JP5776403B2 - Region search method, region search program, and information processing apparatus - Google Patents

Description

  The present invention relates to a region search method and the like.

  Conventionally, data management using an index is used in order to retrieve data meeting a condition from a large amount of data existing in a space at high speed. Data management methods using indexes include a method using B-Tree (B-tree) used when searching one-dimensional data and an R-Tree (R-tree) used when searching multidimensional data. There is a method using.

  For example, data management using an R-tree will be described with reference to FIG. FIG. 25 is a diagram illustrating an example of data managed by the R-tree and a rectangular area. As shown in FIG. 25, R0 is a rectangular area including all the rectangular areas of the child nodes R1 to R4, and R1 is a rectangular area including all of the rectangular areas R5 to R8. Further, R5 to R11 in the lowermost stage are leaf nodes, which are rectangular areas including data therein. That is, R0 is index information of R1, and R1 is index information of R5.

  In order to search for data that meets the conditions, when searching for the corresponding range using this index information (referred to as “range search”), the search range from the four child nodes R1 to R4 of R0 that is the root node. Select the nodes that overlap. A node having overlapping portions recursively selects a node having overlapping search ranges, and finally selects data within the search range from leaf nodes.

  As a method of such range search, the current position is hierarchized from the coordinate information on the hierarchized area such that a plurality of narrow areas are included in a wide area and the current position measured by the GPS device. Patent Document 1 discloses a technique for performing a search determination as to which region belongs.

JP 2000-249564 A

  However, the conventional range search using an index has a problem of requiring a search time. That is, in the data management method using the R-tree, every time a search operation is executed, the search is started from the root node, so that the number of times of logN order search is always required, and search time is required.

  Even when a range search is performed using coordinate information related to the hierarchized area, search determination related to the current position to be measured is started in order from a wide area every time the current position is measured. There is no change in taking time.

  It is an object of the disclosed technique to speed up the search time for a range search using an index.

  In one aspect, the region search method uses index tree that is index information used when searching for a region, and includes index information for managing the region together with region information including a plurality of regions, in a tree structure. When an area including a predetermined position is searched and an area including the position can be searched, the overlapping of the areas that can be searched based on the storage unit that stores information on the overlapping areas that overlap the areas for each of the plurality of areas This includes retrieving an area including the position from the area and outputting information on the retrieved area.

  According to one aspect of the region search method disclosed in the present application, it is possible to speed up the search time for a range search using an index.

FIG. 1 is a functional block diagram illustrating the configuration of the area search server according to the first embodiment. FIG. 2 is a diagram illustrating an example of information stored in the region index DB. FIG. 3 is a diagram illustrating an example of root node information stored in the region index DB. FIG. 4 is a diagram illustrating an example of intermediate node information stored in the region index DB. FIG. 5 is a diagram illustrating an example of leaf node information stored in the region index DB. FIG. 6 is a diagram illustrating an example of the data structure of the area data DB. FIG. 7 is a diagram showing an example of the contents of the area search request. FIG. 8 is a diagram illustrating an example of the contents of the region search response. FIG. 9A is a flowchart illustrating a procedure of request reception processing related to search. FIG. 9B is a flowchart illustrating the search processing procedure according to the first embodiment. FIG. 10 is a flowchart (1) illustrating the procedure of the area data adding process according to the first embodiment. FIG. 11 is a flowchart (2) illustrating the procedure of the area data adding process according to the first embodiment. FIG. 12 is a flowchart showing the procedure of the overlapping area setting process. FIG. 13 is a diagram illustrating a specific example of the overlapping area setting. FIG. 14 is a flowchart illustrating a processing procedure of a modified example of the overlapping area setting process. FIG. 15 is a functional block diagram illustrating the configuration of the area search server according to the second embodiment. FIG. 16 is a diagram illustrating an example of the data structure of the previous position DB. FIG. 17 is a flowchart (1) illustrating a procedure of search processing according to the second embodiment. FIG. 18 is a flowchart (2) illustrating the procedure of the search process according to the second embodiment. FIG. 19 is a flowchart (3) illustrating a procedure of search processing according to the second embodiment. FIG. 20 is a flowchart (1) illustrating a processing procedure of a modification of the search processing according to the second embodiment. FIG. 21 is a flowchart (2) illustrating the processing procedure of a modification of the search processing according to the second embodiment. FIG. 22 is a diagram illustrating a specific example of the deepest node. FIG. 23 is a diagram for explaining a comparison result of the number of searches. FIG. 24 is a diagram illustrating an example of a computer that executes an area search program. FIG. 25 is a diagram illustrating an example of data managed by the R-tree and a rectangular area.

  Hereinafter, embodiments of a region search method, a region search program, and an information processing device disclosed in the present application will be described in detail with reference to the drawings. The present invention is not limited to the embodiments.

[Area Search Server]
FIG. 1 is a functional block diagram illustrating the configuration of the area search server according to the first embodiment. As illustrated in FIG. 1, the area search server 1 includes a communication interface 11, a storage unit 12, and a control unit 13.

  The communication interface 11 is an interface that establishes communication with each terminal device, receives a region search request from each terminal device, and transmits a region search response to each terminal device. Here, the area search request is a request for searching in which area the position information of the terminal device is included. The position information is, for example, latitude and longitude information where the terminal device exists, but may be information indicating a range in space. The area search request includes, for example, the location information of the terminal device and the sensor identification ID of the terminal device. The area search response is a response corresponding to the area search request and includes the search result. The communication interface 11 is, for example, a network interface card connected to a LAN or the Internet, a wireless communication unit having a wireless antenna, or the like.

  The storage unit 12 stores a program executed by the control unit 13 and includes a region index DB 121 and a region data DB 122. The storage unit 12 is, for example, a semiconductor memory device such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk.

  The area index DB 121 is index information for quickly searching an area that meets a condition from a large number of areas existing in the space. For example, the area index DB 121 holds an index indicating which area is located in the R tree.

