A free app for Android, by MOIB.

OpenStreetMap (OSM) is a free and Open collaborative map project that creates and distributes maps based on users’ contributions. The project began in 2004 and has accumulated more than one million volunteers who contributed to making it the most comprehensive digital map of the entire world. Its database of all the geographic data collected by explorers and mappers in their field trips is open for anyone to use or improve. You can use OpenStreetMap in your project to add or update features or just to explore. Contributors can edit and update tracks, routes, and points of interest through available editing methods.