JP3479237B2 - Traffic network route search method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer system for searching a route from a departure point to a destination point in a transportation network including transportation facilities under minimum cost conditions.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for route search in mobile terminals. In a complex transportation network, finding the optimum route is not easy. If the network becomes complicated, even a high-performance computer will increase the calculation time, making it virtually impossible to process.

Various techniques have been proposed in order to deal with such a situation in which calculation is substantially impossible. The label determination method, which is often used in computer-based shortest route search for transportation networks, requires a short processing time of the computer and can quickly obtain an answer. The label determination method will be briefly described below. The label determination method is sometimes called the Dijkstra method after the inventor of this method.

The label determination method will be described by taking a system represented by a network as shown in FIG. 1 as an example. Circles in the diagram corresponding to a specific point correspond to "nodes", and lines connecting the nodes correspond to routes between points and are called "links". Mathematically, the set of these nodes and links is called a graph,
Links with orientation are called directed graphs, and those without links are called undirected graphs. The example of FIG. 1 is an example of a directed graph. In such a system, the problem of finding the shortest route on the route from the node s at the starting point to the node t at the destination is the shortest path problem.

Now, the shortest path P from node s to node t
Be P = {s, i, j, ..., K, t}. At this time, with P as a boundary, P1 and P
When divided into two, the subsets P1 and P2 are also the shortest paths in each set. This is called the principle of optimality. The label determination method is an algorithm that mathematically finds the shortest path using this principle. That is, the label determination method starts with an empty set, assigns temporary labels to nodes, expands the shortest-path subset by finding each node that is the shortest path one by one, and finally labels all nodes. This is a method of determining the shortest path by fixing it to a permanent label. The following is an algorithm for programming on a computer.

The set of all nodes from the node s to the node t is V, the length d (j) of the shortest path from the node s to the node j, the set of nodes on the shortest path is S1, and its complement is S2. If (= V-S1), the shortest path is obtained by the following method. (1) As initialization, S1 ← 0 (empty set), S2 ← V d (s) ← 0, and d (i) ← ∞. Here, i is a node included in the complement set S2 of the shortest path node, and X ← Y represents that X is replaced with Y.

(2) If S1 = V, the calculation is completed. (3) If S1 ≠ V, select the shortest path length d (i) and set v ← i. Since the length d (v) is the shortest path from the node s to the node v, the node v is included in the node set S1 of the shortest path, and the node v is the complement set S2 of the node of the shortest path.
Remove from

(4) Link (outgoing link) leaving node v
Computes d ′ (i) ← d (v) + avi for all nodes i included in the complementary set S2 of the shortest path nodes, and if d (i)> d ′ (i) Let d (i) ← d '(i) and p (i) ← v. Here, avi is a length from the node v to the node i (link length), and d (i) and d ′ (i) are lengths of routes from the starting point s to i. D at this point
(I) is the shortest path length from the nodes in the set S1 of the shortest path nodes. There is a possibility that a shorter path exists in the complement set S2 of the shortest path node, but it will be obtained in the iterative calculation. (5) Return to step (2).

If p (i) obtained by the above method is traced backward from the final node t based on p (t),
The shortest path to the starting node s is found. For example, when the example of FIG. 1 is obtained by the above algorithm, d (1) = 0 d (2) = 50 d (3) = 70 d (4) = 65 d (5) = 85 p (2) = 1 p (3) = 2 p (4) = 2 p (5) = 3.

Since s = 1 and t = 5, node 3 (p (5) = 3) before node 5 and node 2 (p (3) before node 3
= 2), the node 2 is reached before the node 1 (p (2) = 1), that is, the starting point s. That is, the shortest path is 1 → 2 → 3 →
5 and its length is 85 (= d (5)). Also, node 1
From the path to the node 4 (1 → 2 → 4), the length d (4) is
After all it is the shortest path length.

As can be seen by actually simulating the path of FIG. 1 used in the above algorithm, node 3
It is not necessary to calculate the length d ′ (4) from the node 4 to the node 4.
That is, if the label determination method is used, the amount of calculation is much smaller than the shortest path calculation by total combination.

