I don’t think I’ve encountered Andy Woodruff’s Cartogrammar blog before, but his latest entry, about his latest project, is a beaut: “Last month, as I was driving through Ohio,” he writes, “it dawned on me: There are 88 counties in this state. There are 88 keys on a piano. I don’t know anything about music, but holy crap, I have to make a map based on this coincidence.” The end result is a Flash map called Ohio is a piano:

The premise is simply that each of the 88 piano keys is assigned to a single Ohio county. How the keys are mapped to the counties depends on a specified data attribute: the notes and counties are ordered by that attribute and then linked to one another. For example, if the chosen attribute is population, the county with the lowest population is assigned the lowest-frequency piano key, the county with the highest population is assigned the highest-frequency piano key, and so on. The data I have here are a little out of date, but that doesn’t matter for demonstrating the idea.

This is a very, very strange way of presenting data, but as a piano player myself I have to confess that I can’t help but love it. Via Cartophilia.