1. A method for processing by a processor a 3-dimensional landmark providing a 3-dimensional representation of a 3-dimensional real world object located at a predefined geographic location, the method comprising the steps of: providing a data set containing the 3-dimensional landmark, determining by a processor a largest continuous horizontal surface of the 3-dimensional landmark, and storing the determined largest horizontal surface as road traffic area of a road network used by a user when moving on the 3-dimensional real world object.