Cartograms

The Demers Cartogram uses squares rather than circles; this leaves fewer gaps between the shapes. The Demers cartogram often sacrifices distance to maintain contiguity between figures, and it will also sacrifice distance to maintain certain visual cues.

   A Dorling cartogram maintains neither shape, topology nor object centroids, though it has proven to be a very effective cartogram method. To create a Dorling cartogram, instead of enlarging or shrinking the objects themselves, the cartographer will replace the objects with a uniform shape, usually a circle, of the appropriate size

A Dorling cartogram maintains neither shape, topology nor object centroids, though it has proven to be a very effective cartogram method. To create a Dorling cartogram, instead of enlarging or shrinking the objects themselves, the cartographer will replace the objects with a uniform shape, usually a circle, of the appropriate size

The political conventions, followed by learning about the new TV series Newsroom, followed by the 9/11 anniversary have set my wondering again about media manipulation, distortion and omissions. I have written about this often; you may even remember the blog about the three little pigs in late July.

Watching the American electoral process play itself out is both fascinating and deeply disturbing. Not only does the process itself appear to be profoundly flawed, I cannot depend on my  perception and understanding of it! I need all the help I can get to make sense of it.

Sometimes a picture… or a graphic representation… may be worth the proverbial one thousand words. There is a paradox here. Sometimes a distorted map can give me  a better understanding of the real truth than a real map can give of a either the real or distorted truth.  Don’t just rattle off statistics… SHOW ME what this means, and convince me that it is meaningful.

Consider electoral maps. I find that often the most informative are not maps at all, but cartograms. A cartogram is a type of graphic that depicts attributes of geographic objects as the object’s area. Because a cartogram does not depict geographic space, but rather changes the size of objects depending on a certain attribute, a cartogram is not a true map. Cartograms vary on their degree in which geographic space is changed; some appear very similar to a map, however some look nothing like a map at all.

Seeing the various states coloured in red and blue has less impact on a geographically accurate map than on a map that also shows the state’s relative importance in the process. The two “maps” above are deliberately distorted to reflect just that. Which type do you find more useful? I think they are both valuable, each in a different way. The Demers cartogram is easy to read because it sort of looks like a “real map”, but this particular Dorling cartogram adds another level of information… the undecided.

This Youtube video demonstrates how useful a third type of cartogram can be. The distortion is sometimes quite disturbing, and certainly makes discrepancies easy to recognize and remember. Unfortunately, you must already have a very good knowledge of conventional maps and country locations to interpret them.

Here are more examples… some of them look like cartoon maps, drawn and colored by young children with serious problems in spatial reasoning and visual perception. But aren’t they fascinating!

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