  Here, an example of information stored in the area index DB 121 will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of information stored in the region index DB. As shown in FIG. 2, the region index DB 121 stores an R-tree formed by region data indicating any one of a root node, an intermediate node, and a leaf node. A root node is area data of a vertex existing in the R tree. The leaf node is a node at the bottom of the R-tree, and does not include a child node, and has one or more multidimensional area data to be searched. Nodes existing in the middle of other trees are intermediate nodes, each having one or more child nodes.

  In the example of FIG. 2, the root node is R1, and the child nodes and intermediate nodes of R1 are R10 and R11. R1 is a rectangular area including all of the rectangular areas R10 and R11. Leaf nodes that are child nodes of the intermediate node R10 are R100 and R101. R10 is a rectangular area including all the rectangular areas of R100 and R101. Leaf nodes that are child nodes of the intermediate node R11 are R110 and R111. R11 is a rectangular area including all the rectangular areas of R110 and R111. The leaf node R100 has region data 1, 2, and 3 to be searched. The leaf node R101 has area data 4 and 5 to be searched. The leaf node R110 has area data 6 and 7 to be searched. The leaf node R111 has area data 8 and 9 to be searched. The region data 1 to 9 may be region IDs (IDentification) that can identify the region data, for example.

  The area index DB 121 stores information on root, intermediate, and leaf nodes as R-tree entities. FIG. 3 is a diagram illustrating an example of root node information stored in the region index DB. As illustrated in FIG. 3, the region index DB 121 stores “node type, rectangular region, child node list” as information of the root node R1. “Node type” is information indicating whether a node is a root, an intermediate, or a leaf. The “rectangular area” is information of a minimum circumscribed rectangle including all the areas in charge of child nodes. The minimum circumscribed rectangle is a minimum rectangular area including all child node areas. The “child node list” is a list of link pointers to child nodes of the node.

  In the example of FIG. 3, the root node R1 manages two-dimensional data of x and y, “x1 = 35.5, y1 = 139.0” is the minimum point of the assigned area, and “x2 = 35.9 , Y2 = 139.5 ”indicates the maximum point of the assigned area. That is, the region in charge of R1 is a region formed by four straight lines that are perpendicular to each dimension axis with both points as vertices. Also, R1 stores a list of pointers to child nodes “R10, R11”.

  FIG. 4 is a diagram illustrating an example of intermediate node information stored in the region index DB. As illustrated in FIG. 4, the region index DB 121 stores “node type, rectangular region, child node list” as intermediate node information. The “node type”, “rectangular area”, and “child node list” stored here are the same as those in FIG. The area index DB 121 stores information of FIG. 4 for R10 and R11.

  In the case of FIG. 4, the intermediate node R10 manages two-dimensional data of x and y, “x1 = 35.5, y1 = 139.2” is the minimum point of the assigned area, and “x2 = 35.7, “y2 = 139.3” indicates the maximum point of the assigned area. In other words, the region handled by the intermediate node R10 is a region formed by four straight lines that are perpendicular to each dimension axis with both points serving as vertices. In addition, R10 stores a list of pointers to child nodes “R100, R101”.

  FIG. 5 is a diagram illustrating an example of leaf node information stored in the region index DB. As illustrated in FIG. 5, the region index DB 121 stores “node type, rectangular region, data list” as leaf node information. The “node type” and “rectangular area” stored here are the same as those in FIG. 3 and will not be described in detail. The “data list” is multidimensional area data to be managed. The area index DB 121 stores the information in FIG. 5 for R100, R101, R110, and R111.

  In the case of FIG. 5, the leaf node R100 manages two-dimensional data of x and y, “x1 = 35.5, y1 = 139.2” is the minimum point of the assigned area, and “x2 = 35.6, “y2 = 139.3” indicates the maximum point of the assigned area. That is, the area in which the leaf node R100 is in charge is an area formed by four straight lines orthogonal to each dimension axis with both points serving as vertices. The R100 stores a list of pointers to the area data “D1, D2, D3, D4”. As an example of a pointer to the area data, an area ID for identifying the area data is used. The substance of each area data is stored in the area data DB 122.

  Returning to FIG. 1, the area data DB 122 manages a plurality of area data and also manages area data of other areas overlapping with the area data area for each of the plurality of area data.

  Here, an example of the data structure of the area data DB 122 will be described with reference to FIG. FIG. 6 is a diagram illustrating an example of the data structure of the area data DB. As shown in FIG. 6, the area data DB 122 stores a data name 122b, area information 122c, and an overlapping area 122d in association with each area ID 122a. The area ID 122a indicates an ID that can uniquely identify area data. The data name 122b indicates the data name of the area data indicated by the area ID. The area information 122c indicates a specific range that is the substance of the area data indicated by the area ID. The overlapping area 122d indicates the area ID of other area data that overlaps the area data indicated by the area ID. For example, when the area ID 122a is “00001”, the data name 122b is stored as “A store near X store”, and the area information 122c is stored as “circle area: latitude 35.491, longitude 139.650, radius 100 m”. . The area ID “00034” is stored as the overlapping area 122d when the area ID 122a is “00001”.

  Returning to FIG. 1, the control unit 13 includes a request reception unit 131, a response transfer unit 132, a tree search unit 133, an overlap data search unit 134, and an overlap region setting unit 135. The control unit 13 is, for example, an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array) or an electronic circuit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit).

  The request reception unit 131 receives a search request received by the communication interface 11. The response transfer unit 132 transfers the area search response corresponding to the search request to the communication interface 11.

  The tree search unit 133 uses the region index DB 121 to search for a region including predetermined position information. For example, the tree search unit 133 extracts position information from the area search request received by the request reception unit 131. Then, the tree search unit 133 traverses from the root node to the child node in a top-down manner, selects the nodes in order, and determines whether there is a child node of the selected node that includes the extracted position information. Determine using. As an example, the tree search unit 133 reads the child node list of the selected node using the region index DB 121, and further reads the rectangular region of each child node included in the read child node list. Then, the tree search unit 133 determines whether or not the read rectangular area of each child node includes the extracted position information.

