| 摘要 |
PROBLEM TO BE SOLVED: To increase road data which are used to calculate a return route without increasing the time required for calculating the return route and to enhance the route quality. SOLUTION: A return point is used as a cost-calculation starting point 1, and a cost calculation is executed so as to be stored. When a route is deviated, a return route 3 is set on the basis of a cost calculation result by connecting a link in which the total cost up to the return route 1 from a present position 2 is reduced. The Dichstrer method comprises a characteristic that, after the completion of a cost calculation, a route to all points in a calculation range from a calculation starting point can be calculated. As a result, the return point 1 is used as the calculation starting point, and the cost calculation is executed, and by using its calculation result, the route up to all the points in the calculation range from the calculation starting point 1 can be calculated. Consequently, the setting processing operation of the return route can be performed in a very short time when a route is deviated actually. |
