Abstract: A server apparatus divides map data into a plurality of block data to add identification information to each block data, and sends each block data to a terminal apparatus. The terminal apparatus identifies data for each block data sent from the server apparatus and, when uncompleted block data is detected, sends retransmission request information, which requests only the uncompleted block data to be sent to the terminal apparatus, to the server apparatus.

Abstract: A communication navigation system that performs navigation, using map data stored in a map database site and current position data about navigation terminals, by transmitting the map data to the navigation terminals via a communication network such as the Internet, wherein the map data includes data units respectively corresponding to a plurality of display elements for display on a map, and the data units are given respective priority levels. The map database site is provided with a server for transmitting the data units via the communication network according to the respective priority levels. Each navigation terminal is provided with a transmitter/receiver for sequentially receiving the data units transmitted from the server, and a display subsystem for sequentially displaying the display elements respectively corresponding to the data units received by the transmitter/receiver, on the map.

Abstract: A communication navigation system includes a server that transmits route guidance information to terminal units via a communication network, and a transmitter/receiver, provided in each terminal unit, for transmitting specification data that specifies a type of necessary route guidance information, to the server via the communication network. The server transmits only the route guidance information of the type specified by the specification data, to the terminal unit.

Abstract: A communication navigation system includes a server that transmits items of route guidance information to terminal units via a communication network such as the Internet, a processing subsystem, provided in each terminal unit, for determining whether or not the items of route guidance information from the server are necessary, a display subsystem for performing guidance using only one or more items of route guidance information determined to be necessary by the processing subsystem, and a speech output subsystem.

Abstract: A server apparatus divides map data into a plurality of block data to add identification information to each block data, and sends each block data to a terminal apparatus. The terminal apparatus identifies data for each block data sent from the server apparatus and, when uncompleted block data is detected, sends retransmission request information, which requests only the uncompleted block data to be sent to the terminal apparatus, to the server apparatus.

Abstract: A communication navigation system includes a server SV that transmits route guidance information to terminal units T via the Internet IN, and a transmitter/receiver 15, provided in each terminal unit T, for transmitting specification data that specifies a type of necessary route guidance information, to the server SV via the Internet IN. The server SV transmits only the route guidance information of the type specified by the specification data, to the terminal unit T.

Abstract: A communication navigation system includes a server that transmits items of route guidance information to each of terminal units via the Internet, a processing subsystem, provided in each terminal unit, for determining whether or not the items of route guidance information from the server are necessary, a display subsystem for performing guidance using only one or more items of route guidance information determined to be necessary by the processing subsystem, and a speech output subsystem.

Abstract: A communication navigation system that performs navigation, using map data stored in a map database site and current position data about navigation terminals, by transmitting the map data to the navigation terminals via the Internet, wherein the map data includes data units respectively corresponding to a plurality of display elements for display on a map, and the data units are given respective priority levels. The map database site is provided with a server for transmitting the data units via the Internet according to the respective priority levels. Each navigation terminal is provided with a transmitter/receiver for sequentially receiving the data units transmitted from the server, and a display subsystem for sequentially displaying the display elements respectively corresponding to the data units received by the transmitter/receiver, on the map.