[0012]

The label determination method described in the prior art is characterized by high processing speed when a computer is used. In particular, when the starting point and the destination point are determined, the route that first reaches the destination point can be searched as the minimum cost route while sequentially finding the node having the minimum cost from the starting point by the label determination method. The target cost is specifically time or distance, and "moving time" or "moving distance" is evaluated.

In many navigation systems, various methods are used as means for solving problems on a computer, but when a route search is performed under the condition of minimum cost, the label determination method is basically used. For example, such a minimum cost route search includes a minimum cost route search using a railroad organization and a minimum cost route search system using an automobile.

In the general label determination method, the network data targeted for the route search are integrated into one, but it is necessary to use a plurality of divided network data due to the amount of data. is there. The present invention relates to a method for performing a route search by a label determination method using a plurality of divided network data.

When implementing a pedestrian navigation system or a car navigation system on a mobile terminal, there are many cases where the storage area is considerably limited due to the restriction of small size and light weight. Therefore, the map data is divided into a mesh structure because only the necessary map area is downloaded and used.

When map data of adjacent areas must be handled individually, it is necessary to establish a relationship with the adjacent mesh areas in order to perform a route search including data of the adjacent mesh areas using the label determination method. There is. Various methods can be considered to determine the relationship with the adjacent mesh area.
When considering route search in a small memory capacity such as mobile, it is desirable that the data be as small as possible.

An object of the present invention is to obtain a method for efficiently searching a route for mesh-shaped traffic network data by using a label determination method, and an efficient data storage method at that time. To aim.

[0018]

[Means for Solving the Problems] In order to solve the above problems, the traffic network is data divided into meshes, and using the data, a route from a departure point to a destination point, a point is a node, and a point is a point. In the traffic network route search method, which expresses a transportation network with links between them, and uses a computer to determine the label by the label determination method, such as travel time or travel distance under the shortest cost condition, the traffic divided into meshes is used. Network data is represented by a node that corresponds to a specific point, and the line that connects the nodes is represented by a link that is a route between points.If the link crosses the boundary of the mesh, set the node on the mesh partition side. , Numbering the nodes for each mesh, and regarding the nodes on the partition side, If the node changed to a permanent label is a node on the partition side in the route search processing by the label determination method, the adjacent mesh joining node of the node For the node shown as the data, the process for performing the route search process is added again.

The adjacent mesh joining node data is data describing which node of which mesh is the same node. This is one data item for one partition edge node. The adjacent mesh code is a code for expressing the above "which mesh". The adjacent mesh joining node data is a node number for expressing the above "which node".

In the above method, the relative mesh position can be used as the adjacent mesh code, or a specially managed number can be used as the node number on the partition side to reduce the data. .
For example, a number on a specific range or a specific serial number is used to notify that the node is on the partition side.

The present invention employs a method of managing data for each mesh of network data. This is one reason that mobile terminals with a small memory capacity can copy only a limited area. For example, it is difficult to read and use all the actual traffic network data of Japan even with a personal computer having a large memory capacity. In addition, searching large network data by random access will significantly slow down the search time, which has many advantages in actual route searching.

The general label determination method is premised on performing a route search on one network, but even if the network data is divided for each mesh, the label determination method is applied to perform the route search. be able to

The traffic network data divided into meshes is represented by "nodes" corresponding to specific points, and lines connecting the nodes are represented by "links" which are routes between the points. If the link crosses the boundary of the mesh, set a node on the partition side.

A mesh code number is assigned to each mesh. Nodes and links are numbered for each mesh. For this reason, since the partition edge nodes are numbered on both adjacent meshes, two numbers are given to one partition edge node. Each node is assumed to have the information of mesh code and node number. In the following description, the potential means a distance from the starting point or time.

The label here is defined as (l, p (v)) for each node. l is a link connecting nodes, v is the current target node, p (v)
Is the potential of path v. Note that the potential p
(V) is the cumulative cost of the route from the starting point (starting node) to the node v.

