Back in April, data whiz Chris Dickersin-Prokopp created a map for Washington City Paper showing the median income for each Metro stop in the system. Now, Metro’s planning blog, PlanItMetro, supplements his effort with two maps of its own: one depicting income, the other race.

The income map looks very similar to Dickersin-Prokopp’s, with wealth concentrated in western D.C. and the western suburbs, poverty concentrated in eastern D.C., and moderate incomes at the Prince George’s County stops. Rather than median income, this map tracks the percentage of riders (by origin station, on a typical May 2012 weekday) who are low-income, with an annual household income under $30,000:

The second map shows something different: the percentage of riders at each station who are minorities, defined as anything other than white non-Hispanic. No Metro station is less than 22 percent minority, while the percentage at some reaches into the upper 90s. As we well know, there’s a strong correlation between race/ethnicity and poverty in the D.C. region. But there’s one area where this correlation falls apart: In Prince George’s County (and to a lesser extent the outer western suburbs), there’s a high percentage of minorities but a low percentage of low-income riders. This shouldn’t come as a surprise, as Prince George’s County is the wealthiest majority-black county in the country. Still, it does account for the main discrepancy between the two maps.