For cartographers of cities, it may seem like that everything that there is to be mapped has already been mapped. Pick up the latest Thomas Guide of Los Angeles, for example, and it’s all there in painstaking detail.

But cartographer Joseph K. Lee and interaction designer Benedikt Gross have proven that there’s still quite a bit of uncharted territory even in 2013. With “The Big Atlas of LA Pools,” they’ve just mapped, for the first time, well, the outlines of 43,123 of L.A.’s pools.

The idea started when Gross flew to the U.S. for the first time for graduate school. “He imagined L.A. to be a barren desert with all sorts of water issues,” Lee explains. “As he flew into LAX, he saw a grid of turquoise pools out the window and was just sort of amazed.”





Gross was inspired to try to find all of the pools, but didn’t know how. Six months later, at MIT’s Sensable Cities Lab, he met Lee–an L.A. native with a background in remote sensing and cartography–and over a lunch conversation, the two decided to take on the project. “It all sort of started from there with this sort of frivolous idea–can we find all the pools in L.A.?–and then it quickly turned into something else,” Lee said.

They began with aerial imagery from the U.S. Geological Service. “We thought this is going to be easy, we can start with this data and just run it through some computer magic, and boom, we’re done and we’ll have nice beautiful images,” Lee said. “It turned out that it wasn’t so simple. The code just gave us digital noise and an ugly mishmash of lines.”

Next, they decided to try outsourcing the problem, and turned to a service in India that turns bitmap images into vectors. “After a week or two, we had gotten back 65,000 hand-drawn pools,” Lee said. “At which point we thought, okay, this is no longer this fun project, it’s really kind of this scary thing. Humans are involved, it’s globalization and cheap labor exploitation–the epitome of that whole thing. We decided we really need to make this into a meaningful project to raise awareness about these issues, and basically how easy it is to do this kind of thing.”

After all 43,123 pools were outlined, Lee and Gross used Amazon’s Mechanical Turk cheap labor crowdsourcing service to verify that all of the pools were in the correct place, and then checked the data themselves until they ended up something a definitive guide to the pools in the area. Then, curious about what other data was out there, they started exploring more online.