| 摘要 |
PURPOSE:To greatly shorten the distance and time for course calculation by retrieving initial courses in the course table according to the setting of a destination by a driver without any calculation and showing them to the driver, and calculating the best course extending to the destination point among the initial course when the initial course within a constant distance to the destination is obtained. CONSTITUTION:Road map data within a range including a starting point P are read out of a road map memory, and the destination point Q and a specific point PO close to the current position of a vehicle area set; and the course table is retrieved according to the setting of the destination point Q and specific point PO to obtain the initial courses d1...; and this procedure is repeated to obtain a series of initial courses as a part of the best course extending to the destination point Q and when information regarding the initial course within the constant distance to the destination point Q is obtained, road map data within the range including the terminal point of the initial course and the destination point Q are read out of the road map memory and the best course extending to the destination point Q is calculated from the initial course. |
