File with an .OSM extension contains street map data stored in the OSM (Open Street Map) file, based on XML. Such record is based on nodes representing specific points, roads (which connect the nodes), and relations that may contain properties of given streets, points, objects or indicators.

There is an OpenStreetMap file entitled Planet.OSM, which contains a continuously expanded Earth’s streets database. They can be viewed and exported also via supporting FTP services. OSM files can contain data in different scales – representing a small fraction of space or the whole planet.