Maps and cartograms of the 2004 US presidential election results (Compendium of Election Result Maps

Department of Physics and Center for the Study of Complex Systems, University of Michigan ^ | November 12, 2004 | Michael Gastner, Cosma Shalizi, and Mark Newman

[JerseyHighlander]

Maps and cartograms of the 2004 US presidential election results

Michael Gastner, Cosma Shalizi, and Mark Newman
University of Michigan

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Email: Thanks to everyone who wrote to us about the maps. We received so much email that we may not be able to reply to everyone, but we much appreciate all your comments and suggestions.

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Election results by state

On election night and in the days since then, we have seen many maps that look like this (click on any of the maps for a larger picture):

The (contiguous 48) states of the country are colored red or blue to indicate whether a majority of their voters voted for the Republican candidate (George W. Bush) or the Democratic candidate (John F. Kerry) respectively. The map gives the superficial impression that the "red states" dominate the country, since they cover far more area than the blue ones. However, as pointed out by many others, this is misleading because it fails to take into account the fact that most of the red states have small populations, whereas most of the blue states have large ones. The blue may be small in area, but they are large in terms of numbers of people, which is what matters in an election.

We can correct for this by making use of a cartogram, a map in which the sizes of states have been rescaled according to their population. That is, states are drawn with a size proportional not to their sheer topographic acreage -- which has little to do with politics -- but to the number of their inhabitants, states with more people appearing larger than states with fewer, regardless of their actual area on the ground. Thus, on such a map, the state of Rhode Island, with its 1.1 million inhabitants, would appear about twice the size of Wyoming, which has half a million, even though Wyoming has 60 times the acreage of Rhode Island.

Here are the 2004 presidential election results on a population cartogram of this type:

The cartogram was made using the diffusion method of Gastner and Newman. Population data were taken from the 2000 US Census. Iowa and New Mexico, which at the time of writing were officially undeclared, we have assumed to have a Republican majority -- all indications are that this will be the final declaration once recounts are complete.

The cartogram reveals what we know already from the news: that the country was actually very evenly divided by the vote, rather than being dominated by one side or the other.

Election results by county

But we can go further. We can do the same thing also with the county-level election results and the images are even more striking. Here is a map of US counties, again colored red and blue to indicate Republican and Democratic majorities respectively:

Similar maps have appeared in the press, for example in USA Today, and have been cited as evidence that the Republican party has wide support. Again, however, a cartogram gives a more accurate picture. Here is what the cartogram looks like for the county-level election returns:

Again, the blue areas are much magnified, and areas of blue and red are now nearly equal. However, there is in fact still more red than blue on this map, even after allowing for population sizes. Of course, we know that nationwide the percentages of voters voting for either candidate were almost identical, so what is going on here?

The answer seems to be that the amount of red on the map is skewed because there are a lot of counties in which only a slim majority voted Republican. One possible way to allow for this, suggested by Robert Vanderbei at Princeton University, is to use not just two colors on the map, red and blue, but instead to use red, blue, and shades of purple to indicate percentages of voters. Here is what the normal map looks like if you do this:

And here's what the cartogram looks like:

In this map, it appears that only a rather small area is taken up by true red counties, the rest being mostly shades of purple with patches of blue in the urban areas.

A slight variation on the same idea is to use a nonlinear color scale like this:

These maps use a color scale that ranges from red for 70% Republican or more, to blue for 70% Democrat or more. This is sort of practical, since there aren't many counties outside that range anyway, but to some extent it also obscures the true balance of red and blue.

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Notes:

Outage: This page was unreachable for several hours on Sunday November 7 because of an electrical fault on the University of Michigan campus. Everything appears to be running smoothly again now. Apologies for the inconvenience.

Correction: The figures for numbers of counties voting Rep/Dem were off because of a bug in one of our programs. We've fixed this and corrected the text above. Thanks to K. Drum and others for pointing this out. (All the actual maps were fine however.)

Update: We've done some slight improvements to the cartograms, based on updated population and electoral data. (You'll have to look pretty hard to see any difference though.)

