Cartogram
A cartogram is a distorted map where the area or other visual encodings are used to represent the quantity associated with each region.
History
- Wallace, J. W. Population map for health officers. Am. J. Pub. Health 16:1023, 1926
There was another design of cartogram in 1934 by Erwin Raisz (Geographical Review, Vol. 24, No. 2 (Apr., 1934), pp. 292-296) and this also looks like an almost proper treemap.
Examples
- http://www.worldmapper.org/
- Types of cartogram
- election map 2008
- http://show.mappingworlds.com/world/
- http://www.datavis.ca/gallery/bright-ideas.php
- http://mbostock.github.com/protovis/ex/cartogram.html
- http://mbostock.github.com/d3/ex/cartogram.html
- Another US election, another “Land doesn’t vote, people do” style map showing the election results - Dorling cartogram’s (with circles) drawback is that we cannot identify the regions well. Still, it can be useful to make this point.
- A better U.S. house election results map? a nice Observable notebook that shows the process of creating a cartogram that utilizes the Voronoi diagram.
Software
- http://www2.imperial.ac.uk/~mgastner/cartogram/cartogram.html
- http://www-personal.umich.edu/~mejn/cart/ - source code
- http://scapetoad.choros.ch/index.php
Articles
- Why we didn’t use a cartogram in the Brexit map - a good summary of argument against the cartogram.