Mapping historical subway ridership levels

I love subway maps and maps about subways. I have an extensive collection of historical New York City subway maps at home and a few from other systems around the globe as well. Recently, though, something else piqued my attention. Mike Frumin, that man behind Frumination got his hands on historical subway ridership figures from every station in the system. Not only has he made the data readily available, but he has mapped it through a series of sparklines. He offers up his analysis of the map as well.

Meanwhile, two other programmers have taken the data and turned it into colorful visuals as well. This flash map looks good but distorts the station-by-station data. The other, found here, doesn’t look as sleek but is presents a far more rigorous examination of the data. Check it out.