Patent ID: 7839405

Claim:
A display control apparatus comprising: an image conversion unit configured to convert a three-dimensional spatial image constructed in a three-dimensional virtual space associated with a three-dimensional map plane into a first two-dimensional planar image by projecting said three-dimensional spatial image on a two-dimensional plane to result in said first two-dimensional planar image obtained if said three-dimensional spatial image is viewed from a first visual point at a first visual-line angle and for converting said three-dimensional spatial image into a second two-dimensional planar image by projecting said three-dimensional spatial image on said two-dimensional plane to result in said second two-dimensional planar image obtained if said three-dimensional spatial image is viewed from a second visual point at a second visual-line angle different from said first visual-line angle; a display unit configured to show one of said first and second two-dimensional planar images on a display screen of said display unit by switching said display screen from said first two-dimensional planar image to said second two-dimensional planar image or vice versa; a point specifying unit used for arbitrarily specifying a point, which is to be used as a point for specifying a visual-point position, on said display screen of said display unit; and a visual-point position setting unit configured to set the visual-point position of said second visual point so as to make a specified-point corresponding point existing on said three-dimensional spatial image as a point corresponding to a specified point face said specified point, which is arbitrarily specified through said point specifying unit as a point on said display screen of said display unit showing said first two-dimensional planar image, the three-dimensional map plane being a finite plane defined by a plurality of sides, and when the specified-point corresponding point lies outside the three-dimensional map plane, the specified point corresponding point is moved toward a side of the three-dimensional map plane that is closest to the specified-point corresponding point such that the specified-point corresponding point lies within the three-dimensional map plane.