OpenStreetMap (OSM) is a free, editable map of the world, created and maintained by volunteers and available for use under an open license. Anyone can use OSM to provide maps, directions, and geographic context to users around the world. In the 12 years of OSM’s existence, editors have created and modified several billion features (physical things on the ground like roads or buildings). As new users join the open mapping community, more and more valuable data is being added to OpenStreetMap, requiring increasingly powerful tools, interfaces, and approaches to explore it.