PURPOSE: To make a mobile station data display and a map data display easy to see and to momentarily grasp connections between maps before and after switching by selecting and displaying one of plural composite map data according to the direction of the switching to an adjacent area.
CONSTITUTION: In a figure, S1 indicates the range of map data of one divided area among all areas where mobile stations operate. Then S2-S5 indicate the ranges of map data composed of a half of map data on the divided area and part of map data on the adjacent divided area. Further, S6-S9 shows the ranges of m ap data composed of a quarter of the map data on the divided area and part of the map data on the adjacent area. When the display is switched to the adjacent area on the east side of the currently displayed S1, S4 is selected to switch the display. Thus, the display is put back to the display screen before the switching to eliminate the trouble of operation and vehicles are distributed with good efficiency.
MURATA KATSUJI
ABE KAZUYA
