With over 14 million people, half of which are squatters or slumdwellers, Mumbai is indeed a "maximum city" according to Schuyler Erle. The obstacles to constructing housing for Mumbai’s huge homeless population pile up long before any plan is drawn: to submit a redevelopment project the area is required to be mapped, and before you can make a map you need reliable data.
Erle describes a daunting challenge to mapping Mumbai: the only data available consisted of many very detailed, but hand-drawn maps, which had been vectorized with no common geographical reference. One of the steps required to go from there to a complete geographical dataset, recounts Erle, involved people covering Mumbai using GPS devices to gather control points.
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