US Patent 7092817 Map information retrieving

Index data is provided for a retrieval method whose retrieval key does not contain positional information. From such index data, meshes are used to define an area (A1) based on the extent of a user's living area around a retrieval center (P) such as a current position, for example. A retrieval process extracts only index data corresponding to all institutions belonging to the meshes included in this area. The obtained index data is applicable to vicinities of the current position. Accordingly, it is possible to retrieve specific institutions near the current position without calculating distances using coordinate data for institutions included in detail information. As a result, the time for the retrieval process can be shortened.