden D. (1996). Cartography: Thematic Map Design. p. 203. 4th Ed. Dubuque, Iowa: Wm. C. Brown Publishers.
California Legislative Analyst's Office. (2000). "2000 Cal Facts. California's Economy Part 1". link. Accessed 16 March 2018.
Walker, Richard A. (2007). The Country in the City: The Greening of the San Francisco Bay Area. Seattle, Washington: University of Washington Press.
Johnson, Hans. (2017). "California's Population". Public Policy Institute of California. link. Accessed 16 March 2018.
Johnson, Marilynn S. (1993). The Second Gold Rush: Oakland and the East Bay in World War II. Berkeley, California: University of California Press.
Olmstead, Alan L. and Paul W. Rhode. "A History of California Agriculture". Giannini Foundation Information Series 017-1, University of California Agriculture and Natural Resources. link. Accessed 16 March 2018.
Forstall, Richard L., Population Division, US Bureau of the Census. (1995). "California: Population of Counties by Decennial Census: 1900 to 1990". link. Accessed 16 March 2018.