Road map data generation method, road map data update system, and road map data management device

摘要

A navigation device has a regional map data item for each of multiple regions, into which a nation is divided. A connection table is included in a regional map data item for a certain region and associates (i) a certain ID of a connection road in the certain region with a certain connection number. The connection road is connected with a paired connection road in an adjacent region. A connection table of a regional map data item for the adjacent region associates an ID of the paired connection road with the same connection number as the certain connection number. When the certain ID in the certain region is replaced with a different ID because of a road construction or the like, only the certain ID is replaced in the connection table with the certain connection number unchanged. This eliminates need of amending the connection table for the adjacent region.