| 摘要 |
PURPOSE:To always display an area where a moving body is present, by displaying a map showing a current position of the moving body based on map data retrieved by a map data-retrieving means. CONSTITUTION:A map data-retrieving means 11 retrieves map data of the periphery of a moving body when a GPS receiver (current position-detecting means) 2 detects a current position of the moving body. If the GPS receiver informs it impossible to detect the current position, the retrieving means 11 operates a moving distance of the moving body from that time point. In other words, a system control means 15 retrieves map data of the periphery from a map data memory means 12 when the current position of the moving body is detected by the receiver 2. On the other hand, when it is informed and output that, the measurement is impossible, the system control means 15 instructs a moving distance-operating means 14 to calculate the moving distance of the moving body. A display means 16 displays a map showing the current position of the moving body at a data display means 18 on the basis of the map data from the means 11, and scales down the map in accordance with an increase of the moving distance of the moving body. |
