For a period of six months in 2010, I lived in East Harlem and worked in Prospect Heights. This meant riding the subway for about an hour every morning, and on those trips when I managed to stay awake, one of the most interesting aspects of the ride was watching the changing demographics of my fellow passengers as we moved from Harlem to the Upper West Side, then to Times Square and Penn Station, down to Tribeca and Wall Street, and from there into Brooklyn, passing through Brooklyn Heights, Downtown Brooklyn, and on to Prospect Heights. The traditional spin on New York has it that it’s not a segregated city, or at least it’s less segregated than other major American ones, like Boston and Washington, DC, because our public transportation jumbles us all together. But as anyone who’s ridden a line a long way knows, that’s not the full story.

Now The New Yorker has taken the increasing economic segregation of our city and visualized it. The magazine matched up median household income information from the 2011 US Census with nearby subway stations, creating maps of each line that spike and dip as the train moves from one stop, and one borough, to the next.

At first glance, the maps are both surprising and not surprising at all. Everyone knows Manhattan is the city’s richest borough, and that’s confirmed by the across-the-board peaks in the borough. But seeing just how big the jumps sometimes are — from a median income of $36,691 at Nostrand Ave. to $205,192 at Chambers St. on the A — is a bit shocking, not to mention depressing. The maps also make clear how concentrated and exceptional that wealth is: the 2, for instance, starts out at Flatbush Ave.–Brooklyn College, where median income is $37,073, and ends at Wakefield–241st St., $38,261, with only a handful of major peaks in between. The only line that basically tops out at $100,000 is the also the only one that doesn’t go into Manhattan, the G.

There are some puzzling points: here in the office, for instance, we couldn’t figure out how the Lorimer stop on the L had a higher income than the Bedford stop, which seemed on par with the median income at the Morgan Ave stop. But that may have to do with how the census data is mapped onto the subway stops locations, and it’s also good to keep in mind that these numbers reflect median, not average, income. Also, since we’re only following the subway, Staten Island is missing entirely; finding some way to incorporate the fifth borough would be illuminating.

Ultimately, these maps aren’t telling us much that’s new. But as with all data visualization, they’re crunching the numbers and making them easier to understand. Somehow visuals have a way of taking something we already know and may be inured to, and making it something we care more about.