Being the method of forming the geographical database which includes the data which expresses the plural road sections in navigation system null geographical dividing which

摘要

PROBLEM TO BE SOLVED: To provide an improved method for acquiring bearing data for performing guidance at intersections along a route by a navigation system. ;SOLUTION: A bearing of a road section indicates a direction in which the section proceeds from its terminal to the next. A primary bearing of a road section is acquired on a significant shape point located along the road section. The significant shape point is not necessarily a shape point closest to the terminal but a shape point located within or out of the range of a predetermined distance from the terminal. A secondary bearing is acquired on a plurality of road sections. The secondary bearing indicates an approximate direction along which the road section proceeding from the terminal follows. The secondary bearing is acquired through the use of the distance of a field of view. The distance of a field of view indicates an estimated distance of the field of view of a driver when the driver approaches an intersection based on the attribute of the road section.;COPYRIGHT: (C)2004,JPO