AGGREGATION OF SEGMENT IN GEOGRAPHIC DATABASE AND METHOD FOR USING THE SAME FOR NAVIGATION APPLICATION

摘要

PROBLEM TO BE SOLVED: To improve the performance of a navigation system by allowing a part of an aggregation that is represented by one of data entities which represent the aggregation of road segments, to include reference to it. SOLUTION: Summary account records 522 and 523 are made to relatively approach an aggregation segment record 422 which refers to them and are maintained (physically and/or logically). The records 522 and 523 are included in a data layer that is the same as the aggregation segment record that refers to them. Further, the records 522 and 523 are included in a parcel 220 (7) that is the same as the aggregation segment 422 that refers to them. Plural aggregation segment records 422 can exist in each parcel that is upper than a layer 0 such as the parcel 220 (7) and each aggregation segment record 422 refers to the plural records 522 and 523.