Cartograms for Everyone

by KUMIKO YAMAZAKI on November 11, 2008 • apps cartogram: scapetoad • COMMENT

Trying to update more frequently here, we’ll see how I do.

By now, I’m sure we’ve all seen the election cartograms by Mark Newman. It’s received a lot of press this past week for good reason. He’s done a wonderful job describing how certain maps can look misleading at first glance and what can be done to more accurately display such data.

Fortunately for us mappers, there are a number of ways to create our own cartograms. My favorite is the free one I finally tested a couple days ago — ScapeToad. It uses the Gastner/Newman diffusion-based algorithm we see everywhere and comes with an easy-to-use interface. There is literally a ‘Create Cartogram’ button, can it get any easier??

The image shown is an example of the result after less than 5 minutes of work:

The above map is showing the number of Walmarts per 1 million people in each state. (Some of the New England states look more bloated than I expected). Ignore colors here, it’s representing cartogram size error. For stylization, I would suggest exporting as a shapefile and using a separate GIS application.

Enough blogging for the time being. I’ve entered the Apps for Democracy contest and the deadline is this Wednesday.. doh!