The users who modified data in the area were divided into five classes according to their OSM history:
- EB: existing users who modified the area only before the event
- EBA: existing users who modified the area both before and after the event
- EA: existing users who modified the area only after the event
- AO: users registered to OSM after the event who made the first edit outside the study area
- AI: users registered to OSM after the event who made the first edit inside the study area