  In addition, the tree search unit 133 adds a child node including the extracted position information as a selection candidate node. Then, the tree search unit 133 selects the nodes added as selection candidate nodes one by one, and if the selected node is a leaf node, the tree search unit 133 includes the extracted location information in the region data in the leaf node. It is determined using the region index DB 121 whether or not there is. As an example, the tree search unit 133 uses the region index DB 121 to read a data list of nodes that are leaf nodes, and extracts a pointer to the region data included in the read data list. Here, assuming that the area data is an area ID, the tree search unit 133 uses the area information 122c stored in the area data DB 122 to include the extracted position information in the area information 122c corresponding to the area ID. It is determined whether or not. Then, if there is at least one area information 122c including the extracted position information in the area information 122c corresponding to the area ID, the tree search unit 133 adds the area ID of any one of the area information 122c to the search result. The search using the index DB 121 is terminated. In addition, when there are a plurality of pieces of region information including position information, the tree search unit 133 desirably selects region information having the smallest number of overlapping regions. This is for the purpose of reducing the number of overlapping areas to be searched because the overlapping data searching unit 134 described later searches for an area further including position information from the overlapping area of the selected area information.

  When the tree search unit 133 can search the area information including the position information, the duplicate data search unit 134 can select from the overlap areas corresponding to the searched area information based on the overlap area stored in the area data DB 122. Search area information including position information. For example, the duplicate data search unit 134 extracts the area ID from the search result added by the tree search unit 133. Then, based on the overlapping area 122d stored in the area data DB 122, the overlapping data search unit 134 reads the area ID of the overlapping area that overlaps the area information of the extracted area ID. Then, the duplicate data search unit 134 selects area IDs of the corresponding overlap areas one by one, and determines whether or not the overlap area of the selected area ID includes position information. And the duplication data search part 134 adds area ID of the duplication area | region containing position information to a search result.

  The overlapping area setting unit 135 sets an overlapping area in the area data DB 122. When adding a new area to the area index DB 121, the overlapping area setting unit 135 may add the added area to the area data DB 122 and set an overlapping area that overlaps the added area. . For example, the overlapping area setting unit 135 selects nodes in order from the root node toward the child node, and uses the area index DB 121 to determine whether or not there is an additional area among the child nodes of the selected node. judge. As an example, the overlapping area setting unit 135 reads the child node list of the selected node using the area index DB 121, and further reads the rectangular area of each child node included in the read child node list. Then, the overlapping area setting unit 135 determines whether there is an area including an additional area in the read rectangular area of each child node.

  In addition, the overlapping area setting unit 135 adds a child node including the additional area as a selection candidate node. Then, the overlapping area setting unit 135 selects the nodes added as selection candidate nodes one by one, and if the selected node is a leaf node, a part overlapping with the additional area in the area data in the leaf node is displayed. A certain area data is selected as an overlapping area. Then, the overlapping area setting unit 135 adds the area data selected as the overlapping area to the overlapping area 122d corresponding to the additional area of the area data DB 122. Furthermore, the overlapping area setting unit 135 adds the additional area to the overlapping area 122d corresponding to the area data selected as the overlapping area.

[Example of area search request data]
Next, the contents of the area search request received by the request receiving unit 131 via the communication interface 11 will be described with reference to FIG. FIG. 7 is a diagram showing an example of the contents of the area search request. As shown in FIG. 7, the area search request includes a sensor ID for identifying the sensor, and a latitude and longitude. Latitude and longitude are examples of position information. In the example of FIG. 7, “Sensor000X” is set as the sensor ID, “35.4134” is set as the latitude, and “139.6252” is set as the longitude. The area search request includes the sensor ID. However, the present invention is not limited to this, and may be the device ID of the terminal device that requests the area search, or the mobile phone of the mobile phone that requests the area search. It may be a number.

[Example of area search response data]
Next, the contents of the area search response output by the response transfer unit 132 via the communication interface 11 will be described with reference to FIG. FIG. 8 is a diagram illustrating an example of the contents of the region search response. As shown in FIG. 8, the area search response is a list of area information indicating the result of area search, and includes an area ID and an area name corresponding to the area information. In the example of FIG. 8, “00001” is set as the area ID, and “A store X store vicinity” is set as the area name. In addition, “00034” is set as the area ID and “Restaurant C neighborhood” is set as the area name. The region information list includes the region ID and the region name, but is not limited thereto, and may include the region position, size, shape, and the like.

[Request reception processing procedure]
Next, the procedure of the request reception process related to the search will be described with reference to FIG. 9A. FIG. 9A is a flowchart illustrating a procedure of request reception processing related to search.

  First, the request reception unit 131 determines whether an area search request has been received (S10A). If it is determined that the area search request has not been received (step S10A; No), the request reception unit 131 repeats the determination process until the area search request is received. On the other hand, when it determines with having received the area | region search request | requirement (step S10A; Yes), the request reception part 131 performs a search process (step S10B).

  Then, the request reception unit 131 determines whether or not the request reception process has ended (step S10C). If it is determined that the request reception process has not been completed (step S10C; No), the request reception unit 131 proceeds to step S10A. On the other hand, if it is determined that the request reception process has been completed (step S10C; Yes), the request reception unit 131 ends the process.

[Search process steps]
Next, the search process shown in step S10B of FIG. 9A will be described with reference to FIG. 9B. FIG. 9B is a flowchart illustrating the search processing procedure according to the first embodiment. In the example of FIG. 9B, the position information included in the area search request will be described as search coordinates.

  When the area search request is received by the request reception unit 131, the tree search unit 133 selects a root node based on the area index DB 121 (step S11). Then, the tree search unit 133 determines whether or not the selected node selected is a leaf node (step S12).

  If it is determined that the selected node is not a leaf node (step S12; No), the tree search unit 133 determines whether or not there is a child node of the selected node that includes the search coordinates using the region index DB 121 ( Step S13). As an example, the tree search unit 133 reads the child node list of the selected node based on the region index DB 121, and reads the rectangular region of each child node included in the read child node list. Then, the tree search unit 133 determines whether or not the read rectangular area of each child node includes a search coordinate.

