JP2011215219A - Isolated road-extraction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an isolated road-extracting device which extracts an isolated road, which exists in road network data, with less memory consumption.SOLUTION: A grouping part 13 executes grouping processing for a road network which is read out from one mesh. Then, a flag information-giving part 14 executes flag information-giving processing which gives, to a group, connection-established flag information or isolated flag information, which are each flag information. In case that it is determined that the processing is executed to all the meshes, a control part 17 executes processing which combines groups generated in all the meshes. Then, in case that a plurality of groups exist, an isolated road-extracting part 16 extracts an isolated road which corresponds to the group to which the isolated flag information is given.

Description

  The present invention relates to a technique for extracting road network data corresponding to an isolated road from map data including road network data.

  Conventionally, a technique for updating a part of an electronic map used for a navigation device or the like is known. For example, the technique described in Patent Document 1 detects the presence or absence of an isolated state in which some roads are isolated from other roads when existing map data is updated based on update map data. Yes. Specifically, for example, when there is a deleted road, a search is performed for a route connecting one end and the other end of the deleted road, and the updated map data is in an isolated state when no route exists. Is detected.

JP 2008-249798 A

  However, in the technique described in Patent Document 1, when road data is deleted, only the isolated state of the road connected to the road is detected, and a part of the originally isolated road is deleted. In such a case, it may not be possible to detect that the road is in an isolated state. In the first place, the technique described in Patent Document 1 only determines whether there is a contradiction in the connection state of the road locally, and intends to extract an isolated road from the entire road network. Is not a technology.

When the technique described in Patent Document 1 is used to determine whether or not there is an isolated state in the entire road network, an ordinary route search algorithm requires a large amount of memory, which is not realistic. This is because, when searching for a route connecting one end and the other end of the deleted road, there are many candidate roads.
The present invention has been made to solve the above problems. An object of the present invention is to provide an isolated road extracting apparatus that can extract an isolated road existing in road network data with a small memory consumption.

In order to solve the above problems, the present invention provides road network data represented by nodes and links and boundary nodes existing at the boundaries of the mesh, which are divided by a plurality of meshes and managed in units of the meshes. A network data storage unit for storing set flag information, a data reading unit for reading road network data included in the mesh and flag information set in a boundary node, and nodes and links constituting the road network data Among them, there is a grouping unit that groups connected links and nodes, and a border node that is set with a main link corresponding to a main road or a connection confirmation flag information indicating that it is connected to the main road. When connection confirmation flag information is given to the included group A flag information giving unit for giving isolated flag information indicating the possibility of isolation to a group not including the main link and a group independently existing in a single mesh; and a group to which flag information is given The flag information assigned to the group is set in the included boundary node, and the flag information setting unit that stores the flag information in the network data storage unit corresponds to the group to which the isolated flag information is assigned. An isolated road extracting unit that extracts a road as an isolated road is provided.
Note that the above-described features do not enumerate all the features of the present invention, and a configuration (or method) including these as main parts can also be an invention.

  According to the present invention, an isolated road can be extracted from the entire road network data with less memory consumption.

The block diagram of an isolated road extraction apparatus. Explanatory drawing of a part of road network data. The flowchart of an isolated road extraction process. The flowchart of a grouping process. Explanatory drawing of a grouping process. The flowchart of a flag information provision process.

Hereinafter, examples embodying the present invention will be described.
As shown in FIG. 1, the isolated road extraction apparatus according to the present embodiment includes a network data storage unit 11, a data reading unit 12, a grouping unit 13, and a flag information adding unit configured by a hard disk, a flash memory, and the like. 14, a flag information setting unit 15, an isolated road extraction unit 16, and a control unit 17.

  The network data storage unit 11 stores road network data. As shown in FIG. 2, the road network data includes a link 23 representing a road 22 and a node 25 representing an intersection 24 on a map 21. The road network data is divided by a mesh 26 having a rectangular shape. The mesh is an area obtained by subdividing the map 21 corresponding to the entire area into predetermined sections composed of latitude and longitude. When the link 23 straddles the adjacent mesh 26, a boundary node 25 is given to the boundary point of the mesh 26. This boundary node 25 also constitutes road network data in the same manner as the node 25. Usually, map data is managed in mesh units. For example, when the map data is corrected / updated, it is executed for each mesh 26.

