초록 ▼

A map data acquisition device is integrally mounted to an in-vehicle navigation device. Small scale map data is constantly carried in a database, while large scale, detailed map data is transmitted through communication from an information center serving as a base station. Using the small scale map

A map data acquisition device is integrally mounted to an in-vehicle navigation device. Small scale map data is constantly carried in a database, while large scale, detailed map data is transmitted through communication from an information center serving as a base station. Using the small scale map data, guidance is provided using the main roads. The traveling condition of the vehicle is detected and large scale map data is acquired when judged necessary based on the traveling conditions. For example, when the vehicle deviates from the established route, approaches a construction site indicated by traffic information, or nears the destination, detailed map data is acquired. Therefore, the appropriate detailed map is acquired at an appropriate point to cope with any changes in traveling conditions.

대표청구항 ▼

[ What is claimed is:] [1.] A map data distribution system including abase station and a transportable device linked with each other through communication means, wherein map data distributed from said base station is acquired from said transportable device,said transportable device comprising:travel

[ What is claimed is:] [1.] A map data distribution system including abase station and a transportable device linked with each other through communication means, wherein map data distributed from said base station is acquired from said transportable device,said transportable device comprising:traveling condition detection means for detecting a traveling condition of said transportable device; andrequest means for sending a request to said base station for detailed map data of an area surrounding or neighboring said transportable device when a detailed map of the area is determined to be required based on the detected traveling condition; whereinsaid base station responds to the request from said transportable device by supplying the detailed map data of the area indicated in the request.