NAVIGATION DEVICE AND GUIDE ROUTE SEARCH METHOD
First Claim
1. A navigation device comprising:
- a map data storage unit configured to store map data, the map data divided into a plurality of hierarchical levels based on an amount of information about a road network, wherein an amount of information is greater at a lower level of the hierarchical levels than at a higher level of the hierarchical levels;
a first guide route search unit configured to search for a first guide route from a departure point to a destination by using the map data of the lowest level corresponding to an area surrounding the departure point and the destination, and using the map data of levels higher than the lowest level corresponding to an intermediate region outside the area surrounding the departure point and the destination;
a partial route extracting unit configured to extract a first partial route from the first guide route, wherein a difference between a straight-line distance and a distance measured between nodes at opposite ends of the first partial route is greater than a predetermined value;
a second guide route search unit configured to generate a second partial route by performing a route search between nodes at opposite ends of the first partial route using the map data including the lowest level; and
a guide route setting unit configured to set an eventual guide route representing a second guide route formed by replacing the first partial route of the first guide route with the second partial route.
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Abstract
A navigation device and a guide route search method prevents searching for a detour route, and shortens the time required for setting an eventual guide route. A first partial route is extracted from a first guide route found in accordance with map data divided into three hierarchical levels, based on information about a road network. The first guide route is the route from the current location to a destination. A second partial route is obtained by performing a route search between the nodes at opposite ends of the first partial route, based on the map data containing the lowest level. A second guide route is obtained by replacing the first partial route in the first guide route with the second partial route, and is set as the eventual guide route. Accordingly, a subsequent search operation is performed on a partial detour route in the first guide route, based on the map data containing the lowest level.
18 Citations
17 Claims
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1. A navigation device comprising:
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a map data storage unit configured to store map data, the map data divided into a plurality of hierarchical levels based on an amount of information about a road network, wherein an amount of information is greater at a lower level of the hierarchical levels than at a higher level of the hierarchical levels; a first guide route search unit configured to search for a first guide route from a departure point to a destination by using the map data of the lowest level corresponding to an area surrounding the departure point and the destination, and using the map data of levels higher than the lowest level corresponding to an intermediate region outside the area surrounding the departure point and the destination; a partial route extracting unit configured to extract a first partial route from the first guide route, wherein a difference between a straight-line distance and a distance measured between nodes at opposite ends of the first partial route is greater than a predetermined value; a second guide route search unit configured to generate a second partial route by performing a route search between nodes at opposite ends of the first partial route using the map data including the lowest level; and a guide route setting unit configured to set an eventual guide route representing a second guide route formed by replacing the first partial route of the first guide route with the second partial route. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A guide route search method in a navigation device, the navigation device including:
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a map data storage unit configured to store map data, the map data divided into a plurality of hierarchical levels based on an amount of information about a road network, wherein an amount of information is greater at a lower level of the hierarchical levels than at a higher level of the hierarchical levels; and a first guide route search unit configured to search for a first guide route from a departure point to a destination by using the map data of the lowest level corresponding to an area surrounding the departure point and the destination, and using the map data of levels higher than the lowest level corresponding to an intermediate region outside the area surrounding the departure point and the destination; the guide route search method comprising; extracting a first partial route from the first guide route, wherein a difference between a straight-line distance and a distance measured between nodes at opposite ends of the first partial route is greater than a predetermined value; generating a second partial route by performing a route search between nodes at opposite ends of the first partial route using the use of the map data including the lowest level; and setting an eventual guide route representing a second guide route formed by replacing the first partial route of the first guide route with the second partial route. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification