SYSTEM AND METHOD FOR MAP DISPLAY

摘要

PROBLEM TO BE SOLVED: To solve a problem that a sharp elevation difference is generated in the boundary part between a two-dimensional bird's-eye view and a three- dimensional bird's-eye view in a map display system and that underground road data is not displayed. SOLUTION: A reference-elevation-value decision means obtains a reference elevation value on the basis of elevation data belonging to a prescribed region. On the basis of the reference elevation value, an elevation-data change means performs a processing operation in which the elevation of a plane region and that of a three-dimensional region can have continuity. Two-dimensional surface- of-the-earth road data and two-dimensional underground road data are differentiated so as to be stored in a two-dimensional road-data storage means. A three- dimensional road-data generation means generates three-dimensional surface-of- the-earth road data on the basis of the two-dimensional surface-of-the-earth road data and the elevation data, and it generates three-dimensional underground road data on the basis the two-dimensional underground road data and the elevation data.