Every single day Red Cross, UN and NGO volunteers and employees are active in areas where help is needed. In order to organize this efficiently good maps are a necessity. However, these are often not available. With modern technology and methods it has become feasible for trained volunteers to contribute to the creation of maps within short time frames.Currently in mapping we often use freely available images from satellites, airplanes and drones. Images taken on the ground from vehicles or on foot are also common practice. We know exactly where these pictures are taken thanks to the use of GPS. Through the use of open software we are able to draw the maps with a high degree of accuracy without additional costs (ID editor, JOSM, QGIS). Using Open data (OpenstreetMap) means that it is accessible for everybody to draw, update and enhance the maps.We combine mapping data with data on earthquakes, hurricanes, floods, drought, and outbreaks of disease, etc, alongside data about the natural environment and about local community resilience. Through this we can plan and organise operations and necessary projects.For missing maps everyone is invited to map individually or in groups. Mapathons are organized all over the world where thousands of people come together to map a requested area in need. The team at 510 coordinates these mapathons : preparing an area to be mapped, giving an introduction, helping the people with mapping, organising the validation and supporting local people to improve and sustain their regional maps.