Millions of people live in places where there are no maps at all. When a disaster strikes there, this will cause problems that you can’t imagine. What if you could fix that? And two million others would do it with you? That’s OSM. Humanitarian aid was one of the goals when OSM was founded.
Blake works for HOT (Humanitarian OpenStreetMap Team), an organisation that helps people to improve OSM of areas that may be facing disasters (where can you expect floods, power outages, …) and that don’t have maps at the moment, e.g. slums. They mainly mobilize and train volunteers. They do this from their homes or school or even office. This is often done in mappatons. They start from areal images, indicate the buildings on them so you get vector data. That data can be put into GIS tools. There is also mapping on the ground: what is the building used for (school, hospital, …), administrative boundaries.
To organise all this, there is a tasking manager that keeps track of where mapping is needed, split up the area, which areas have priority. Mapping is usually done in two passes, to weed out mistakes and polish it. This is important to make sure there is a good confidence level on the data, or to say how much confidence it has. The work is also split into tasks, e.g. one team concentrates on roads, another team concentrates on buildings.
Example: Gueckedou in Sierra Leona. On a map looks like a pretty small village, but it’s actually a town of 250K people. With the Ebola outbreak, 244 volunteers mapped the area in 5 days, mapping 90000 buldings. Outside of emergencies: Dar Es Salaam was mapped in 6 months. Most of that time is training hundreds of university students to do the mapping on the ground. They are now a stand-alone organisation, which is now helping to map Mozambique.
The management tool feeds its information into the OSM editing tool (e Mapping is usually done in two passes.g. josm) to tell the mappers what to do.