| 摘要 |
PROBLEM TO BE SOLVED: To solve troubles in the case of converting the coordinates of a spherical surface into coordinates projected to a plane and plotting a road by linear interpolation between both the coordinates. SOLUTION: The map display device is provided with an information storage means 3 for storing map data constituted of two-dimensional coordinates, a display control means 4 having a coordinate conversion means 11 for converting the coordinates of the curved surface into the coordinates of a projected plane by allowing the coordinates of the map data to correspond to the coordinates of the curved surface and capable of reading out the map data from the means 3 and plotting a map and a display means 6 for displaying the map plotted by the means 4. In the case of reading out the map data from the means 3, converting the coordinates of the curved surface into the coordinates of the projected plane by the means 11 and plotting the map by linear interpolation between both the coordinates, the control means 4 sets up an interpolation point, converts the coordinates and the interpolation point into respective coordinates and executes linear interpolation, so that a trouble to be generated when a distance between the coordinates is long can be solved. |
