From the web developer who brought us maps of the city's tree species and toxic spills comes a map showing the city's real estate by greenhouse gas emissions, using city data to highlight the biggest offenders.

Under the city's Greener, Greater Buildings Plan, owners of single properties with more than 50,000 square feet (or multiple properties with over 100,000 square feet) must disclose their energy and water usage data each year. (Jill Hubley, the map's creator, says these buildings account for nearly half of the city's energy use.) Merging that data with city land use data, she created this map, in which greener buildings are coded in shades of teal, while energy-sucking sites are colored tan and brown.

In her initial observations of the trends going on in her map, Hubley points out that a lot of high emissions are clustered in the Times Square area. Some of these buildings, like the Crowne Plaza Times Square and the Grand Hyatt, have pledged to reduce emissions as part of the NYC Carbon Challenge, while others, such as notorious developer Extell's W Hotel at Broadway and 47th Street — one of the worst offenders — have made no such promises.

Hubley also notes that a number of high-emission buildings are owned by the New York City Housing Authority (NYCHA), such as the Alfred E. Smith houses on the Lower East Side and the J.P. Mitchel houses in the Bronx. However, there are also low-emission NYCHA buildings dotted throughout the map, and NYCHA got $100 million in city funds last spring to make energy-efficiency upgrades, so it's possible those brown patches will get greener over time.

There's lots more to see here — for example, NYU and Columbia, are pretty green, but a number of city hospitals are less so, and what's up with Stuy Town? Poke around for yourself and see if your building's on here.