You can’t stop Ebola if you don’t know where it is. Before organizations such as Doctors Without Borders or the Red Cross send health workers and supplies to countries affected by Ebola, they need maps to navigate and track cases, village by village.

But some maps of Liberia, Sierra Leone and Guinea are incomplete or have mistakes.

That’s where MapGive comes in. Powered by OpenStreetMap software, this effort by the Red Cross and the U.S. State Department allows volunteers to add roads and landmarks to maps used by health workers, even if a volunteer has never been there.

Thanks to collaboration tools like MapGive, more of us can play a role in the fight against Ebola.