Step 1 (initial value setting) A special temporary label (*, 0) is attached to the starting node s, and temporary labels (Φ, ∞) are attached to the other nodes. The meaning of * means that no link comes in because it is a departure node. The meaning of Φ is that no link has reached the node yet. Such nodes are called unsearched. Step 2 (Process for Searching for Minimum Potential) Among the nodes with the provisional label, the node with the minimum potential is searched for and set as the minimum potential node v.
When the node v having this minimum potential is the target node, the process ends. If not, the node v having the smallest potential is obtained from the nodes of the temporary label, and the process proceeds to step 3. Step 3 (route search processing) δ-the end node connected by the link a from the node v
a, the cost of this is d (δ-a), and the potential of the node v already obtained from the starting point is p (v), the potential of the node δ-a is p (v) + d ( a) Assuming that the potential already set for the node δ-a is p (δa), p (v) + d
If (a) is smaller than p (δ-a), p (v) + d (a) is set as a new potential p (δ-a), and the temporary label is set as (a, p (δ-a)). After the above processing,
The temporary label of node v is a permanent label. After that, if the node v is a partition edge node, the process returns to step 4, and if not, the process returns to step 2 (minimum potential search process). Step 4 (adjacent mesh connection / route search processing) The node indicated by the adjacent mesh connection node of the node v is set to v, the route search processing is performed in the same manner as in step 3 above, and the label of the node v is set as a permanent label and the process returns to step 2. .

Step 5 (end processing) v is made into a permanent label, and the permanent label from v is traced in the reverse route and the route to the starting point is output in the required format.

In the present invention, since the traffic network data is managed for each mesh, it is necessary to have information about which mesh side node is connected to which mesh side node. The adjacent mesh connection node data is given in advance.

The traffic network data used in the present invention is divided into a plurality of meshes. As an example of such divided data, JIS-X0410-1976 "region mesh code" will be described. In the JIS "Regional mesh code", Japan is divided into meshes divided by longitude and latitude, and a code is assigned to each mesh.

The code indicating the mesh section is a combination of a two-digit number indicating the frequency obtained by multiplying the southernmost latitude of the section by 1.5 and a two-digit number obtained by subtracting 100 from the number indicating the westernmost longitude in this order. Represented by a 4-digit number. For example, the code for the section where the southernmost latitude of the section is 36 degrees north latitude and the westmost longitude is 142 degrees east longitude is 5442.

One of the above meshes (primary area section)
Is further divided into 8 equal parts vertically and horizontally, and subdivided into 64 secondary meshes (secondary area divisions). The code for the secondary mesh is 8 in the meridian direction and the latitudinal direction.
Numbers from 0 to 7 are assigned to each of the sections obtained by dividing it in the meridian direction from the south and from the west in the latitudinal direction, and these numbers are combined in the order of the meridional direction and the latitudinal direction. Use a 2-digit number. One side is about 10km.

Further, the secondary mesh is divided into 10 parts in each of the vertical and horizontal directions to form 100 third meshes (third area divisions). The area of this mesh is about 1 km square. In car navigation systems, etc., the secondary mesh is often used. The secondary mesh code is the primary area and the secondary
It is a combination of numbers that indicate the next area division.

Normally, a personal computer handles data in byte units with 8 bits as one byte. Further, in order to mask a bit data and extract a necessary portion, the data is stored in 2 bytes or 4 bytes because an operation is performed by substituting it in an integer variable. The adjacent mesh connection node data is data that describes which node of which mesh is the same node. This is one data item for one partition edge node. The adjacent mesh code is a code for expressing the above "which mesh". The adjacent mesh joining node data is a node number for expressing the above "which node". Here, the adjacent mesh code can be stored at a relative position of 4 bits and the adjacent mesh joining node data can be stored at 12 bits for one partition side node. If the adjacent mesh joining node data is 12 bits, it can handle up to 4096 partition side nodes.

For example, even if there are relatively large meshes of 1 mesh 10 km square and there are roads at intervals of 30 m, since there are about 300 meshes per division side, the sum of all four mesh sides will be 1200 meshes, which is sufficient. is there. By the way, since the average of each secondary mesh is about 10km, it can be said that 2-byte data is sufficient.

