초록 ▼

A vehicle-mounted map acquisition apparatus 1 obtains maps A-D of different scales from a information center 30. Map A with a small scale covering a wide area is obtained at a starting point distant from a destination and is used to provide route guidance. As a vehicle approaches the destination, it

A vehicle-mounted map acquisition apparatus 1 obtains maps A-D of different scales from a information center 30. Map A with a small scale covering a wide area is obtained at a starting point distant from a destination and is used to provide route guidance. As a vehicle approaches the destination, it reaches a map acquisition point where map B with a larger scale is obtained. As the vehicle further approaches the destination, a map with a still larger scale is obtained. Map data with a scale suitable for each place along the way to the destination is obtained. As a large amount of data is not sent at once, sufficient map data can be obtained with a limited communication capability and a small capacity memory.

대표청구항 ▼

[ What is claimed is:] [1.] A map acquisition system including, connected via a communication medium, a center unit and a map acquisition unit in a vehicle for obtaining from the center unit map data covering areas to a travel destination, the system comprising:center-side map storage means installe

[ What is claimed is:] [1.] A map acquisition system including, connected via a communication medium, a center unit and a map acquisition unit in a vehicle for obtaining from the center unit map data covering areas to a travel destination, the system comprising:center-side map storage means installed in the center unit and storing map data with different scales;present-position detecting means for detecting the present position of the vehicle;destination setting means for setting the travel destination of the vehicle; anddeciding means for deciding, based on a detected present position, whether the vehicle has reached a map acquisition point individually set for said map data of each scale,wherein a map acquisition point where larger scale map data is obtained is set nearer to the destination so that the scale of map data obtained at a map acquisition point balances with the distance between this point and the destination, andthe center unit sends, based on a decision of said deciding means, the map acquisition unit map data with a scale corresponding to a map acquisition point where the vehicle has reached, whereinsaid present-position detecting means is included in the map acquisition unit andsaid deciding means is included in the center unit and decides, based on present position data sent from the map acquisition unit, whether a vehicle has reached the map acquisition point.