  When it is determined that there is a child node of the selected node that includes the search coordinate (step S13; Yes), the tree search unit 133 adds the child node including the search coordinate to the selection candidate node (step S14), and step S15. Migrate to On the other hand, when it is determined that no child node of the selected node includes the search coordinate (step S13; No), the tree search unit 133 proceeds to step S15.

  Subsequently, the tree search unit 133 determines whether or not all selection candidate nodes have been searched (step S15). When it is determined that the search of all selection candidate nodes has not been completed (step S15; No), the tree search unit 133 selects one unsearched node in the selection candidate nodes (step S16), and proceeds to step S12. To do.

  In step S12, when it is determined that the selected node is a leaf node (step S12; Yes), the tree search unit 133 determines whether there is a region including the search coordinates in the area data of the selected leaf node. Determination is made (step S17). As an example, the tree search unit 133 reads a data list of nodes that are leaf nodes based on the region index DB 121, and extracts a pointer to the region data included in the read data list, for example, a region ID. Then, based on the area data DB 122, the tree search unit 133 determines whether there is an area information 122c corresponding to the extracted area ID that includes the search coordinates.

  If it is determined that none of the area data held by the selected leaf node includes the search coordinates (step S17; No), the tree search unit 133 proceeds to step S15 to search for the next selection candidate node. .

  On the other hand, when it is determined that there is a search coordinate included in the area data of the selected leaf node (step S17; Yes), the tree search unit 133 has the smallest number of overlapping areas in the corresponding area data. The area data is added to the search result (step S18). As an example, the tree search unit 133 adds region data (region ID) having the smallest number of overlapping regions to the search result based on the overlapping region 122d stored in the region data DB 122. Here, the search using the region index DB 121 is terminated.

  Subsequently, based on the overlapping region 122d of the region data DB 122, the overlapping data search unit 134 reads an undetermined one from the overlapping regions of the region data added to the search result, and selects one read overlapping region (step) S19). Then, the duplicate data search unit 134 determines whether or not the selected overlap area includes the search coordinates (step S20). When it is determined that the selected overlapping area includes the search coordinates (step S20; Yes), the overlapping data search unit 134 adds the area ID of the overlapping area determined to include (step S21) to step S22. Transition.

  On the other hand, if it is determined that the selected overlapping area does not include the search coordinates (step S20; No), the overlapping data search unit 134 determines that the entire overlapping area has not been determined (step S22; No), and the next overlap. To determine the area, the process proceeds to step S19. On the other hand, the duplicate data search unit 134 outputs the created search result to the response transfer unit 132 in order to return the created search result to the inquiry side (step S23) when the determination of all the overlapping regions is completed (step S22; Yes). Thereafter, the response transfer unit 132 transmits the search result as an area search response to the inquiry side of the area search request.

  In step S15, when it is determined that the search of all selection candidate nodes has been completed (step S15; Yes), the tree search unit 133 determines that there is no search result in the selected node, so the inquiry side Is output to the response transfer unit 132 (step S24). Thereafter, the response transfer unit 132 transmits the search result as an area search response to the inquiry side of the area search request.

[Procedure for adding area data]
Next, the procedure of region data addition processing according to the first embodiment will be described with reference to FIGS. 10 and 11 are flowcharts illustrating the procedure of the area data adding process according to the first embodiment.

  First, the overlapping area setting unit 135 selects a root node based on the area index DB 121 (step S31). Then, the overlapping area setting unit 135 determines whether or not the selected node selected is a leaf node (step S32).

  When it is determined that the selected node is not a leaf node (step S32; No), the overlapping area setting unit 135 determines whether there is a child node of the selected node that includes an additional area based on the area index DB 121. (Step S33). As an example, the overlapping area setting unit 135 reads the child node list of the selected node based on the area index DB 121, and reads the rectangular area of each child node included in the read child node list. Then, the tree search unit 133 determines whether or not there is a rectangular area including the additional area in the read rectangular area of each child node.

  If it is determined that there is an additional region included (step S33; Yes), the overlapping region setting unit 135 selects a child node including the additional region having the smallest rectangular area as a selection node ( Step S34). Then, the overlapping area setting unit 135 proceeds to step S32.

  On the other hand, when it is determined that there is no object including the additional area (step S33; No), the overlapping area setting unit 135 selects a child node whose amount of enlargement is minimum when the additional area is included (step S35). . Then, the overlapping area setting unit 135 proceeds to step S32.

  If it is determined in step S32 that the selected node is a leaf node (step S32; Yes), the overlapping area setting unit 135 proceeds to step S41.

  Subsequently, the overlapping area setting unit 135 adds area data of the additional area to the selected leaf node (step S41). As an example, the overlapping area setting unit 135 adds a pointer to area data of the additional area, for example, an area ID, to the data list of the corresponding leaf node in the area index DB 121. Then, the overlapping area setting unit 135 executes an overlapping area setting process (step S42).

  Here, the number of area data of the selected leaf node may exceed the upper limit. In this case, the overlapping area setting unit 135 performs the following processing. The overlapping area setting unit 135 determines whether or not the number of area data held by the selected leaf node exceeds the upper limit (step S43). When the number of area data exceeds the upper limit (step S43; Yes), the overlapping area setting unit 135 leaves the sum of the sizes of the rectangular areas as a result of division when the rectangular area of the leaf node is divided. The node is divided into two and added to the parent node (step S44). On the other hand, when the number of area data does not exceed the upper limit (step S43; No), the overlapping area setting unit 135 ends the area data adding process.

  Furthermore, the number of child nodes of the parent node to be added may exceed the upper limit. In this case, the overlapping area setting unit 135 performs the following processing. The overlapping area setting unit 135 determines whether or not the number of child nodes of the parent node to be added exceeds the upper limit (step S45). When the number of child nodes of the parent node to be added exceeds the upper limit (step S45; Yes), the overlapping area setting unit 135 determines whether or not the parent node to be added is a root node (step S46). On the other hand, when the number of child nodes of the parent node to be added does not exceed the upper limit (step S45; No), the overlapping area setting unit 135 ends the area data adding process.