Of the secondary meshes classified by JIS, the one with the largest number of nodes is 523667 near Nagoya. The mesh has about 18500 nodes and 61300 links. Also, the number of partition edge nodes is 5
There are 532 in 23657. Therefore, it can be said that 10 bits (up to 1024) can secure only the number of partition side nodes, but 12 bits allows 4096 nodes to be secured.

The area for storing the adjacent mesh connection node data is as shown in FIG. 2 (the number of nodes to be stored).
X (one adjacent mesh junction node data capacity). A comparison will be made for each and a comprehensive comparison. In a general data structure, if all the nodes have the adjacent mesh joining node data, the nodes other than the partition side nodes can secure a completely unnecessary area. If this unnecessary area is omitted, data can be stored efficiently.

That is, an average of n
If there are nodes and the network is almost like a grid, the number of nodes in the mesh is n ² . At that time, the number of partition edge nodes is 4n on four sides, so n ²
-4n means that a meaningless area was secured. Since there are about 18,000 nodes per mesh in the secondary mesh in the city center and about 500 partition side nodes, 97% of the nodes can secure a meaningless area.

Next, the capacity of one adjacent mesh junction node data will be described. A general road network structure has adjacent mesh codes and node numbers of adjacent meshes. If each node has a mesh code and a node number, the capacity required for adjacent mesh joining node data is (number of nodes) × (number of mesh code bytes +
Node number byte count). In case of JIS, the mesh code is a 6-digit number as specified in JIS-X0410-1976, so at least 4 bytes are required. However, this is an integer representation, and 6 bytes are required for character representation.

For example, when there are 18000 nodes as described above, when the mesh code is a 4-byte integer and the node number is a 2-byte integer, a capacity of 18000 × (4 + 2) = 108000 bytes is required.

In the method used in the present invention, the mesh number is stored at a relative position of 4 bits, and the node number need only be the node number of the partition side node.
As described with respect to the secondary mesh divided by, 12 bits are sufficient. Therefore, the adjacent mesh joining node data requires 16 bits, that is, 2 bytes, for one partition edge node. Moreover, since these data need only be owned by the partition side nodes, if the number of partition side node data is 500, 500 × 2 = 1000 bytes will suffice, and compression of 100 times or more will be possible.

From the above, the adjoining mesh joining node data for one node used to be at least 6 bytes, but now it becomes 2 bytes, and by making this data only in the partition side nodes, FIG. As shown, the compression is realized in the vertical and horizontal directions.

The adjacent mesh joining node data will be described using a simple network. In the example shown in FIG. 4, the mesh 533934 has six partition side nodes and two nodes other than the partition side nodes. There are 9 meshes including the meshes around it. For example, the adjacent mesh joining node data of node 126 of mesh 533934 is mesh 5
It is the node 374 of 33933.

The adjacent mesh codes can be easily calculated in the upper, lower, left, and right adjacent mesh codes by the JIS numbering method. For example, the right of 533936 is 5339
37, lower left is 533925.

An example of the method for storing the adjacent mesh connection node data will be described. 4 for one edge node
As the bit data, the data in the mesh adjacent to the relative mesh position is stored as shown in FIG.

It suffices that the adjacent mesh code can express where it is located above, below, to the left or to the right as viewed from its own mesh. Two specific examples are shown as a method of expressing the relative position.

In the example shown in FIG. 6, the 4 bits of FIG. 5 are assigned to the upper, lower, left and right bits from the front. For example, in the case of the upper right corner, the binary code is 1001, so the adjacent mesh code is 9. The bottom is 0100, so it will be 4.

The example shown in FIG. 7 is a method in which numbers are simply assigned from the lower left. If the map data is made so that it does not connect from corner to corner of the mesh, upper right, upper left,
Since it is not necessary to express the lower right and lower left, it is 4
Only 3 bits are needed to express the direction.

The adjacent mesh joining node data is the number of the same overlapping partition edge node attached to the adjacent mesh. In general, node attributes are rarely given to the node number itself, and in many cases, a node attribute storage area is used to secure a data area for classification. Having the node number itself means that the attribute can be known just by looking at the node number.

The node number itself can be given an attribute as to whether it is a partition side node, and the adjacent mesh joining node data can be efficiently stored by the numbering method. Specifically, the nodes from the number to the number are the partition side nodes.

