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Report by Daniel Specht

The DRC Mapathon was launched in response to a polio outbreak to give the World Health Organization and U.S. Centers for Disease Control and Prevention an idea of where the population was located within the Democratic Republic of the Congo (DRC). The outbreak was the first in the DRC since 2000. Much of the area was poorly mapped, so the strategy was to map structures as points, disregarding the size and shape, as a proxy for population. This allowed people at all skill levels to participate.

In ArcGIS Online, the map of the area was tiled, and each tile was color coded to indicate whether it was (1) unmapped, (2) mapped but unvalidated, or (3) validated. As a validator, I would check out a tile (to ensure that no one else validated the tile at the same time), compare the point layer to the imagery layer and add, move or delete points as necessary. If the mapper was seriously off-track, I’d notify one of the staff so that they could counsel the mapper.

Color-coded tiles within the ArcGIS Online digitizing application

In addition to helping to eradicate polio (the outbreak was contained), we got to learn about some of the difficulties of this sort of mapping, such as structures hidden under trees and structures that shared a roof with other structures. Most of the structures were homes, although many were commercial structures or outbuildings. In the end, we mapped almost 400,000 structures.     

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