Click on map to see where New York City’s fruits and vegetables come from.

In 1906, Joseph Pulitzer’s original New York World published a feature illustrating the city’s daily consumption of various food items and their average prices, citing a USDA “Year book” as its source. We were intrigued by the idea of updating it more than a century later. But these days, it’s difficult to piece together a comprehensive look at New York’s food supply. While multiple sources of data exist, they are too broad or too specific, fraught with caveats and difficult to relate to one another. A lot of information is privately held.

Originally, we looked at Freight Analysis Framework data from the Federal Highway Administration, which provides a view of where New York City’s food comes from and how it gets here. But the transportation data is limited in a number of ways. Food that travels internationally to a United States city is often counted as domestic when it is then shipped from that city to other parts of the country. Products that undergo some type of transformation during their travels — nuts baked into cookies, for example — are often double-counted, falling into one category when raw and another in their processed state. Food items are grouped into very broad categories—like “live animals/fish,” “cereal grains” and “other agricultural products.”

The New York World’s 1906 infographic on New York City’s food consumption.

Enter the U.S. Dept. of Agriculture. In the wee hours of the morning, three USDA reporters head out to visit the vendors at the Hunts Point Terminal Produce Market. For hours, they peer at boxes of fruits and vegetables, jotting down numbers in spreadsheets, asking salesmen about the day’s prices and collecting scraps of paper with notes from the wholesalers. The vendors there are not required to report any information to the USDA, though on any given day about 80 percent of them do.

When the reporters return to their offices in the early afternoon, they turn those notes into a close-to-comprehensive set of data about where produce entering the market is coming from and how much the area’s grocery stores, restaurants and caterers are paying for it. The USDA calls it Fruit and Vegetable Market News , and it offers one of the more detailed glimpses into the sources of New York City’s food supply. We used this data to map out the origins of more than 170 different food items by season along with their average market price.

First, we grouped together results for similar items — for instance, Gala apples and Fuji apples show up in our database as just “apples.” In order to make the data relevant for consumers — who measure produce in pounds, not “film bags loose“ (carrots) or “wirebound crates” (corn) — we then converted the measures, with the help of the USDA’s list of standard approximate net weights.

Once we had each container’s weight, we calculated the approximate average price per pound for all the different grades and varieties for that type of produce. USDA Market News tallies both the lowest and highest price at the market for each commodity each day. Our map uses the lower of the two values.

We used Google Refine to handle the weight conversions and to add state and country codes corresponding to the origins listed in the USDA database.

The data is housed in four database tables, one for each season, and is powered by CartoDB. We’re using Leaflet’s API for our map.