The nodes are classified into partition edge nodes and other nodes, and the partition edge nodes are collected so that they can be managed by serial numbers. The simplest method is to collect the node of the partition side node at the front and assign the node number from 0 so that it can be managed by serial number, and the nodes other than the partition side node are connected to the end of the node and numbered. Is the way. Of course, the data of the partition edge node may be collected behind. In any case, it suffices if the data of the partition side nodes can be managed by serial numbers.

When the mesh code of each part of the divided map data is regularly given, the adjacent meshes are calculated.

[0052]

BEST MODE FOR CARRYING OUT THE INVENTION The method of the present invention will be described by taking a road network as shown in FIG. 8 as an example. Mesh 5339
The node 5 of 35 is set as the starting point and the node 3 of the mesh 533934 is set as the destination. Mesh 53 as a representation of node number
The node 5 of 3935 is expressed as 533935.

Step 1: Departure point 533935 (*, 0) Step 2: Set v to be the departure point 533935. Step 3: Search v. Compute the potential of the end node of the link leaving v. The end point nodes of 533935 are 533935, 533935, 533935, 533935. Since all of these end nodes have not been searched yet, the potential of the end node is the sum of the costs from the potential 0 + v of v to each end node. Therefore, the potential of each end node is 533935 (533935,6), 533935 (53
3935, 7), 533935 (533935, 5), 533935 (53
3935, 5). Temporary labels are attached to these end nodes. The starting point of v is potential 0 and it is a permanent label, and it goes to step 2.

Permanent label list: {533935 (*,
0)} Temporary label list: {533935 (533935, 5), 533935
(533935, 5), 533935 (533935,6), 533935
(533935, 7)}

Step 2: A temporary label having a minimum potential is searched for. 533935 (533935, 5)
Is the smallest with potential 5.

Step 3: Search for v, 533935. The links from 533935 are 5339352, 533935
3,5339354. Since the end point node of 5339352 has not been searched, the potential is 5 + 8 = 13. Therefore, 533935 (533935, 13) is registered with a temporary label. Similarly, the end point node of 5339354 is 533935 (533935
, 8) is registered with the temporary label v. The potential of the end point node of 5339353 has already been confirmed with a lower potentia than this time, so the temporary label will not be registered. 533935
Goes to step 2 as a permanent label with potential 5.

