A navigation apparatus transmits current position information to a server. The server transmits course data to the navigation apparatus; the course data indicates a course that is predicted based on the current position information. The navigation apparatus corrects a subsequently measured current position on the course specified by the course data. The navigation apparatus transmits corrected position information indicating the corrected position to the server. The server distributes map data to the navigation apparatus; the map data corresponds to a specified area containing the corrected position specified by the corrected position information. Based on the received map data, the navigation apparatus displays a map near the corrected position on a screen of a display portion.