Plan Metro

Next week I'll be blogging from Paris, so in honor of the The City of Light, let's take a look at a map of the Paris Metro.

Subway plans are among my favorite maps, although they're not really maps in the strictest geographic sense. Because the designers of rail transit maps often deliberately distort distances for the sake of aesthetics and readability, geographers sometimes refer to such rail plans as linear cartograms.  Nor are distances the only spatial relationships routinely altered on these maps.  Compare the metro diagram above to an actual map of Paris below, and you'll see what I mean.  Note, for example, how Ile de la Cite in the center has been rotated counterclockwise by 45 degrees, and the way in which the Seine's channel has been heavily stylized.  If you were to overlay the plan above on the map below, you would also find that the locations of subway stations and the distances between those stations have been altered in the metro plan.  For the average subway rider, knowing the exact geographic location of a stop is less important than knowing what stops precede it and follow it.  For an even more glaring example of the geographic distortions of subway diagrams, compare these maps of the London Tube.

Most of the world's major metropolitan areas now use some variation of the diagrammatic style used in Paris, with the significant exception of New York City, which continues to prefer a more geographical approach.

For an enjoyable introduction to the underground world of urban rail maps, try Mark Ovenden's Transit Maps of the World.  For an on-line resource, visit Robert Reynolds's The Subway Page, where you can check out some of my personal favorites, including maps of London, Moscow, and Tokyo.