PURPOSE: To update a display map accurately without delay with respect to the present position of a vehicle, by starting the updating of map data with the movement of the vehicle in correspondence with the speed of the vehicle.
CONSTITUTION: A running distance detector 1 detects the running distance of a vehicle. A running direction detector 2A detects the running direction of the vehicle by utilizing, e.g., geomagnetism. A running direction detector 2B obtains the relative bearing of the running direction of the vehicle. These signals are inputted into a signal operating device 3. Device 3 computes the accurate present position of the vehicle and receives the map data of the present running position from a data memory device 4. The result is displayed on a display device 5. On a screen 51 of the device 5, e.g., roads 53W55 are displayed. The road 55 disappears at an end surface 52 of the display part. Protrusion boundary lines A and A' of the road 55 and reading boundary lines B and B' are changed into A and B or A' and B' in correspondence with the speed of the vehicle. Thus the smooth updating of the map without delay in the updating of the map data can be performed.
MATSUOKA YOUJI
ENDOU AKIRA
TAKEZAKI JIROU
SHIRAI YUTAKA
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