| 摘要 |
PROBLEM TO BE SOLVED: To perform suitable map display while suppressing wasteful data communication, by switching the range of map data previously acquired from a server with respect to a travelling direction, according to data transfer speed of radio communication, in a technology of off-board navigation. SOLUTION: A determining section 37 (determining means) determines whether the data transfer speed in a radio communication section 32 is high or low (determining processing). A range control section 38 (control means) sets (control processing) a different range (also called acquired range) of the map data to be acquired in response to the determination result of the data transfer speed in an acquiring section 35 or the server 5. COPYRIGHT: (C)2007,JPO&INPIT |
