The Big Atlas of LA Pools
Mappers spot all the pools in L.A. Basin
The two men started by sending two sets of satellite photos from the federal National Agriculture Imagery Program — one a true color composite, the other a false-color version to make the pools easier to spot — to a crowd-sourcing service in India. They paid workers $300 to draw the outline of every pool shown in the pictures onto a computer program.
They then spent an additional $350 to have the initial count double-checked by Amazon Mechanical Turk, another crowdsourcing service. Workers there inspected images of each swimming pool’s location to confirm it was a body of water and not, say, a house with a blue roof.
The duo used eight publicly available databases, including latimes.com’s Mapping L.A., for the project. Other data sets used included the county’s parcel boundaries service, the Los Angeles County sheriff’s crime database, the assessor’s data set and a database that contained those donating money during the Proposition 8 campaign on gay marriage and the Megan’s Law list of registered child molesters.
[...] Lee agrees: “The feeling that this is occurring with armies of people and computers doing the exact same exploration at a higher scale is frightening.”