Patent ID: 8115764

Claim:
A map display system having a function to display a three-dimensional map, the map display system comprising: at least one display device; at least one processor; and at least one memory device storing instructions which, when executed by the at least one processor, cause the at least one processor to operate with the at least one display device to: (a) categorize three-dimensional map data into: (i) scene graph data representing a data structure of the three-dimensional map using a tree structure having a plurality of hierarchical nodes, each of a plurality of objects included in the three-dimensional map being categorized into one of the hierarchical nodes; and (ii) rendering data for rendering each of the objects, the rendering data including a map information segment, a loading information segment, and a run-time information segment, each of the objects having: (A) a height above a ground surface; (B) a position; and (C) a size, the size being distinct from the height above the ground surface; (b) for a first one of the objects categorized in a first one of the hierarchical nodes and having a first size and a first position: (i) if the height of the first one of the objects exceeds a threshold value, change the categorization of the first one of the objects from the first one of the hierarchical nodes to a second different one of the hierarchical nodes, the second one of the hierarchical nodes being configured to include objects having heights exceeding the threshold value and objects having heights not exceeding the threshold value; (ii) if the height of the first one of the objects does not exceed the threshold value, do not change the categorization of the first one of the objects from the first one of the hierarchical nodes to the second one of the hierarchical nodes; and (iii) categorize point of interest data for the first one of the objects; (c) specify a display area by referring to the scene graph data; (d) read and display the rendering data and point of interest data in accordance with the specified display area; and (e) determine a level of detail based on a view point and a sight line in accordance with a distance from the view point to a ground surface of the three-dimensional map represented by a node.