crayola nation : paint by votes !

A map is a popular graphic device to communicate election results. Usually choropleth maps are used to portray voting behavior. The problem with choropleth (or value-by-area) maps to depict information related to people is that they visually emphasize the land (e.g., an enumeration unit such as a state), and not the people living on the land (i.e., the voters).

A typical election map example is the map on the left from CBS' Web site which was made by ESRI the 'GIS software leader', but hopefully not by a cartographer. The fact that ESRI headquarters are located in REDlands (CA) can only be a coincidence... ?

This choropleth map stands for all the similar ones that were shown on TV stations during election night, Tuesday, Nov. 2 2004. Unfortunately, mapping totals or absolute values per enumeration unit (e.g., electoral or individual votes by state) is unacceptable by sound cartographic standards, if the goal is to show thematically relevant information in a perceptually salient manner.

The enumeration units (e.g. states) are unequal in area, thus might give the reader a false impression of the mapped data distribution.  A person not familiar with the U.S. voting system might wrongly assume that President. George W. Bush is winning the election hands down, considering that two thirds of the U.S. is shaded in red. However, the race is much closer. Bush did win 28 of the 51 states (at the time of writing), but only 254 of the electoral votes (58,601,943 votes, or 51,08% of the popular vote). Senator John Kerry on the other hand scored only in 20 states, but still received 252 of the crucial electoral votes (55,071,989, or 48% of the popular vote, election data from the New York Times).

populated areas in the U.S. (© by sara i fabrikant)

The two-variable contiguous area cartograms below also depicts enumeration units proportionally scaled to the data that they represent (e.g., electoral votes). The more electoral votes in a state, the larger the state. In addition, traditional choropleth shading is applied, showing the proportion of people voting for a candidate.

Input data for a cartogram is never classified. The cartogram is therefore one of the truest form of quantitative mapping. This is why a cartogram legend should include a continuous tone color bar, showing a continuous data range from minimum to maximum value (not labeled).

The vast Rockies, the rural Plains and the deep South are RED-land in crayola nation. The 'BLUES' have settled in the highly urbanized, populous states, at the 'edges' of Red/Blue America.

Due to popular demand, finally a cartogram on county level data. The counties are scaled by population (2000). The shading is the percentage of the popular vote for President Bush. The overall pattern (e.g., shape distortion of the U.S.) is similar as in the state-level cartogram. However, data at a finer spatial scale allows to see a more nuanced picture of the election results. Populous counties containing large cities (e.g., New York, Chicago, Los Angeles, San Francisco, etc.) are typically blue, even though they may lie deep in red state land (e.g.., St. Louis, Denver, Minneapolis, Miami, Palm Beach, etc.).

most likely to be found among highly educated women, non-churchgoers, union members and the “cosmopolitans” of the New York area, New England and California.

older, more likely to be married, less likely to join a union, more likely to be regular churchgoers—mostly at Protestant churches—far more likely to be “born again” Christians...

Another problem with the ubiquitous blue/red choropleth map is that only one piece of information is shown, namely, who won which state.
Inspired by statistician Hermann Chernoff's faces the map on the left depicts four variables at once: 1) the continuously scaled face* represents the number of electorate votes per state (the larger the face the more votes), 2) the continuously morphed face between Sen. Kerry and President Bush depicts the percent of popular vote for President Bush. The fewer votes for Bush, the more the face resembles Sen. Kerry, 3) the choropleth shading indicates the percentage of urban population in each state, and finally 4) relief shading gives a sense of the physical terrain across the nation. Click on the map to see a larger version image (here for a higher resolution PDF, ~ 4MB).
See here for an example of the 1996 presidential election by Keith Clarke.

*the resemblance of the about 55% digitally morphed face between Kerry and Bush (e.g., face in California) with this man is striking!