Abstract: In a route calculation process executed for each route calculation condition, an area including a link or an intersection that is target to compute a route calculation cost is determined; an area cost computing condition in which an element giving influence on the route calculation cost is associated with a computing condition for the route calculation cost for the link or the intersection including the element for each route calculation condition and for each area is acquired; and an adequate route from a departure point to a destination is determined for each route calculation condition using the route calculation cost computed based on the determined area and the area cost computing condition associated with the area.

Abstract: According to navigation systems and methods, when a detected current position has deviated from a guidance route, a navigation device transmits a reroute calculation condition to an information distribution center including the current position and the destination. Based on the reroute calculation condition, the information distribution center determines whether a distance from the current position to a closest adjacent link is equal to or shorter than a predetermined distance. When the distance from the current position to the closest adjacent link is longer than the predetermined distance, the information distribution center distributes to the navigation device reroute prohibition information including information regarding the adjacent link and a maximum waiting time. The maximum waiting time is a time that must elapse before the navigation device can again transmit the reroute calculation condition.

Abstract: According to navigation systems and methods, when a detected current position has deviated from a guidance route, a navigation device transmits a reroute calculation condition to an information distribution center including the current position and the destination, Based on the reroute calculation condition, the information distribution center determines whether a distance from the current position to a closest adjacent link is equal to or shorter than a predetermined distance. When the distance from the current position to the closest adjacent link is longer than the predetermined distance, the information distribution center distributes to the navigation device reroute prohibition information including information regarding the adjacent link and a maximum waiting time. The maximum waiting time is a time that must elapse before the navigation device can again transmit the reroute calculation condition.

Abstract: Navigation devices, methods, and programs store map data hierarchically with the map data of a hierarchy level being excluded. The devices, methods, and programs read the stored map data, perform a route search within each predetermined area on a departure point side and a destination side, and acquire a shortest cost route in a range overlapped in search areas. In a hierarchy level having a proximal higher hierarchy level of which the map data does not exist, the devices, methods, and programs expand the predetermined area into a search area in the proximal higher hierarchy level and acquire a first shortest cost route, and perform the route search in a higher hierarchy level to acquire a second shortest cost route. When the second shortest cost route's cost is smaller than the first shortest cost route's cost, the devices, methods, and programs update the cost of the shortest cost route.

Abstract: Navigation devices, methods, and programs store map data hierarchically with the map data of a hierarchy level being excluded. The devices, methods, and programs read the stored map data, perform a route search within each predetermined area on a departure point side and a destination side, and acquire a shortest cost route in a range overlapped in search areas. In a hierarchy level having a proximal higher hierarchy level of which the map data does not exist, the devices, methods, and programs expand the predetermined area into a search area in the proximal higher hierarchy level and acquire a first shortest cost route, and perform the route search in a higher hierarchy level to acquire a second shortest cost route. When the second shortest cost route's cost is smaller than the first shortest cost route's cost, the devices, methods, and programs update the cost of the shortest cost route.

Abstract: A navigation apparatus for searching for a route from a place of departure to a destination includes an information storage unit storing map data in a hierarchical structure, a route-searching unit for retrieving the map data from the information storage unit, searching for a route within a predetermined area on the departure side and on the destination side, and obtaining a route with the lowest cost in the range of overlapped search areas, and a control unit for controlling the search by the route-searching unit. The control unit updates the registered cost for the lowest cost route when the cost of the route of lowest cost obtained by searching up to a higher level within the hierarchy is smaller than that previously registered cost.