| 摘要 |
PROBLEM TO BE SOLVED: To reduce the capcity of a memory storing map data by reading out map data according to a detected vehicle position from a memory housing map data, writing it in a memory storing display map data, and reading out display map data in order of address according to the veicle azimuth detected by a vehicle azimuth detecting means. SOLUTION: According to the detected signal of a vehicle position detecting circuit 1, map data of which specified direction is upward in the vicinity of the present position is read out from a CD-ROM 3 and written in a RAM 10 by a writing control circuit 8. A readout address control circuit 11 computes address order approaching to the RAM 10 according to the detected signal of a vehicle azimuth detecting circuit 2, and approaches to the RAM 10 in the address order in response to the vehicle azimuth so as to read out display map data. When the advancing direction of the vehicle is changed, it is detected by the vehicle azimuth detecting circuit 2, and according to this, the address order approaching to the RAM 10 is changed by the readout address control circuit 11. |
