JPH0498500A - Route searching method for navigation device - Google Patents

Abstract

PURPOSE:To arrive at the destination along the traffic flow by re-searching such route as can locate the destination on the left hand with respect to the running direction if inconvenience may take place because the destination is located on the right hand with respect to the running direction. CONSTITUTION:The candidates for a route to take to arrive at the destination departing from the origin which are inputted from an input device 8 are prepared using the road layer data stored in a map data storage device 9 and the route satisfying the prescribed conditions is decided by a data processing device 10. When it is judged from the positional relationships between the coordinates of the node constituting the roads and those of the destination, that the destination is located on the right hand with respect to the running direction, whether inconvenience may take place is judged, referring to an attribute data table B for the final road link of the route. If inconvenience may take place, such route as can locate the destination on the left hand with respect to the running direction is re-searched. Thus, it is possible to arrive at the destination along the traffic flow.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a route searching method for a navigation device which has a function of searching a route from a starting point to a destination point.

(Prior Art) A navigation device provides route guidance to a destination, and in recent years, in-vehicle navigation devices have been actively developed.

Generally, there are multiple routes between the starting point and the destination point, so a route with the shortest time or shortest distance to the destination point is created based on the road conditions of the map data stored in the storage device. A route search method has been devised.

(Problem to be Solved by the Invention) However, the shortest route is determined based on the road link distance between intersections stored as road data and the cumulative total of travel time, and it does not matter whether the destination point is located on the left or right side of the route. That has not been considered.

Therefore, as shown in FIG. 5, when the vehicle 1 travels along the search route 'fL1, the destination point 2 may exist on the right side of the last road link L1 of the search route in the direction of travel.

At this time, in the same figure, if road L1 is a narrow local road, there is no problem with the planned land, but if there is a median strip or a wide road with two or more lanes on each side, it is effectively the destination point. It cannot be said that the route up to 2 was created.

The present invention is intended to solve the above-mentioned problem, and when the destination point exists on the right side of the road link in the direction of travel determined at the end of the route search process, the destination point is located on the left side of the road link in the direction of travel. The purpose of this is to provide a method for searching a route so that the location of

(Means for Solving the Problem) According to the present invention, the above problem is solved by a route search means for searching a route from road data having a road attribute cheetah table;
Discrimination means for determining whether a problem occurs in the half where the destination point is located on the right side in the direction of travel, and #
: This is achieved by means of searching for a route such that the destination point is located on the left side of the traveling direction.

(Function) In the route search method of the navigation device of the present invention, a route is searched from road data having a road attribute data table, and it is determined whether a problem occurs when the destination point is located on the right side of the search route in the direction of travel. If the problem persists, the route is searched again so that the destination point is located on the left side in the direction of travel.

In addition, when determining whether the problem will occur if the destination point is located on the right side of the direction of travel when the destination point is input, if the problem does not occur, if the destination point is located on the right side of the vehicle's direction of travel. The route is searched based on the ground (2) data without considering whether the destination point is located on the right side or the left side in the direction of travel, and if a problem persists, the destination point is located on the left side of the final road in the direction of travel. Search for a route to the location.

(Example) Examples will be described below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a seven-stem configuration of a navigation device according to the present invention, and FIG.
The reason for this is a diagram showing an example of a road attribute data table included in road data, and FIG. 4 is a diagram for explaining the flow of route search processing.

1) In the g2 diagram, input the starting point and destination point using the input device 8. Similarly, the current position of the vehicle detected by the position detection device 7 based on the outputs of the mileage sensor 5 and the direction sensor 6 can also be input as the starting point.

The map data storage device 9Fi consists of a large-capacity memory that stores road maps, and this memory can be a CD-RO.
M etc. are used. The map data recorded in the above map data storage device includes a road layer consisting of road link data, difference point data, node data, etc., a background layer for outputting objects on the map to a display device 1) 4C, and municipalities. It consists of a character layer for outputting names, national road names, etc.

The road link data (road data), as shown in FIG. 3, is composed of cheetah tables A and B that provide attribute information of the corresponding road link. Attribute data table A is composed of data such as link distance, F9r9 time, one-way traffic flag, etc.
This is a data group used when creating and determining candidates for the shortest route or the shortest time-distance route.

Further, the attribute data table B shown in FIG. 3 is a data group used to determine whether or not a practical problem will occur when the destination point is located on the right side of the vehicle traveling direction.

FIG. 4 is a flowchart of the route searching method of the present invention.

The conventional route search process is realized by steps (1) to (5), and the process related to the present invention is realized by steps (61-33'').
d! This is achieved through the following steps.

A step-by-step explanation will be given below.

When you press the switch to start route searching, the second
The data processing device 10 shown starts a route search program (FIG. 4).

First, the coordinates on the map input as the destination point are stored in memory (step (1)). At this point, it is not yet certain whether the destination is located on the left or right side of the route.

Next, the coordinates on the map input as the starting point are stored in memory (step (2)).

Based on the coordinates of the starting point and the destination point, road layer data in a predetermined range on the map is read as appropriate from the map data storage device 9 into the memory built in the data processing device 10°. At this time, it is not necessary to read all data in the road attribute data table of the road link data to be read into the memory, and only the data group shown in FIG. 3A is sufficient from the viewpoint of saving processing time and memory (step (3)).

Next, using the road layer data, create several route candidates from the input starting point to the destination point, and after determining a route that satisfies the predetermined conditions, store the node data that makes up the route in memory. (Step (4)
-(5) ).