  When it is determined that the parent node to be added is not the root node (step S46; No), the overlapping area setting unit 135 divides the node so that the sum of the sizes of the rectangular areas obtained as a result of the division is minimized. Then, the overlapping area setting unit 135 adds the increased node after the division to the parent node of the node that is the division source (step S47). Then, the overlapping area setting unit 135 proceeds to step S45.

  On the other hand, when it is determined that the parent node to be added is the root node (step S46; Yes), the overlapping area setting unit 135 divides the current root node and creates a new root node on the current root node. (Step S48). Then, the overlapping area setting unit 135 ends the area data adding process.

[Overlapping area setting procedure]
Next, the overlapping area setting process shown in step S42 of FIG. 11 will be described with reference to FIG. FIG. 12 is a flowchart showing the procedure of the overlapping area setting process.

  The overlapping area setting unit 135 selects a root node based on the area index DB 121 (step S51). Then, the overlapping area setting unit 135 determines whether or not the selected node selected is a leaf node (step S52).

  When it is determined that the selected node is a leaf node (step S52; Yes), the overlapping area setting unit 135 selects, as the overlapping area, an area of the area data that overlaps the additional area from among the area data in the selected node (step S52). S53). As an example, the overlapping area setting unit 135 reads the data list of the selected node based on the area index DB 121, and extracts a pointer to area data included in the read data list, for example, an area ID. Then, based on the area data DB 122, the overlapping area setting unit 135 selects, as an overlapping area, an area ID that has a portion that overlaps the additional area among the extracted area IDs. Then, the overlapping area setting unit 135 proceeds to step S56.

  On the other hand, when it is determined that the selected node is not a leaf node (step S52; No), the overlapping area setting unit 135 determines whether there is an overlapping area with the additional area among the child nodes of the selected node based on the area index DB 121. Determination is made (step S54). When it is determined that there is an overlapping area in the child node of the selected node (step S54; Yes), the overlapping area setting unit 135 adds the overlapping child node to the selection candidate node (step S55), and proceeds to step S56. To do. On the other hand, when it is determined that no child node of the selected node overlaps the additional area (step S54; No), the overlapping area setting unit 135 proceeds to step S56.

  Subsequently, the overlapping area setting unit 135 determines whether or not all the selection candidate nodes have been searched (step S56). When it is determined that the search of all selection candidate nodes has not been completed (step S56; No), the overlapping area setting unit 135 selects one unsearched node in the selection candidate nodes (step S57), and the process proceeds to step S52. Transition.

  On the other hand, when it is determined that all the selection candidate nodes have been searched (step S56; Yes), the overlapping area setting unit 135 adds the selected overlapping area to the overlapping area of the additional area (step S58). As an example, the overlapping area setting unit 135 adds the area data selected as the overlapping area to the overlapping area 122 d corresponding to the additional area of the area data DB 122.

  Further, the overlapping area setting unit 135 adds an additional area as an overlapping area to each selected overlapping area (step S59). As an example, the overlapping area setting unit 135 adds the additional area to the overlapping area 122 d corresponding to each area data selected as the overlapping area of the area data DB 122. Then, the overlapping area setting unit 135 ends the overlapping area setting process.

[Specific example of overlapping area setting]
Here, a specific example of overlapping area setting will be described with reference to FIG. FIG. 13 is a diagram illustrating a specific example of the overlapping area setting. In the example of FIG. 13, it is assumed that region IDs “00001” and “00002” are set as region data in the data list of the selected leaf node. Further, the additional area is “00034” as the area ID, “Restaurant C neighborhood” as the data name, and “Circle area: latitude 35.492, latitude 139.650, radius 100 m” as the area information.

  The overlapping area setting unit 135 selects, as the overlapping area, the area of the area data that overlaps the additional area among the area data in the selected leaf node. Here, since there is a portion that overlaps the region, the overlapping region setting unit 135 selects the overlapping region as the region ID “00001” as the region data in the leaf node. Further, the overlapping area setting unit 135 does not select the overlapping area because there is no overlapping area with respect to the area ID “00002” as the area data in the leaf node.

  Then, the overlapping area setting unit 135 adds the area ID selected as the overlapping area to the overlapping area column of the additional area of the area data DB 122. Here, the overlapping area setting unit 135 adds the area ID “00001” to the overlapping area R1 corresponding to the area ID “00034” of the area data DB 122.

  Furthermore, the overlapping area setting unit 135 adds the area ID of the additional area to the overlapping area column of each overlapping area in the area data DB 122. Here, the overlapping area setting unit 135 adds the area ID “00034” of the additional area to the overlapping area R2 corresponding to the area ID “00001” of the overlapping area of the area data DB 122.

  In this way, the overlapping area setting unit 135 adds the additional area and each overlapping area overlapping with the additional area to the overlapping area column of the area data DB 122. However, when the additional region is a wide region such as a region having a radius of 10 km from the city center, the number of overlapping regions overlapping with the additional region may be extremely large. In such a case, the overlapping area setting unit 135 does not add the overlapping area to the overlapping area column of the additional area, and continues the index DB search when the area becomes a search result during the search. Also good. This is because if the number of overlapping areas to be added to the overlapping area column is extremely large, the search processing by the overlapping data search unit 134 takes time.

  Therefore, as a modification of the process of the overlap area setting unit 135, a process for not adding an overlap area to the overlap area column of the add area when the number of overlap areas overlapping with the add area is a predetermined number or more will be described. . The predetermined number is, for example, “200”, 10 times the upper limit of the number of child nodes of the index tree, or 0.1% of the total area data number. However, the number of overlapping regions is not limited to this, and any number of overlapping regions that do not cause a delay in search processing may be used.

[Procedure of modified example of overlapping area setting process]
FIG. 14 is a flowchart illustrating the procedure of a modified example of the overlapping area setting process. Note that the same processes S51 to S59 as those of the overlapping area setting unit 135 shown in FIG. 12 are denoted by the same reference numerals, and the description of the overlapping processes is omitted. The processing of the overlapping area setting unit 135 shown in FIG. 14 is different from the processing of the overlapping area setting unit 135 shown in FIG. 12 in that S61 is added.

