Thursday, January 24, 2013

Census Dotmap

When visiting yesterday, I was excited to find this article about a dot map that Brandon Martin-Anderson of MIT made using Python scripts and US and Canadian census data. Unlike most dot density maps, where a single dot represents many people (the New York Times has an excellent map showing the distribution of racial and ethnic groups), this census dot map gives every person in the United States and Canada their own dot. The result is a beautiful visualization that tells us a lot about North America.

The lower 48 states and Canada

In spite of technological advances, we can see that settlements in North America are still largely determined by natural land forms. Zooming in to the Alleghenies in Pennsylvania, we can see the contours of the ridges and valleys. Rivers and lakes are also well defined: in almost every case, each bank of a major river is densely settled. It is also interesting that as we travel west, the settlements increasingly trace major highway routes.

Finally, this map shows the variety of experiences lived by Americans and Canadians. As you zoom into major cities, you see how densely populated blocks are defined and separated by major roads and physical features. We also see how densely populated the Eastern Seaboard has become, and how sparsely populated the Nevada desert and Canadian arctic remain.

You can visit the map at and change the zoom level. If you zoom in far enough, maybe you can find your own dot!