1.  Field of the Invention
The present invention relates to an on-vehicle route guidance device and to a route guidance method which guide a vehicle driver by showing a route to a destination point. 
2.  Description of the Related Art
There is a per se known route guidance device (see Japanese Laid-Open Patent Publication No.  08-240438), in which a point of interest (POI) is set as the destination point by designating the name, address, the telephone number or the like of that POI and then the most suitable route to the destination point is searched for. 
However, with such a prior art type route guidance device, since a POI such as an institution or the like is set as the destination point and route searching is performed (this will hereinafter be termed route searching by POI), when traveling to a business area including a lot of buildings or the like, there is the problem in that searching for a POI which is a large company building or the like by setting it as the destination point can be difficult to perform.  Moreover, in a business zone or the like, it often may happen that there is no parking lot (parking space) at the POI which is set as the destination point, or that although there is such a parking lot it is full or is congested, so that it is necessary for the driver again to search for a parking lot in the area around the destination point.  Furthermore, even if the driver sets a parking lot in the area around a business zone or the like as the destination point, after he has parked the vehicle, it is necessary for him again to search for the actual place at which the institution which he desires to visit is located. 
It would be desirable to provide an on-vehicle route guidance device and a route guidance method which smoothly perform route guidance to a region (a zone) in which there are a plurality of POIs including at least one parking lot. 
An on-vehicle route guidance device according to the present invention comprises a map storage device which stores a road map, a zone storage device which stores information related to zones in which there are a plurality of POIs including at least one parking lot, a zone selection device which selects any zone from among the zones which are stored in the zone storage device, a route search device which sets a parking lot within a zone which has been selected by the zone selection device as a destination point, and which searches out a route to that parking lot based upon a road map which is stored in the map storage device and a route guidance device which guides the vehicle driver to that parking lot along the route which has been searched by the route search device. 
An on-vehicle route guidance device according to the present invention performs wireless communication with an information center.  The information center comprises a map storage device which stores a road map, a zone storage device which stores information related to zones in which there are a plurality of POIs including at least one parking lot and a route search device which sets a parking lot in a zone as a destination point and searches out a route to that parking lot based upon a road map which is stored in the map storage device.  This on-vehicle route guidance device comprises a zone selection device which selects any zone from among the zones which are stored in the zone storage device and a route guidance device which commands the information center to search for a route to a parking lot which has been selected by the zone selection device, and which guides the vehicle driver to that parking lot along a route which has been searched by the information center. 
A route guidance method according to the present invention comprises setting as a destination point a parking lot in a zone which has been selected from among these zones which are stored, based upon information stored in a memory related to zones in which there are a plurality of POIs including at least one parking lot, searching out a route to that parking lot which has been set as the destination point based upon a road map and guiding the driver to that parking lot based upon the route which has been searched. 
A route guidance method according to the present invention comprises selecting a zone selected from among the zones in which there are a plurality of POIs including at least one parking lot, commanding an information center to search for a route to the parking lot within the zone which has been selected, receiving a route which has been searched from the information center and guiding the vehicle driver to that parking lot based upon the route which has been received.