It’s beyond me how I ended up on the ArcGIS mailing list, but every so often I get one of their newsletters that contains the latest and greatest cartography tools and research.
I usually scan the magazine pretty quickly, but the article by Huang and others in the October 2013 issue caught my eye. (A slightly different version can be found here). In it, the authors describe a new visualization technique they call “Ring Maps.” The visualization is essentially a choropleth map surrounded by a ring that denotes temporal data for each geographic subregion (e.g., counties within states). Here’s the central image:
The technique doesn’t work for me and not because of the knock against all things circular. The rings don’t help me pick out temporal patterns; instead, the chart feels cluttered and difficult to decipher. Perhaps the technique would work well in cases where certain areas stand out; for example, in the image above, if one county was all red.
Let’s be honest—this is essentially just a time-oriented radial chart with a map in the middle. I’m all for pairing chart types together, but if you want to pair geography and time, why not pair a map and a line graph? Or plot changes over time in the map itself? I’m no cartographer, but there’s got to be a better way.