  The overlapping area setting unit 135 determines whether or not the search for all selection candidate nodes has been completed, and determines that the search for all selection candidate nodes has been completed (step S56; Yes), the overlapping area overlapping with the additional area It is determined whether the number is equal to or greater than a predetermined number (step S61). If the number of overlapping areas overlapping with the additional area is not equal to or greater than the predetermined number (step S61; No), the overlapping area setting unit 135 adds the selected overlapping area to the overlapping area of the additional area (step S58). Subsequently, the overlapping area setting unit 135 adds an additional area as an overlapping area to each selected overlapping area (step S59).

  On the other hand, when the number of overlapping areas overlapping with the additional area is equal to or greater than the predetermined number (step S61; Yes), the overlapping area setting unit 135 does not add the selected overlapping area to the overlapping area of the additional area, and overlaps. A special value “overlapping multiple” is recorded in the area (step S62). Then, the overlapping area setting unit 135 adds an additional area as an overlapping area to each selected overlapping area (step S59).

  Note that there may be a case where area data (area ID) recorded as “overlapping multiple multiples” is added to the overlapping area by the overlapping area setting process. In this case, even if the search processing adds this area data to the search result, the search using the area index DB 121 is continued without using this area data. Specifically, in step S18 of the search process of FIG. 9B, the tree search unit 133 adds area data having the smallest number of overlapping areas among the corresponding area data to the search result. As an example, the tree search unit 133 adds region data (region ID) having the smallest number of overlapping regions to the search result based on the overlapping region 122d stored in the region data DB 122. Here, if there is only area data recorded as “overlapping multiple” in the search result, the tree search unit 133 does not use this area data, and continues the search using the area index DB 121 in step S15. You should move to.

[Effect of Example 1]
According to the first embodiment, the area search server 1 uses the index information used when searching for an area and includes the area information including a plurality of areas as index information for managing the area as the area index DB 121. To remember. Then, the area search server 1 searches for an area including a predetermined position using an index tree that represents the index information stored in the area index DB 121 in a tree structure. Then, when the area search server 1 can search the area including the position, the area search server 1 searches for the area including the position from the overlapping areas of the areas that can be searched based on the overlapping area stored in the area data DB 122. . Then, the area search server 1 outputs information on the area that can be searched. According to such a configuration, the area search server 1 ends the search using the index tree when the area including the predetermined position can be searched using the index tree, and uses the overlapping area of the searched areas. We decided to move to search. For this reason, if the area search server 1 can search for one area including a predetermined position using the index tree, the area search server 1 may search for an area including the position from among the overlapping areas of the searched areas. The search time of area search including can be increased.

  By the way, in the area search server 1 according to the first embodiment, an area including a query position is searched using an index tree, and when the area can be searched, an overlapping area overlapping with the searched area is searched as a search target. Explained the case. However, the area search server 1 is not limited to this, and the area that has been searched may be recorded as the area that has been searched the last time in order to be used for the next search. Therefore, in the second embodiment, an area search server 2 that records an area that can be searched as an area that was previously searched will be described.

[Configuration of Area Search Server According to Second Embodiment]
FIG. 15 is a functional block diagram illustrating the configuration of the area search server according to the second embodiment. The same components as those of the area search server 1 shown in FIG. 1 are indicated by the same reference numerals, and the description of the overlapping components and operations is omitted. The difference between the first embodiment and the second embodiment is that the previous position DB 201 is added to the storage unit 12. The difference between the first embodiment and the second embodiment is that a previous area search unit 202 and a previous area recording unit 203 are added to the control unit 13.

  The previous position DB 201 manages position information that can be searched when a previous area search request is made in association with the request source. Here, an example of the data structure of the previous position DB 201 will be described with reference to FIG. FIG. 16 is a diagram illustrating an example of the data structure of the previous position DB 201. As shown in FIG. 16, the previous position DB 201 stores the previous search area 201b in association with each sensor ID 201a. The sensor ID 201a indicates the identification ID of the sensor that has requested the area search request. The previous search area 201b indicates area information that can be searched when a previous area search request is made. For example, in the previous search area 201b, the area ID of the area that can be searched when the search is successful is stored, and “undetected” is stored when the search is not possible. For example, when the sensor ID 201a is “Sensor0001”, “undetected” is stored as the previous search area 201b. Further, when the sensor ID 201a is “Sensor0002”, “region ID00034” is stored as the previous search region 201b.

  Returning to FIG. 15, the previous area search unit 202 searches for an area including predetermined position information using the area that was searched when the previous area search was performed. For example, the previous area search unit 202 extracts the sensor ID and the position information from the area search request received by the request reception unit 131. Then, the previous area search unit 202 determines whether or not the previous search area of the extracted sensor ID is stored in the previous position DB 201. When the previous search area of the sensor ID is stored, the previous area search unit 202 determines whether or not the position information extracted from the area search request is included in the previous search area. Then, when the extracted position information is included in the previous search area, the previous area search unit 202 adds the previous search area to the search result, and ends the search process of the previous area search unit 202. Thereafter, based on the overlapping area stored in the area data DB 122, the overlapping data search unit 134 searches for an overlapping area including the position information from among the overlapping areas corresponding to the search results. Then, the duplicate data search unit 134 adds the area ID of the duplicate area that can be searched to the search result.

  Further, when the extracted position information is not included in the previous search area, the previous area search unit 202 causes the tree search unit 133 to search for an area including the position information. That is, the tree search unit 133 uses the region index DB 121 to search a region including the position information from leaf nodes having the previous search region as region data.

