This open-source alternative mapping service also publishes regular database dumps. We downloaded a full history dump of OSM contributions as of 24 February 2014, restricting this to the North American region as defined by Geofabrik 6 , which consists of the United States, Canada and Greenland. OSM groups individual changes to the map into changesets 7 when an editor saves their work. We used the timestamp of the last revision in a changeset as the time that the user saved the changeset. The resulting dataset (osm, changeset) contains 13,388,923 million changesets from 46,595 distinct users.