A feature guidance information that provides guidance on a feature has a
data structure where a unique information representing a feature position
and a guidance position are associated with respective sub-areas so that
each sub-area includes at most one of the feature and the guidance
position to represent the feature or the guidance position. When it is
recognized that a vehicle reaches a position indicated by the unique mesh
information of the guidance position with respect to a current position
of the vehicle, guidance on the feature corresponding to the guidance
position is provided. Thus, an amount of information, load for
sending/receiving data and processing can be largely decreased compared
to that coordinates are used for representing the feature position and
the guidance position of the feature guidance information, thereby
providing smooth navigation.