  Various attribute information is given to the link 23, the node 25, and the boundary node 25. The attribute information is information representing the characteristics of the route corresponding to the link or node, and is stored in the network data storage unit 11 in a state associated with the link or node. For example, the link cost, which is one of the link attribute information, generally represents the load applied to the user when passing the link. In addition, the link attribute information includes a unique ID number for identifying the link, a link length indicating the length of the link, latitude / longitude coordinates of nodes existing at the start and end of the link, altitude information, There are latitude / longitude coordinates, altitude information, route name, route type, etc.

The attribute information associated with the node includes a unique ID number for identifying the node, node coordinates, altitude information, a node name, a connection link ID describing a link ID of a link connected to the node, and the like. . The link and node altitude information may be information regarding the height relative to the height at the reference position, or may be above sea level.
Further, flag information is set as attribute information in the boundary node. This flag information includes connection confirmation flag information and isolated flag information. The connection confirmation flag information is set when the main link corresponding to the main road exists in the link directly or indirectly connected to the boundary node.

Here, the main road is an important route that connects main points and forms a skeleton of a network. For example, a highway and a national highway are applicable. In the present embodiment, a high-standard regional high-standard road that plays the role of a high-speed transportation system integrally with the main road and strengthens the regional structure may be included in the main road. This is because these regional high-standard roads are usually connected to expressways and national roads.
That is, the boundary node for which the connection confirmation flag information is set is information indicating that the node is not an isolated node connected to the main road.
In this embodiment, “isolated” refers to the state of a road corresponding to a road network that is not directly or indirectly connected to a main road.

  On the other hand, the isolated flag information is set when there is no main link corresponding to the main road in the link directly or indirectly connected to the boundary node. That is, the boundary node for which the isolated flag information is set is information indicating that the node is not connected to the main road and is an isolated node or a node that may be isolated.

The data reading unit 12 has a function of reading various data stored in the network data storage unit 11. For example, the data reading unit 12 reads road network data managed by the mesh and flag information set in the boundary node.
The grouping unit 13 has a function of grouping links and nodes that are directly or indirectly connected among the nodes and links constituting the road network data in the mesh as one group. For example, for a link and a node that are in a connection relationship, a unique ID is assigned to the group as attribute information so that it is possible to determine which link and node belong to one group.

  The flag information adding unit 14 determines whether or not the links constituting the group include a main link corresponding to the main road. If the main link is included, connection confirmation flag information is given to the group including the main link. This is because the road network constituting the group does not correspond to the isolated road defined in this embodiment. On the other hand, when the main link is not included, the isolated flag information is given to the group not including the main link. This is because a group composed only of a road network of narrow roads that does not include a main line link may correspond to an isolated road.

  Further, the flag information adding unit 14 is a case where the road node constituting the group includes a boundary node, and when the connection confirmation flag information is set to the boundary node, the flag information adding unit 14 Connection confirmation flag information is assigned. Since the border node for which the connection confirmation flag information is set is directly or indirectly connected to the trunk link corresponding to the trunk road in the adjacent mesh, the group including the border node is not isolated. This is because it can be determined.

  On the other hand, when the boundary node is not included in the road network constituting the group, the flag information adding unit 14 adds the isolated flag information to the group. This is because the group may be in an isolated state. Also, the flag information adding unit 14 adds isolated flag information to groups that exist independently in a single mesh. Even if a group that exists independently in a single mesh includes a trunk link, a road network that could only be grouped in a single mesh is isolated due to erroneous data input, etc. Because there is. Therefore, even if the flag information giving unit 14 once assigns the connection confirmation flag information to the group because the main link is included, the connection confirmation flag information is changed to the isolated flag information for the group satisfying this condition. It will be.

  The flag information setting unit 15 extracts the boundary node included in the group to which the flag information is assigned, and sets the same flag information as the flag information given to the group for the boundary node. The flag information setting unit 15 stores the flag information set in the boundary node in the network data storage unit 11. That is, the boundary node attribute information is updated.

