OpenStreetMap
OpenStreetMap (OSM) is a United Kingdom-based non-profit project that is building a free digital map of the world. Online volunteers, or remote mappers, contribute data that creates an accurate, detailed and up-to-date map. There are many free maps on the Internet, but the underlying data in many other maps is not available for the public to use due to legal and technical restrictions. OpenStreetMap opens up the map and the data to the public and makes it free to modify and use under an open license (Open Data Commons Open Database License 1.0).