Patent ID: 7912639

Claim:
A method for generating road map data in a center device for a navigation device in a vehicle, the road map data indicating a plurality of regions, each region including a connection road which is connected with a connection road included in an adjacent region, the method, comprising: generating a regional map data item for each region of the plurality of regions, each region being associated with position information; assigning each region with connection information which indicates a correspondence between a node ID and a link ID of the connection road in each region which is connected to the connection road in the adjacent region and a connection number, the connection number being identically assigned to the connection road in each region and the connection road in the adjacent region; and generating wide area road map data, which covers the plurality of regions while indicating road connections between adjacent regions by storing regional map data items of the plurality of regions in a storage medium such that a regional map data item for each region is provided with connection information while being associated with the position information; wherein when the road map data is being updated, in each region, the node ID or the link ID of the connection road connected with the connection road in the adjacent region is changed, the corresponding connection number is not changed.