OpenStreetMap (OSM) is a project to create a free editable map of the world. Two major driving forces behind the establishment and growth of OSM have been restrictions on use or availability of map information across much of the world and the advent of inexpensive portable Satellite navigation devices.
The maps are created using data from portable SAT NAV devices, aerial photography, other free sources or simply from local knowledge. Both rendered images and the vector dataset are available for download under a Creative Commons licence.
The OpenStreetMap approach to mapping was inspired by sites such as Wikipedia; the map display features a prominent "Edit" link and a full revision history is maintained. Registered users can upload GPS track logs and edit the vector data using free GIS editing tools like JOSM. Various mobile applications also allow contribution of GPX tracks to the OSM project.