Permanent label list: {533935 (*, 0),
533935 (533935,5)} Temporary label list: {533935 (533935, 5), 533935
(533935,6), 533935 (533935, 7), 533935
(533935, 8), 533935 (533935, 13)} Step 2: 533935 (533935, 5) has the smallest potential in the temporary label. Set v to 533935 and go to step 3. Step 3: Only the 53393514 link is output from 533935, and since the end point of the link has been confirmed with the potential of 0, the temporary label is not registered. 533935, which is v, has a potential of 5 and is a permanent label. Here, since 533935 is the partition edge node, the process proceeds to step 4. Step 4: The adjacent mesh joining node data of 533935 is 533934. A node v is searched with 533934 as v. The link from 533934 is 5339344. Five
Since the end point node 533934 of 339344 has not been searched, the potential becomes 5 + 5 = 10. Therefore 533934
(533934, 10) is registered with a temporary label. 533934
Goes to step 2 as a permanent label with potential 5. Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5)} Temporary label list: {533935 (533935,6), 533935
(533935, 7), 533935 (533935, 8), 533934
(533934,10), 533935 (533935,13)} Step 2: Set v to 533935 and go to Step 3. Step 3: The label after searching v as 533935 is as follows. The temporary label of 533935 is now 533935
Although it was registered with the potential 13 as (533935, 13), the potential is smaller when it goes through 533935 according to the formula of * 1, so the temporary label is 533935.
It is rewritten as (533935, 10). Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5), 533935 (533935,6)} Temporary label list: {533935 (533935, 7), 533935
(533935, 8), 533934 (533934,10), 533935
(533935, 10)} Step 2: Set v to 533935 and go to Step 3. Step 3: The label after searching v as 533935 is as follows. Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5), 533935 (533935,6), 533935 (533935
, 7)} Temporary label list {533935 (533935, 8),
533934 (533934,10), 533935 (533935, 1
0), 533935 (533935, 13), 533935 (533935
, 14)} Step 2: Set v to 533935 and go to Step 3. Step 3: The label after searching v as 533935 is as follows. Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5), 533935 (533935,6), 533935 (533935
, 7), 533935 (533935, 8)} Temporary label list: {533934 (533934,10), 533935
(533935, 10), 533935 (533935, 13), 5339
35 (533935, 14)} Step 4: Search v for 533935 adjacent mesh junction node data 533934. Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5), 533935 (533935,6), 533935 (533935
, 7), 533935 (533935, 8), 533934 (533935
, 8)} Temporary label list: {533934 (533934,10), 533935
(533935, 10), 533935 (533935, 13), 5339
35 (533935, 14), 533934 (533934, 15)} Step 2: Set v to 533934 and go to Step 3. Step 3: The label after searching v as 533934 is as follows. Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5), 533935 (533935,6), 533935 (533935
, 7), 533935 (533935, 8), 533934 (533935
, 8), 533934 (533934,10)} Temporary label list: {533935 (533935, 10), 533935
(533935, 13), 533935 (533935, 14), 5339
34 (533934, 15), 533934 (533934, 18), 53
3934 (533934, 21)} Step 2: Set v to 533935 and go to Step 3. Step 3: The label after searching v as 533935 is as follows. Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5), 533935 (533935,6), 533935 (533935
, 7), 533935 (533935, 8), 533934 (533935
, 8), 533934 (533934,10), 533935 (533935)
, 10)} Temporary label list: {533935 (533935, 13), 533935
(533935, 14), 533934 (533934, 15), 5339
34 (533934, 18), 533934 (533934, 21)} Step 2: Set v to 533935 and go to Step 3. Step 3: The label after searching v as 533935 is as follows. Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5), 533935 (533935,6), 533935 (533935
, 7), 533935 (533935, 8), 533934 (533935
, 8), 533934 (533934,10), 533935 (533935)
, 10), 533935 (533935, 13)} Temporary label list: {533935 (533935, 14), 533934
(533934, 15), 533934 (533934, 18), 5339
34 (533934, 21)} Step 4: Search v for adjacent mesh junction node data 533934 of v 533935. Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5), 533935 (533935,6), 533935 (533935
, 7), 533935 (533935, 8), 533934 (533935
, 8), 533934 (533934,10), 533935 (533935)
, 10), 533935 (533935, 13), 533934 (5339
35, 13)} Temporary label list: {533935 (533935, 14), 533934
(533934, 15), 533934 (533934, 18), 5339
34 (533934, 20), 533934 (533934, 21)} Step 2: Set v to 533935 and go to Step 3. Step 3: The label after searching v as 533935 is as follows. Permanent label list: {533935 (*, 0), 533935 (53
3935,5), 533935 (533935,5), 533934 (5339
35,5), 533935 (533935,6), 533935 (533935
, 7), 533935 (533935, 8), 533934 (533935
, 8), 533934 (533934,10), 533935 (533935)
, 10), 533935 (533935, 13), 533935 (5339
35, 14)} Temporary label list: {533934 (533934, 15), 533934
(533934, 18), 533934 (533934, 21)} Step 2: The node having the smallest potential among the nodes of the temporary label is the target node 533934, and the process ends.

The minimum cost route may connect the ingress node of the permanent label from the destination. Label 533934 (533934
, 15), 533934 forms the minimum cost coming from 533934, and the total route cost is 15. Then 533934 permanent label 533934 (533935
, 8), 533934 is the minimum cost route that comes in from 533935. The label of 533935 is 533935 (53
Since it is 3935, 5), it will come in from 533935. Therefore, the minimum cost route is 533934 ← 533934 ←
533935 ← 533935.

[0059]

The general label determination method is premised on performing a route search on one network, but according to the method of the present invention, even if the network data is divided for each mesh, the label is Since the definite method can be applied to perform the route search, it is possible to download the network data only for the area required for the mobile terminal and to perform the route search even with a terminal device having a small memory capacity.