  If there is area data including the position information among the area data of the leaf node, the tree search unit 133 adds the searched area data to the search result. Thereafter, based on the overlapping area stored in the area data DB 122, the overlapping data search unit 134 searches for an overlapping area including the position information from among the overlapping areas corresponding to the search results. On the other hand, if there is no area data including the position information among the area data of the leaf node, the tree search unit 133 sequentially traces the nodes from the child node to the root node in a bottom-up manner and includes the position information. Select a node. Then, the tree search unit 133 uses the region index DB 12 to determine whether there is a child node of the selected node that includes the position information. Then, the tree search unit 133 adds a child node including the position information as a selection candidate node. Then, the tree search unit 133 selects the nodes added as selection candidate nodes one by one, and if the selected node is a leaf node, the region data including the position information is included in the region data in the leaf node. It is determined using the region index DB 121 whether or not there is. Then, if there is at least one region data including the position information, the tree search unit 133 adds any one region data to the search result, and ends the search using the region index DB 121. Thereafter, based on the overlapping area stored in the area data DB 122, the overlapping data search unit 134 searches for an overlapping area including the position information from among the overlapping areas corresponding to the search results. Then, the duplicate data search unit 134 adds the area ID of the duplicate area that can be searched to the search result.

  Further, the previous area search unit 202 shifts to a search process by the tree search unit 133 and the duplicate data search unit 134 when the previous search area of the sensor ID is not stored. Note that the search processing performed by the tree search unit 133 and the duplicate data search unit 134 is as described in the first embodiment, and thus the description thereof is omitted.

  The previous area recording unit 203 records the search result in the previous position DB 201 in association with the sensor ID of the request source that requested the area search. Here, there may be a plurality of area IDs that can be searched in the search result. In such a case, the previous area recording unit 203 may select an area ID having the smallest number of overlapping areas from among a plurality of area IDs, and record the selected area ID in the previous position DB 201. As a result, in the next area search request, if the position information of the area search request is included in the area of the previously recorded area ID, the number of searches related to the overlapping area that overlaps with the area can be reduced. This is because that.

[Search process steps]
Next, a search process procedure according to the second embodiment will be described with reference to FIGS. FIGS. 17 to 19 are flowcharts illustrating the procedure of the search process according to the second embodiment. In the examples of FIGS. 17 to 19, the position information included in the area search request is described as search coordinates.

  First, when an area search request is received by the request receiving unit 131, the previous area search unit 202 determines whether or not the previous data (previous search area) of the inquired sensor ID is stored in the previous position DB 201 (step S71). When it is determined that the previous data of the sensor ID of the inquiry is stored in the previous position DB 201 (step S71; Yes), the previous area search unit 202 determines whether the search coordinates are in the previous data (step). S72). When the search coordinates are in the previous data (step S72; Yes), the previous area search unit 202 adds the previous data as the corresponding data to the search result (step S73).

  Subsequently, based on the overlapping region 122d of the region data DB 122, the overlapping data search unit 134 reads an undetermined one from the overlapping regions of the region data added to the search result, and selects one read overlapping region (step) S74). Then, the duplicate data search unit 134 determines whether or not the selected overlap area includes a search coordinate (step S75). When it is determined that the selected overlapping area includes the search coordinates (step S75; Yes), the overlapping data search unit 134 adds the area ID of the overlapping area determined to include (step S76) to step S77. Transition.

  On the other hand, when it is determined that the selected overlapping area does not include the search coordinates (step S75; No), the overlapping data search unit 134 determines that the entire overlapping area has not been determined (step S77; No), and the next overlap. In order to determine the area, the process proceeds to step S74. On the other hand, when the determination of all the overlapping areas is completed (step S77; Yes), the duplicate data search unit 134 outputs the created search result to the response transfer unit 132 in order to reply to the inquiry side (step S78). Then, the previous area recording unit 203 records one area ID of the search results created by the duplicate data search unit 134 in the previous position DB 201 in association with the inquiry sensor ID (step S79), and ends the search process. To do.

  In step S71, when the previous data of the inquired sensor ID is not stored in the previous position DB 201 (step S71; No), the previous area search unit 202 should shift to a search process for tracing the node from the root node to the top down. The process proceeds to step S11.

  In step S72, when the search coordinates are not in the previous data (step S72; No), the previous area search unit 202 shifts to step S80 in order to shift to a search process for tracing the node bottom up.

  In step S80, based on the region index DB 121, the tree search unit 133 selects a leaf node or parent node having the previous data in the data list as region data (step S80). Then, the tree search unit 133 determines whether or not the selected selection node includes the search coordinates by using the region index DB 121 (step S81). If it is determined that the selected node includes the search coordinates (step S81; Yes), the tree search unit 133 proceeds to step S91 in order to further shift to a search process that traces the node from the selected node to the top down.

  On the other hand, when it is determined that the selected node does not include the search coordinates (step S81; No), the tree search unit 133 determines whether or not the selected node is the root node using the region index DB 121 (step S82). ). If the selected node is not the root node (step S82; No), the tree search unit 133 proceeds to step S80 to search for the parent node.

  On the other hand, if the selected node is the root node (step S82; Yes), the tree search unit 133 outputs to the response transfer unit 132 in order to reply to the inquiry side that there is no search result (step S83). Then, the previous area recording unit 203 records in the previous position DB 201 that it has not been detected in association with the inquiry sensor ID (step S84), and ends the search process.

[Procedure for search processing when previous data is not stored in previous position DB]
Next, the procedure of search processing when the previous data is not stored in the previous position DB 201 shown in step S71 of FIG. 17 will be described with reference to FIG. As shown in FIG. 18, steps S11 to S24 are the same processing procedure as in FIG. The difference between FIG. 9 and FIG. 18 is that the previous area recording unit 203 records the search result.

  When the duplicate data search unit 134 finishes determining all the overlapping regions (step S22; Yes), the created search result is output to the response transfer unit 132 to reply to the inquiry side (step S23). Then, the previous area recording unit 203 records one area ID of the search results created by the duplicate data search unit 134 in association with the inquiry sensor ID in the previous position DB 201 (step S23A), and ends the search process. To do.

  When the tree search unit 133 finishes searching all the selection candidate nodes (step S15; Yes), it outputs to the response transfer unit 132 to reply to the inquiry side that there is no search result (step S24). Then, the previous area recording unit 203 records in the previous position DB 201 that it has not been detected in association with the inquiry sensor ID (step S24A), and ends the search process.

[Procedure for search processing when the selected node contains search coordinates]
Next, the procedure of search processing when the selected node shown in step S81 of FIG. 17 includes search coordinates will be described with reference to FIG.

