Navigation system having intersection routing using a road segment based database

摘要

A route searching system for a vehicle navigation system for navigating on a road network, for use when the road network database is organized in terms of road segments and the destination is a road intersection. The destination road segment for a particular guided route is selected so that the destination road segment is accessible from the destination intersection. This is of benefit when the destination road segment is one permitting only one way travel, and thereby avoids selecting as the destination road segment a one way road permitting travel only into the destination intersection. This allows selection of an optimum route without dictating that the route pass through a one way segment leading only into the destination intersection. Another improvement is destination road segment filtering, whereby if a destination road segment is chosen such that travel on it is zero distance, then that destination road segment is deleted from the guided route, and instead the end of the previous road segment on the guided route is indicated as being the destination. This eliminates unnecessary instructions being given to the driver when he arrives at the destination intersection.