ROAD MAP DISPLAY DEVICE AND RECORDING MEDIUM USED IN THE DEVICE

摘要

A road map display device which comprises a map information storing device for storing road map data on two-dimension coordinates, and a detection device for detecting the current position and the advancing direction of the own vehicle, and which obtains the two-dimension coordinates of road map data from the map information storing device based on the current position and the advancing direction of the own vehicle detected by the detection device, and draws as a plan view the two-dimension coordinates on a display screen, wherein trapezoid conversion parameters are set based on a conversion formula that shortens the upper side of specified-quadrangular two-dimension coordinates relative to the lower side thereof and converts the two-dimension coordinates of the road map data into trapezoidal coordinates for perspective displaying, road map data included in inverse trapezoidal coordinates defined based on the inverse conversion formula of the above conversion formula are read from the map information storing device for introduction into trapezoidal coordinates specified by the trapezoid conversion parameters, and the introduced road map data are drawn as a perspective view.