Aisin Aw Co., Ltd.

Yoichi Hayama

Hiroyoshi Masuda

Mamoru Kainuma

Akira Ishida

Hideki Nakashima

A map display apparatus for receiving and displaying map data transmitted from an information center. The map display apparatus includes a reporting device to report data-transmission expenses or data-transmission time required in receiving the map data from the information center; a determining device that allows a user to determine whether to receive the map data from the information center; and a requesting device to request the information center to transmit the map data upon a user's determination of receiving the map data.

Method for transmitting map data and map display apparatus and system

An information center generates packets of route guidance information, each corresponding to a prescribed road length of a recommended route. The information center may generate major guide point information and guidance information and transmit both to a vehicular apparatus. The vehicular apparatus provides guidance only for major guide points based on the received major guide point information if it cannot receive the guidance information. According to another aspect of the invention, if the end of a route segment which was the subject of the preceding route guidance information is on an expressway or toll road, guidance information for a preliminary route from that end to an escape position ahead on the expressway or toll road is first transmitted and then information for a remaining route, that is a segment of the recommended route having the prescribed road length minus the preliminary route, is then transmitted. If communication with the information center is lost, the vehicular apparatus performs guidance for the preliminary route to an interchange, for example, of the expressway using the preliminary route guidance information.

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Okazaki, Japan

Yoichi Hayama