THREE-DIMENSIONAL MAP DISPLAY SYSTEM

摘要

A map database stores map data in multiple levels having different levels of details. In displaying a three-dimensional map, the map data having a higher level of details is used for a close view area near the viewpoint to a predetermined distance, and the map data having a lower level of details is used for a distant view area farther from the predetermined distance. The distant view area is first drawn by a perspective projection, and then, after clearing a depth buffer that stores depth information, the close view area is drawn, such that an undesirable hidden line removal process based on the depth information is not performed between the projected image in the distant view area and that in the close view area, thereby avoiding an unnatural phenomenon in which part of the close view image is hidden by the distant view image.