Saturday, January 26, 2013

Mapping Density with Dots

One of the coolest maps I've seen in a long time is the Census Dotmap, by Brandon Martin-Anderson. There is absolutely no base map at all--no roads, no topography, no political boundaries... nothing. Instead, there is simply one dot for every single person counted by the 2010 US Census and 2011 Canadian Census. As you zoom into an area, the variations in density get clearer and clearer.

It is amazing how natural features such as mountain ranges and rivers are so visible, despite the spartan nature of the map. Major population patterns are clearly visible, such as the megalopolis of the northeast, the hub and spoke pattern of big cities and small towns in the Midwest, and the dramatic drops in population in the plains, Rockies, and deserts.

It is very interesting to note how many of the densest cities are actually sparsely populated at the very center (due to the dominance of office space). Those central cores, however, are often surrounded by an extremely dense belt of population. Nuances like this are often lost in color-coded density maps based on larger geographic increments.

If I had one wish for a future enhancement, it would be for past censuses to be added. It would be really educational to pick an area and see how the present patterns vary from those of 50 or 100 years ago. Central Detroit comes to mind, as do the outer areas of metropolitan areas. If you could go back far enough in time, it would be a really dramatic and informative way to see the westward expansion of the United States. Such a project would be an enormous and daunting undertaking, though.

Kudos to Mr. Martin-Anderson on his awesome creation. This useful resource can be found here.

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