Maps: Essential Tools for Contact Tracing


CDC responders using OpenStreetMap data on a tablet to help navigate to this small village between Kambia town and Kabaia in Kambia District, Sierra Leone

Teams responding to the Ebola outbreak in West Africa often faced the challenge of finding people and communities living in remote areas. Maps of these regions often didn’t exist, or were incorrect or outdated. Basic information—locations of houses, buildings, villages, and roads—was not easily accessible.

To help the response effort, volunteers from around the world used an open-source online mapping platform, called OpenStreetMap (OSM), to create detailed maps of Guinea, Sierra Leone, Liberia, and parts of Mali. The Humanitarian OpenStreetMap Team (HOT), a U.S.-based, non-profit organization that uses OSM data and tools to prepare and respond to humanitarian disasters, took the lead.

Because OSM data can be downloaded for free, volunteer mappers generated data useful to CDC and other agencies involved in the Ebola response. Over the course of the epidemic, more than 2,500 volunteers mapped more than 750,000 buildings and hundreds of kilometers of roads, resulting in detailed maps of affected West African communities. Not only did these maps help first responders and other organizations around the world, they also contributed to the national information infrastructure essential to the recovery and rebuilding of affected regions.

Lash, Ryan

Dr. Ryan Lash, who was deployed to Freetown, Sierra Leone, and provided mapping and geographic information system support, discusses the use of OpenStreetMap during the outbreak. (Transcript)

The CDC Situation Awareness and Geospatial Research, Analysis and Services Program (GRASP) teams produced detailed map atlases, such as this one, to aid Ebola responders. These maps were compiled with data and imagery from OpenStreetMap and Digital Globe.


N’Zéréekore, Guinea Map Set, October, 2014

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To further the geographic impact of Ebola, listen to oral histories on the Mapping Ebola Stories page.