  The isolated road extraction unit 16 corresponds to the group to which the isolated flag information is assigned when the grouping process is executed for all the meshes and the flag information is assigned to all the groups and the boundary nodes. The road is extracted as an isolated road. This is because a road corresponding to a road network that is not finally connected directly or indirectly to a main road can be recognized as an isolated road.

The control unit 17 has a function of controlling operations of the units 11 to 16 included in the isolated road extraction device based on a predetermined program recorded in a memory or the like.
The functions of the units 12 to 17 are actually realized by executing various programs stored in a memory or the like by a CPU (Central Processing Unit) (not shown) provided in the isolated road extraction device.

An isolated road extraction process for extracting an isolated road existing in the entire map data using the isolated road extracting apparatus configured as described above will be described.
As shown in FIG. 3, first, the data reading unit 12 reads road network data managed by one mesh among the road network data stored in the network data storage unit 11 (step S31).

Next, the grouping unit 13 performs a grouping process on the read road network (step S32). Specific grouping processing will be described later.
Next, the flag information adding unit 14 executes a flag information adding process for adding connection confirmation flag information or isolated flag information, which is flag information, to the group (step S33). Specific flag information addition processing will be described later.

  Next, the flag information setting unit 15 extracts all boundary nodes in the mesh, and sets flag information as attribute information of the boundary nodes (step S34). Specifically, the same flag information as the flag information given to the group to which the boundary node belongs is set as the attribute information of the boundary node. Even if the isolation flag information is set for the boundary node, if the connection confirmation flag information is assigned to the group to which the boundary node belongs, the flag information is changed from the isolation flag information to the connection determination flag information. Will be. Thereafter, the flag information setting unit 15 stores the boundary node in which the flag information is set in the network data storage unit 11.

  Next, the control unit 17 determines whether or not the grouping process and the flag information providing process have been executed for all meshes (step S35). When it is determined that processing has not been performed for all meshes, the control unit 17 performs grouping processing, flag information addition processing, and the like (steps S31 to S34) for meshes that have not been performed. On the other hand, when it determines with the process having been performed about all the meshes, the control part 17 performs the process which combines the group produced | generated in all the meshes (step S36). This process is a process in which the groups connected across the mesh are made one group. Specifically, for the groups of adjacent meshes connected by the boundary mesh, IDs that are attribute information of these groups are set to the same ID.

Next, the isolated road extraction unit 16 extracts an isolated road (step S37).
When there is only one group, in other words, when all the road network data is connected, the group to which the isolated flag information is added cannot exist, so the isolated road extraction unit 16 It is determined that there is no isolated road, and the process ends.
On the other hand, when there are a plurality of groups, the isolated road extraction unit 16 extracts a road corresponding to the group to which the isolated flag information is assigned.

  The road extracted by the isolated road extraction unit 16 is an isolated road that is not connected to the main road. In reality, there are few such isolated roads. Therefore, by checking the connection relation of the road network corresponding to the isolated road, it is possible to efficiently find the existence of road network maintenance omission or incorrect maintenance. Also, if there is no maintenance omission, etc., the road network data is obtained by determining the road that is connected from the isolated road to the main road and not maintained as a road network and preparing it as road network data. It becomes possible to enrich.

Next, an example of the grouping process (step S32) will be described with reference to FIGS.
As shown in FIG. 4, first, the grouping unit 13 selects an arbitrary link (step S41). In the example shown in FIG. 5, the link L2 is selected. Next, the grouping unit 13 sequentially searches and selects nodes and links that are directly or indirectly connected to the link (step S42). In the example shown in FIG. 5, nodes N1, N2 directly connected to the link L2 and links L1, L3-L6 indirectly connected are selected. Furthermore, the boundary nodes N5 to N9 to which the link is connected are also selected.

  Next, the grouping unit 13 assigns a group ID indicating one group to the links L1 to L6 and the nodes N1, N2, and N5 to N9 (step S43). The group ID may be given as attribute information of each link and node. In addition, a table in which group IDs are associated with grouped links and nodes may be created.

  Next, the grouping unit 13 determines whether or not links and nodes that are not grouped exist in the mesh (step S44). If all the links and nodes in the mesh are grouped, the grouping unit 13 ends the grouping process. On the other hand, when there are ungrouped links or nodes in the mesh, the grouping unit 13 selects an arbitrary link or node among the ungrouped links or nodes (step S45). Then, the grouping unit 13 performs a grouping process for the link or node.

