Openstreetmap (OSM) is free, editable map of the world crafted entirely by croudsourcing approach. To build an intution for this wiki-like map, I would like to take an example from the recent earthquake in Nepal. In only 48 hours after the quake, over 2000 volunteers mapper responded to the crisis by quadrupling the road mileage and adding 30% more buildings. OSM is the biggest crowdsourced project ever. However, since the OSM data is human edited, it comes with it's own challenges for cleaning.

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