But in its first iteration, Caliparks may have been a little too inviting. Because the app drew map data from the volunteer-edited OpenStreetMap, some of the trails it displayed were actually unauthorized by park officials. These “social trails” are often created by hikers wandering off the beaten path, or by folks using tools to intentionally carve out new paths or biking terrain. When other people follow these trails, it can be risky business.
“It can lead to erosion, impact species, and threaten wildlife habitat,” Nick Salcedo, a watershed manager in Marin County, told the Marin Independent Journal. “People can also get lost. We don’t patrol those trails as part of what we do.”
Park managers have tried to delete these trails from OpenStreetMap, but they often pop back up, thanks to OSM’s thousands of well-meaning mappers who work from aerial or satellite imagery. “The problem is the trail really exists,” Christensen tells CityLab. “So enthusiasts of open mapping—who believe the map should reflect the world—will put it back on the map.”