  In the example shown in FIG. 5, links L7 and L8 exist as links that are not grouped. Therefore, the grouping unit 13 selects the link L7 and also selects the nodes N3 and N4 that are directly connected to the link L7. These links L7 and nodes N3 and N4 are grouped and the same group ID is assigned. Similarly, the grouping unit 13 selects the link L8 and the nodes N10 and N11 that are directly connected to the link L8. Then, these links L8 and nodes N10 and N11 are grouped, and the same group ID is given.

Next, an example of the flag information adding process (step S33) will be described.
As shown in FIG. 6, first, the flag information adding unit 14 pays attention to one group in the mesh, and refers to route type information that is attribute information of a link existing in the group. Then, it is determined whether or not there is a main link corresponding to a main road such as an expressway or a national road (step S61). When it is determined that a main link exists, the flag information adding unit 14 adds connection confirmation flag information to the group including the main link (step S62). On the other hand, if it is determined that there is no main link, the flag information adding unit 14 adds isolated flag information to a group that does not include the main link (step S63).

  Next, when the boundary node is included in the group to which the isolated flag information is added and the flag information is set in the boundary node, the flag information adding unit 14 sets the flag information to the group flag. The information is reflected (step S64). Specifically, when the connection confirmation flag information is set in at least one of the boundary nodes included in the group, the road network constituting the group is indirectly connected to the trunk line. It is connected to the link. Therefore, connection confirmation flag information is given to such a group by the flag information giving unit 14. On the other hand, when flag information is not set for all the boundary nodes included in the group or when isolated flag information is set, the flag information of the group remains unchanged as isolated flag information.

  Next, the flag information adding unit 14 determines whether or not the group is connected to another mesh (step S65). For example, when a boundary node is not included in a group, the group is configured only by a road network included in one mesh, in other words, a group that exists independently in a single mesh. It will be. In this case, the road network constituting the group is not connected to the main link. Even if it is connected to a main link, it is clear that it is an isolated network from other road networks. Therefore, when the group is not connected to another mesh, the flag information adding unit 14 adds isolated flag information (step S66).

  Next, the flag information assigning unit 14 determines whether or not flag information is assigned to all the groups in the mesh (step S67). When it is determined that no flag information is assigned to all groups, the flag information assigning unit 14 selects a group to which no flag information is assigned, and returns to step S61 to The process of giving flag information is executed. On the other hand, if it is determined that flag information has been assigned to all the groups included in the mesh, the control unit 17 ends the flag information addition process.

  According to the isolated road extracting apparatus of the present embodiment, it is possible to determine and extract an isolated road that is not connected to a highway or a national road, even a relatively wide range of roads that span a plurality of meshes. it can. Also, flag information is set as boundary node attribute information, and by using this flag information to grasp the isolated state for each mesh, if there is enough memory capacity to process one mesh, It is possible to realize processing for extracting roads that are isolated over the entire map data.

DESCRIPTION OF SYMBOLS 11 ... Network data memory | storage part 12 ... Data reading part 13 ... Grouping part 14 ... Flag information provision part 15 ... Flag information setting part 16 ... Isolated road extraction part

Claims (1)

Network data storage for storing road network data represented by nodes and links and flag information set at boundary nodes existing at the boundaries of the mesh, which are divided by a plurality of meshes and managed in units of the meshes And
A data reading unit for reading road network data included in the mesh and flag information set in a boundary node;
Among the nodes and links that constitute the road network data, a grouping unit that groups connected links and nodes;
The link confirmation flag information is given to a group that includes a border link corresponding to a trunk road or a boundary node in which connection decision flag information indicating connection to the trunk road is set, and the trunk link includes A flag information giving unit for giving isolated flag information indicating the possibility of isolation to a group that is not included and a group that exists independently in a single mesh;
A flag information setting unit that sets flag information given to the group in a boundary node included in the group to which flag information is given, and stores the flag information in the network data storage unit;
An isolated road extracting apparatus comprising: an isolated road extracting unit that extracts a road corresponding to the group to which the isolated flag information is assigned as an isolated road.