Further, according to the present invention, in the storage of the adjacent mesh connection node data, there is an effect that the data can be stored with a small data capacity, and the route search can be performed at a high speed even if the data becomes large.

[Brief description of drawings]

FIG. 1 is a network diagram for explaining a method of obtaining an optimum solution using a label determination method.

FIG. 2 is an explanatory diagram of a data area that stores adjacent mesh joining node data.

FIG. 3 is an explanatory diagram of a data area for storing adjacent mesh joining node data.

FIG. 4 is an explanatory diagram of adjacent mesh joining node data.

FIG. 5 is an explanatory diagram of a data structure according to the present invention.

FIG. 6 is an explanatory diagram of an adjacent mesh code.

FIG. 7 is an explanatory diagram of an adjacent mesh code.

FIG. 8 is an explanatory diagram of a road network.

Continuation of the front page (56) Reference JP-A-10-239079 (JP, A) JP-A-11-174953 (JP, A) JP-A-8-136276 (JP, A) JP-A-8-122089 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01C 21/00 G08G 1/0969 G09B 29/10

Claims (9)

(57) [Claims] 1. A traffic network is data that is divided into meshes, and a route from a starting point to a destination point is expressed by using the data, the traffic network is expressed by using points as nodes and points as links, and a computer is used. In the transportation network route search method that searches under the shortest cost condition using traveling time or traveling distance as cost by the label determination method, the transportation network data divided into meshes is the node corresponding to a specific point, The line connecting the nodes is represented by a link that is a route between points, and when the link crosses the boundary of the mesh, set the node on the mesh partition side, assign a number to the node for each mesh, For the nodes on the partition side, the numbers assigned to the nodes on the partition side in the adjacent mesh When the node that has been changed to a permanent label is a node on the partition side in the route search process by the label determination method, the route is re-established for the node indicated by the adjacent mesh joint node data of the node. A transportation network route search method characterized in that a process for performing a search process is added. 2. The traffic network route search method according to claim 1, wherein a relative mesh position is used as the adjacent mesh code. 3. A specially managed serial number is used as a node number on the partition side.
Method of route search for transportation network described. 4. A traffic network is data that is divided into meshes, and a route from a starting point to a destination point is expressed by using the data, the transportation network is expressed by using points as nodes and points as links, and a computer is used. In the traffic network route search system that searches under the shortest cost condition using the travel time or travel distance as the cost by the label determination method, the traffic network data divided into meshes is the node corresponding to a specific point, The line connecting the nodes is represented by a link that is a route between points, and when the link crosses the boundary of the mesh, set the node on the mesh partition side, assign a number to the node for each mesh, The nodes on the partition side are assigned to the nodes on the partition side in the adjacent mesh. If the node that has the adjacent mesh connection data that is a number is a node on the partition edge in the route search process by the label determination method, the node indicated by the adjacent mesh connection node data of the node is again A transportation network route search system characterized by adding processing means for performing route search processing. 5. The traffic network route search system according to claim 4, wherein a relative mesh position is used as the adjacent mesh code. 6. A specially managed serial number is used as a node number on the partition side.
The described transportation network route search system. 7. A transportation network is data divided into meshes, and a route from a starting point to a destination point is expressed using the data, the transportation network is expressed by using points as nodes and points as links, and a computer is used. By using the travel time or travel distance as a cost by the label determination method, the traffic network route search is performed under the shortest cost condition, and the traffic network data divided into meshes is the node corresponding to a specific point. The line connecting the nodes is represented by a link that is a route between points, and when the link crosses the boundary of the mesh, the node is set on the mesh partition side, and a number is assigned to the node for each mesh. For the node on the partition side, the number given to the node on the partition side in the adjacent mesh In the route search process by the label determination method, when the node that has been changed to a permanent label is a node on the partition side, the route search is performed again for the node indicated by the adjacent mesh joint node data of the node. A recording medium for a computer in which a program for adding and executing a processing procedure for processing is recorded. 8. A computer-readable recording medium according to claim 7, wherein a relative mesh position is used as the adjacent mesh code. 9. A specially managed serial number is used as a node number on the partition side.
The recording medium for a computer described.