Abstract: Enabling a partial update of data for spot search and improvement of update operation efficiency. The data for spot search is constituted by (a) a plurality of spot search files RF-k having constitutional elements of POI data, (b) a menu display file MNF for displaying a search screen, and (c) an area table TBL. When periphery search is carried out, a mesh code where a spot on map designated by a user belongs is specified on the basis of the menu display file MNF and a search key containing the mesh code is generated. Further, the spot search file RF-k corresponding to the search key is specified on the basis of the area administration table TBL and extracts POI data corresponding to a facility, existing in a periphery of a spot which is designated by the user, is extracted out of the POI data contained in the spot search file RF-k.

Abstract: Enabling a partial update of data for spot search and improvement of update operation efficiency. The data for spot search is constituted by (a) a plurality of spot search files RF-k having constitutional elements of POI data, (b) a menu display file MNF for displaying a search screen, and (c) an area table TBL. When periphery search is carried out, a mesh code where a spot on map designated by a user belongs is specified on the basis of the menu display file MNF and a search key containing the mesh code is generated. Further, the spot search file RF-k corresponding to the search key is specified on the basis of the area administration table TBL and extracts POI data corresponding to a facility, existing in a periphery of a spot which is designated by the user, is extracted out of the POI data contained in the spot search file RF-k.

Abstract: Data recorded in a navigation apparatus can be partially updated, and, even when a difference is caused between the versions of spot searching data and map displaying data due to the partial updating, route setup is performed with certainty. When a spot to be a destination is designated by a user, a navigation apparatus 100 determines whether the version of a map file MPF recorded on a HD drive 105 matches the version of the spot searching file RF-k corresponding to the spot. If the versions of the two files MPF and RF-k are determined to match, a system control unit 115 sets a route, on the basis of the POI data of the spot contained in the spot searching file RF-k. If the versions are determined not to match, the system control unit 115 extracts the link ID corresponding to the road closest to the spot from the map file MPF, and sets a route, using the link ID.

Abstract: A bidirectional communication system includes a center unit and one or more terminal units connected to the center unit via a communication line. The center unit includes: program executing unit for executing one or more programs utilizing operation data in response to selection signals specifying a program to be executed and transmitting information associated with the programs to the terminal units via the communication line; control unit for controlling the program executing unit and the terminal units; and receiving unit for receiving the operation data from the terminal units and supplying the operation data to the program executing unit. The operation data being necessary for execution of the program.