At this time, data on the intersection that is closest to the destination point and that is passed through when entering the road link searched as the last road on the route is also held.

With the above steps (1) to (51) in Figure 4, a route from the departure point to the destination point has been created, but as shown in Figure 5, destination point 2 is on the right side of the vehicle's direction of travel. However, if the road is narrow and parking is possible, or if it is easy to make a U-turn or cross the road, this is not a big problem in practical terms.

However, the development of road networks in recent years has been remarkable.
Even in rural areas, it is not uncommon to find roads with a width of four or more lanes, such as bypasses to bypass urban areas. On such roads, there is heavy traffic and some have median strips, making it virtually impossible to cross the road or make a U-turn. Additionally, due to the current road conditions, there are many roads in urban areas where parking and U-turns are not possible, even on roads that are not very wide.

In order to smoothly follow the flow of traffic and arrive at a destination, in Japan it is necessary to choose a route that places the destination on the left side of the vehicle's direction of travel. Therefore, the processing from step (6) onwards is required.

Step +1) - Once the route has been searched in (5), determine whether the destination point is located on the left or right side in the direction of road travel by comparing the positional relationship between the coordinates of the nodes that make up the road and the coordinates of the destination point. (Step (6)).

If the destination point is located on the left side of the route traveling direction, the route search process is now complete.

When the destination point is located on the right side of the route traveling direction, the attribute cheetah table of the road link that is the final road of the route is referred to, and the destination point is located on the road name @ and this practical problem is detected. It is determined whether or not this occurs (steps (7)-(6)).

If there is no practical problem, the route search process is now complete.

If the final road has a median strip or has 4 or more lanes,
If parking is prohibited and a U-turn is prohibited, the vehicle jumps to the next step and restricts the approach direction of the designated route link. That is, the one-way flag in the attribute data of the white road link is set, and it is assumed that it is not possible to enter the road link from the entry intersection 5 (see FIG. 1).

Furthermore, on the step side, the coordinates of the intersection are input as the coordinates of the starting point, and the route search is performed again.

As a result of this re-route search, as shown in Figure 1, the difference point 3
A route R2 is created that starts from the intersection 4 and enters the final road link L1, and the destination point is located on the left side in the direction of travel of the route.

Route R2 from intersection 5 created at this time to the destination point
is added to the route obtained by excluding the final road link from the route R1 obtained in the first route search stored in the memory.

Through the above processing, a route from the initially input starting point to the destination point will be searched.

However, in this embodiment, after the first route search is completed, it is determined whether the destination point is on the right side of the road link, and whether or not this will cause a problem.
When the destination point is input, refer to the attribute data table of the road link closest to the destination point to determine whether or not to correct a problem if the destination point is on the right side in the direction of travel (step (7) - al) ) may be performed.

In this case, if there is no problem even if the destination point is located on the right side of the route traveling direction, the route can be searched by performing the processes of steps (3) to (5).

If the problem is to be solved because the destination point is located on the right side of the route direction, set the one-way flag in the road attribute Cheetah Full of the final road before starting the route search process, and change the approach direction. By restricting this, a route is created such that the destination point is located on the left side of the direction of travel.

As is clear from the above explanation, when searching for a route from the starting point to the destination point, if a problem occurs because the destination point is located on the right side of the direction of travel, the destination point is located on the right side of the direction of travel. It becomes possible to search for routes, creating a pavilion where drivers follow the flow of traffic to reach their destination.

Similarly, in this example, the description was made in accordance with the traffic situation in Japan where people drive on the left, but the destination point position determination step (6
), by replacing the judgment of whether the destination point is on the right side of the direction of travel with the judgment of whether it is on the left side, it is possible to apply this route search method even in foreign countries where traffic is on the right side.

(Effects of the Invention) As described above, according to the route searching method of the present invention, if a problem occurs in the half where the destination point is located on the right side in the direction of travel, a route in which the destination point is located on the left side in the direction of travel is searched. It is possible for drivers to follow the flow of traffic to reach their destination.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the route searching method of the present invention, FIG. 2 is a block diagram of an in-vehicle navigation device, FIG. 3 is an explanatory diagram of the road attribute cheetah table included in the road take, and FIG. FIG. 4 is a flowchart of the route search process of the present invention, and FIG. 5 is a diagram for explaining problems with the conventional route search method. 1... Vehicle 2... Destination point 5.4...
・Intersection Ll...Final road link R1, R2・
...Search route Figure 1 Figure 5 Patent applicant Alvine Co., Ltd.

Claims (2)

[Claims] (1) In a route search method for a navigation device that has a function of searching for a route that satisfies predetermined conditions from a departure point to a destination point, a route that satisfies the conditions is searched from road data that includes a road attribute data table. a step of, when the destination point is located on the right side of the search route in the traveling direction, determining whether or not being located on the right side would cause a problem by referring to road attribute data; and if a problem occurs, determining the destination point; A route searching method comprising the step of searching the route again so that the route is located on the left side in the direction of travel of the route. (2) In the route search method of a navigation device that has the function of searching for a route that satisfies predetermined conditions from a departure point to a destination point, the final destination point is determined by referring to the road attribute data table included in the road data. If the destination point is located on the right side of the road in the direction of travel, the step of determining whether a problem will occur due to being located on the right side, and if the problem does not occur, determining whether the destination point is located on the right side of the vehicle in the direction of travel or to the left in the direction of travel. searching for a route that satisfies the above conditions from map data without considering whether the destination point is located on the final road; A route searching method comprising the step of searching for.