Chicago train coverage

El coverage in Chicago (click to enlarge).

The last time I rapped at you, I talked about Métro coverage in Paris. I felt like Paris was exceptionally well covered by the Métro, and I used math to prove that basically one is never more than 700m from a Métro station in the city. How, though, does that coverage compare with Chicago? Would you be surprised if I said that Chicago ends up looking rather awful in comparison? How much worse, would you guess? If 700m is the maximum in Paris, what would you guess is the maximum distance from an el stop in Chicago? 1km? 2km? More?

After wrangling a bit with the GIS data available from the city itself as well as the CTA data from Steven Vance, I can build a simple buffer map much like the Paris map from the previous exercise, and the results? They ain’t pretty.

It is a bloodbath, in fact. Whereas in the previous exercise, the buffers were 250, 500, and 700m from the Métro, In this map on this post, the buffers are 1, 2.5, and 5km from the stop. In other words, everything that is dark purple is between 2.5 and 5km from a CTA El stop. Areas that are tan are parts of Chicago that are over 5km from a CTA El stop. But even if we just look at the 2.5km discs, we see that what feels like a third of the South Side is abandoned when it comes to the El. Pullman, Beverly, Rainbow Beach. All these neighborhoods are, literally, miles from the El. Even the parts of Hyde Park east of the Metra tracks (hot pink) are over 2.5km from the Green Line.

Ah, but what about the Metra, then? Surely some of these coverage gaps can be accounted for with the Metra, right? OK, let’s add them, as I included RER stations in my Métro map. And, fair enough, once you add in the Metra, nearly none of Chicago is more than 2.5km from a train station of some sort (dark blue for CTA, dark green for Metra). But, still, I’m using largely inflated scales for these maps to try and get something like the coverage of Paris. So, as a final map, I’ll dial the buffers back down to Parisian size: 250m, 500m, and 750m, just so you can compare, side-by-side, Parisian coverage with Chicagoan coverage.

Tags: Chicago, GIS, Public trans snob, Public Transportation, Quantum GIS