| 摘要 |
PURPOSE:To surely view an optimum guiding path on a branch point by detecting the approach to the branch point by means of comparing a distance from a current point to the branch point with a threshold and enlarging and displaying the road map of the periphery of the branch point and the optimum guiding path. CONSTITUTION:When the distance between the position of a vehicle and the branch point, detected by a position detection processor 4, goes to the previously set threshold or below, the display selection part of a display controller 6 judges that the vehicle approaches to the branch point and enlarges to display 5 said branch point and the optimum guiding path. Namely, a window is set on the right half of a screen and the position of the vehicle is displayed by being positioned in the lower part of the window, so that a driver can instantaneously view the optimum road in the advancing direction of his own vehicle. By considering an estimated time necessary for reaching the branch point and an error in detecting the position, included in the device 4, the detection of the approach to the branch point can be performed. When the vehicle comes a certain distance away from the branch point, it is judged that the vehicle has passed the branch point. Then, the position of the vehicle and the road map are displayed in a specified scale based on map displaying data. |
