I found this interesting:
Most of us are, by now, familiar with the maps the TV channels and web sites use to show the results of the presidential election. The states are colored red or blue to indicate whether a majority of their voters voted for the Republican candidate, John McCain, or the Democratic candidate, Barack Obama, respectively. Looking at this map it gives the impression that the Republicans won the election handily, since there is rather more red on the map than there is blue. In fact, however, the reverse is true the Democrats won by a substantial margin. The explanation for this apparent paradox, as pointed out by many people, is that the map fails to take account of the population distribution. It fails to allow for the fact that the population of the red states is on average significantly lower than that of the blue ones. The blue may be small in area, but they represent a large number of voters, 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 are rescaled according to their population. That is, states are drawn with size proportional not to their acreage 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. On such a map, for example, 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 2008 presidential election results on a population cartogram of this type:
We can represent the effects of the electoral college by scaling the sizes of states to be proportional to their number of electoral votes, which gives a map that looks like this:
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:
However, this map is still somewhat misleading because we have colored every county either red or blue, as if every voter voted the same way. This is of course not realistic: all counties contain both Republican and Democratic supporters and in using just the two colors on our map we lose any information about the balance between them. There is no way to tell whether a particular county went strongly for one candidate or the other or whether it was relatively evenly split.
One way to improve the map and reveal more nuance in the vote is to use not just two colors, red and blue, but to use red, blue, and shades of purple in between to indicate percentages of votes. Here is what the normal map looks like if you do this:
And here's what the cartogram looks like. As this map makes clear, large portions of the country are quite evenly divided, appearing in various shades of purple, although a number of strongly Democratic (blue) areas are visible too, mostly in the larger cities. There are also some strongly Republican areas, but most of them have relatively small populations and hence appear quite small on this map.
As this map makes clear, large portions of the country are quite evenly divided, appearing in various shades of purple, although a number of strongly Democratic (blue) areas are visible too, mostly in the larger cities. There are also some strongly Republican areas, but most of them have relatively small populations and hence appear quite small on this map.