OSM mapping of building damage - review and prospects after Chido in Mayotte (sotm2025)

On December 14, 2024, the territory of Mayotte, a French department of more than 300,000 inhabitants made up of several islands between Africa and Madagascar, was hit by the passage of Chido, the most violent cyclone it had seen in more than fifty years. Pleiades imagery taken in the following days, between December 17 and 24, were posted online and released for the OSM contribution. These images provided an opportunity to compare the situation before and after the disaster and to assess the damage to thousands of buildings. The presentation will explain the chosen methodology, which was inspired by the few examples previously produced in OSM and by a methodology developed by researchers at the Harvard Humanitarian Initiative. It will briefly show the editing workflow, which uses a specific preset and cartographic style in JOSM and relies on detailed descriptions and videos in several languages. It will also analyze the results obtained and the statistics generated throughout the cartographic process. It will compare them with other post-Chido evaluations carried out remotely or in the field, but on smaller samples. Finally, it will look at the prospects for replication in other contexts affected by wind damage. Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/ about this event: https://2025.stateofthemap.org/sessions/RMVQF9/