We already knew that the topography of New York real estate is changing—formerly unhip neighborhoods have become hip, resulting in skyrocketing rent, and already pricey neighborhoods have become pricier still. But which neighborhoods are gentrifying the fastest?

To answer this question, we asked Property Shark to prepare a nifty map, which measures the median home sale price in each census tract, divided by the median household income.

The dark purple splotches represent places where people are paying a lot for real estate in places where their neighbors make relatively little money. While neighborhoods like NoLiTa, Prospect Lefferts Gardens, and Sunset Park are easy to explain (Hi, gentrifying hipsters!) there are several others that have us trawling Google maps for an explanation. One tiny purple island along Kissena and Parsons boulevards in Flushing seems to be adjacent to Queens College—overpriced student housing, perhaps? Others are totally inscrutable. For instance, that splotch in East Williamsburg- perhaps an artifact of bad data?

Click around the map yourself here, and when you find out what's going on between Edgecombe and St. Nicholas avenues (it has to be the park, right?) be sure to let us know.

N.B.: Property Shark explains the data we used: "To compile the data we used census tracts and we’ve only taken into account the residential sales closed in 2012 and 2013 with sale prices over $50,000. Also we only mapped census tracts that had 4 or more sales in order to have a median sale price as accurate as possible. Due to these filters and also because some census tracts comprise only rentals or other commercial properties, you will find gray areas on the map with no data available."