Millions of people worldwide live in poorly mapped areas. When conflict, disease, or natural disaster strikes, the humanitarian community often scrambles to generate map data as it responds. The The Missing Maps project aims to solve this problem with an ambitious effort to put the world’s most vulnerable populations on the map.

Brighter areas are more densely mapped but don’t always correspond with population size

A collaboration between the American and British Red Cross, the Humanitarian OpenStreetMap Team (HOT), and Medecins Sans Frontieres, Missing Maps is rallying volunteers to trace satellite imagery and gather on-the-ground data. Better maps of vulnerable areas help NGOs and governments prepare for humanitarian crises before they happen.

But where to start mapping? Mapbox is applying the same analysis used by our data team to help prioritize Missing Maps work. Our code looks for areas with low feature counts in OpenStreetMap but high satellite imagery data density (a rough proxy for lots of buildings and roads) to identify under-mapped areas. We can then compare the resulting locations with various vulnerability metrics like public health data, infrastructure quality, food security, and disaster preparedness.

As an example, we identified these map tiles from Karachi, Mumbai, Surat, and Yangon as good Missing Maps tracing candidates:

Lots of roads and buildings, but not many are traced in OpenStreetMap (purple)

We’ll be delivering the Missing Maps team this longer list of priority areas that lets volunteers click through to edit the map. If you want to help build the code that powers the search for under-mapped areas, ping @brunosan on Twitter or follow the repository on Github.

Want to get involved in Missing Maps? Attend one of the launch events. You’ll meet fellow mappers and learn how to map using tools like iD Editor. Mapbox has teamed up with Code for America to host the San Francisco mapathon and will be represented at the Washington, DC event, so come say hello. If you can’t make it in person, you can contribute remotely to one of the Missing Maps activations in the HOT task manager.