| 摘要 |
PROBLEM TO BE SOLVED: To decimate nodes on a recommended route when a convenient map is formed. SOLUTION: When a recommended route is determined by a route searching unit 6, a priority setting part 15 sets a priority for all nodes on the recommended route. A first decimating section 16 decimates nodes of minimum priority sequentially from all nodes on the recommended route to leave nodes of the same number as a reading constant, reads out the point data of these nodes from a map data memory 3 and stores the point data in a display memory section 19. After the priority is reset depending on the decimation conditions, a second decimating section 17 decimates nodes of minimum priority sequentially from reset point data stored in the display memory section 19 to leave point data of same number as a display constant. A forming section 20 forms a convenient map by arranging the point data of the same number as the display constants stored in the display memory section 19 and displays the map on an output unit 9. |