Update: We changed the color scale on the purple maps to be the same as that used by Robert Vanderbei. The old maps are still available above for those who are interested.

Wallpapers: By popular demand, all of the maps are now available in "wallpaper" sizes for your computer desktop. Click here.

Correction: The colors of a few counties in Texas and in Delaware got swapped around because of differences in the alphabetizing of lists of election returns. This is fixed now on all the maps. Thanks to J. Henderson and S. Hughes for spotting the problems and letting us know.

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© 2004 M. T. Gastner, C. R. Shalizi, and M. E. J. Newman

This work is licensed under a Creative Commons License. Text and images may be freely distributed. We would appreciate hearing from you if you wish to make use of our work.

High-resolution versions of the figures are available here. Even higher-resolution ones are available on request from the authors.

Our computer software to produce cartograms is freely available here.

The views expressed are personal and are not necessarily shared by the University of Michigan.

Mark Newman, Department of Physics and Center for the Study of Complex Systems, University of Michigan
Updated: November 12, 2004

[JerseyHighlander]

For all of your Election 2004 needs. Hopefully this can cut down the vanity posts asking for election result maps.

[JerseyHighlander]

I can't believe I spelled compendium wrong. Could I get a clean up on aisle 1279328?

[PhotoFixer3]

dahhhh.....

[Reeses]

Population data were taken from the 2000 US Census.

Why use 2000 data for population distribution numbers? The 2004 election's high turn-out is in effect a more accurate census.

[GSlob]

Isn't premeditated topological distortion of the nation's map a punishable offense, akin to mutilation of a passport?

[RockinRight]

Interesting.

What this fails to point out is that the "real" America voted for Bush. The elitists and "Europeized" America voted for Kerry.

[MisterRepublican]

The cartograms resemble the liberal view of reality, distorted.

[Rastus]

I prefer this to the cartograms:

[Paladin2]

W0W, Long Island gets REALLY fat based on population. Maybe it should be its own state.

[Admin Moderator]

Good post, but please remember to use the published heading. Thanks.

[Dan from Michigan]

Should have made the cutoff 60%, not 70%.

There's no way Wayne(69.5%, but they gave it blue), Livingston(Red), Allegan(red), Washtenaw(Blue), or Genesee(blue) counties are "purple"

[AM2000]

Interesting.

This map lays to rest the myth that the Republican party's base is in the old South.

It would be more accurate to say that the 'base' lies in the middle section - from Texas to about Nebraska, in addition to parts of the Rocky Mountain states.

[Wonder Warthog]

You left out the BEST representation---the "3-D" map by county. It makes the necessary census-related points FAR BETTER than the cartogram distortions.

[M-cubed]

Now that the election is over and "We the people" have spoken.....Can we see the all red map???...regular or blowfish pattern is fine with me as long as its ALL red!

[docbnj]

The undistorted maps are more informative, because they show that Kerry mostly won urban counties, and areas with large Black populations; he also won some areas with high Méxican and American Indian populations.

The exception would be New England, but even there it is the urban counties. Most of the countryside in PA went for Bush, with only areas around Pittsburgh, Erie, Wilkes-Barre, and Philadelphia going for Kerry. Without Philadelphia, PA would ahve been a landslide for Bush.

As in 2000, the high-crime areas went for the Democrats. I can see why they think that allowing felons to vote is a good idea: they expect the felons to be Democrats, and they are mostly correct for once on that score.

[bigbob]

This is a very interesting map. Can anyone offer a theory for the Kerry vote concentration roughly along the Mississippi River valley?

[mdittmar]

ahh,looks like a turkey.

oops sorry,thought this was one of those rorschach things.

[Arkinsaw]

This is a very interesting map. Can anyone offer a theory for the Kerry vote concentration roughly along the Mississippi River valley?

Mississippi Delta has a large minority population.

[Tench_Coxe]

Well, if helps shut the libs up by making their areas look larger, I'm all for it.

[BushCountry]