3D MAP DISPLAY SYSTEM

A 3D map representing a feature that cannot be visually recognized such as an underground structure is displayed without a sense of discomfort. Among features stored in the map database, underground structures such as tunnels are classified into transmissive objects, and other features into non-transmissive objects. Then, the transmissive objects and the non-transmissive objects are projected individually so as to generate a transmissive object projection view and a non-transmissive object projection view. The transmissive object projection view thus obtained is superposed on the non-transmissive object projection view with adjusted transmittance. Making the transmissive objects to be transmissive and superposing them enables to realize a map that appears to the user as if a ground surface or features which blocked the transmissive objects are made to be transmissive whereby the transmissive objects become visible.