1. A method implemented at least partially by a processor, the method comprising: collecting a sequence of global positioning system (GPS) points from route-oriented vehicle logs; identifying geographical locations from the route-oriented vehicle logs, the geographical locations representing locations where route-oriented vehicles travelled as recorded in the vehicle logs; extracting route-oriented vehicle trajectories from the route-oriented vehicle logs, the route-oriented vehicle trajectories representing individual trips; and constructing a landmark graph based at least in part on the route-oriented vehicle trajectories by: associating each route-oriented vehicle trajectory to a corresponding road segment; determining a first frequency that a first road segment is visited by the route-oriented vehicles and at least a second frequency that other road segments are visited by the route-oriented vehicles, the first frequency being determined based on a number of the route-oriented vehicle trajectories that are associated with the first road segment, and the second frequency being determined based on a number of the route-oriented vehicle trajectories that are associated with the other road segments; comparing the first frequency to the second frequency; and identifying a landmark, the landmark being the first road segment when the first frequency is greater than the second frequency.