| 摘要 |
PURPOSE: To provide a navigation device in which search for the optimum route is carried out while considering existence of grade crossings and waiting time at the grade crossings can be reduced as much as possible. CONSTITUTION: In the road data, existence of grade crossings is stored while timetables for main railway stations are stored. In estimation of the distance along road between crossroads in search for route, weighting corresponding to the number of passing trains per unit time is carried out to a road on which a grade crossing is situated. For example, when a grade crossing between the Shinjuku station and the Yoyogi station is situated on a road of the road number (2), the total number of trains (clockwise trains and counterclockwise trains of the Yamanote loop line and up trains and down trains of the Chuo line and the Sobu line) starting from or passing through both stations are counted from respective timetable data. The number of passing trains per unit time is computed by dividing the total number of trains by a time from the first train to the last train, and a coefficient corresponding to the value of the number of passing trains per unit time, for example, 10 is obtained from a weighting data storage unit so as to be applied to multiplication for the road of the road number (2). In this way, selection is carried out while considering a road with an actual length of 300m as a road with a length of 3000m in the optimum route search. |