  The tree search unit 133 determines whether the selected node including the search coordinates is a leaf node using the region index DB 121 (step S91).

  When it is determined that the selected node is not a leaf node (step S91; No), the tree search unit 133 determines whether or not there is a child node of the selected node that includes the search coordinates using the region index DB 121 ( Step S92). As an example, the tree search unit 133 reads the child node list of the selected node based on the region index DB 121, and reads the rectangular region of each child node included in the read child node list. Then, the tree search unit 133 determines whether or not the read rectangular area of each child node includes a search coordinate.

  If it is determined that there is a child node of the selected node that includes the search coordinate (step S92; Yes), the tree search unit 133 adds the child node including the search coordinate to the selection candidate node (step S93), and step S94. Migrate to On the other hand, when it is determined that no child node of the selected node includes the search coordinate (step S92; No), the tree search unit 133 proceeds to step S94.

  Subsequently, the tree search unit 133 determines whether or not all selection candidate nodes have been searched (step S94). When it is determined that the search of all selection candidate nodes has not been completed (step S94; No), the tree search unit 133 selects one unsearched node in the selection candidate nodes (step S95), and proceeds to step S91. To do.

  If it is determined in step S91 that the selected node is a leaf node (step S91; Yes), the tree search unit 133 determines whether or not there is a region including the search coordinates in the area data of the selected leaf node. Determination is made (step S96). As an example, the tree search unit 133 reads a data list of nodes that are leaf nodes based on the region index DB 121, and extracts a pointer to the region data included in the read data list, for example, a region ID. Then, based on the area data DB 122, the tree search unit 133 determines whether there is an area information 122c corresponding to the extracted area ID that includes the search coordinates.

  If it is determined that none of the area data held by the selected leaf node includes the search coordinates (step S96; No), the tree search unit 133 proceeds to step S94 to search for the next selection candidate node. .

  On the other hand, if it is determined that there is the area data included in the selected leaf node that includes the search coordinates (step S96; Yes), the tree search unit 133 searches one of the area data as the corresponding data. It adds to a result (step S97). Here, the search using the region index DB 121 is terminated, and the process proceeds to step S74. Note that the tree search unit 133 may add region data with the smallest number of overlapping regions to the search result as one of the corresponding region data. This is to reduce the number of overlapping areas to be searched when searching for an area further including the search coordinates in the processing of the overlapping data search unit 134 after step S74.

  In step S94, when it is determined that the search of all selection candidate nodes has been completed (step S94; Yes), the tree search unit 133 does not include a search coordinate in the selected node. Control goes to step S80.

  In this way, the overlapping area setting unit 135 records the area data in the previous position DB 201 when the area coordinates include the search coordinates (position information) of the area search request. In addition, when the search coordinate (position information) is not included in the area data at all, the tree search unit 133 records that it has not been detected in the previous position DB 201. However, even if the tree search unit 133 does not include any search coordinates (position information) in the region data, if there is a node including the search coordinates, the tree search unit 133 sets the deepest node (deepest node) among the nodes to the previous position. You may make it record in DB201. This is because it is possible to increase the probability of hitting an area search and reduce the number of searches by performing an area search from the deepest node among the nodes including the previous search coordinates at the time of the next area search request. Because there is sex.

[Procedure of modified search process]
20 and 21 are flowcharts illustrating the procedure of a modification of the search process according to the embodiment. In addition, about the process S71-S83 same as the search process shown in FIG. 17, the description is abbreviate | omitted by showing the same code | symbol. In addition, the same processes S91 to S97 as the search process in the case where the selected node includes the search coordinates shown in FIG. 19 are denoted by the same reference numerals, and the description of the overlapping processes is omitted.

  The search process shown in FIG. 20 is different from the search process shown in FIG. 17 in that S91 and S92 are added. As shown in FIG. 20, the previous area search unit 202 determines whether or not the previous data (previous search area) of the inquired sensor ID is stored in the previous position DB 201 (step S71). When it is determined that the previous data of the sensor ID of the inquiry is stored in the previous position DB 201 (step S71; Yes), the previous area search unit 202 determines whether the previous data is area data (area ID) ( Step S91). If the previous data is area data (step S91; Yes), the previous area search unit 202 proceeds to step S72. On the other hand, when the previous data is not area data (step S91; No), the previous area search unit 202 selects the node of the previous data (step S92), and proceeds to step S81.

  Further, the search process shown in FIG. 20 is different from the search process shown in FIG. 17 in that S121 to S123 are added. As illustrated in FIG. 20, the tree search unit 133 determines whether or not the selected node is a root node by using the region index DB 121 (step S82). If the selected node is not the root node (step S82; No), the tree search unit 133 proceeds to step S80 to search for the parent node. On the other hand, if the selected node is the root node (step S82; Yes), the tree search unit 133 outputs to the response transfer unit 132 in order to reply to the inquiry side that there is no search result (step S83). Then, the previous area recording unit 203 determines whether or not there is the deepest applicable node (step S121). If there is the deepest applicable node (step S121; Yes), the previous area recording unit 203 records the deepest applicable node in the previous position DB 201 in association with the inquired sensor ID (step S122), and ends the search process. On the other hand, if there is no deepest applicable node (step S121; No), the previous area recording unit 203 records in the previous position DB 201 that it has not been detected in association with the sensor ID of the inquiry (step S123), and performs the search process. finish.

  The search process when the selected node includes the search coordinates shown in FIG. 21 is different from the similar search process shown in FIG. 19 in that S101 and S102 are added. As shown in FIG. 21, the tree search unit 133 determines whether or not the selected node is deeper than the deepest corresponding node (step S101). If the selected node is deeper than the deepest relevant node (step S101; Yes), the tree search unit 133 temporarily records the selected node as the deepest relevant node in the storage unit 12 (step S102), and proceeds to step S91. . On the other hand, when the selected node is not deeper than the deepest corresponding node (step S101; No), the tree search unit 133 proceeds to step S91.

  21 is different from the similar search process shown in FIG. 19 in that the search process when the selected node includes search coordinates is that S103 and S104 are added. As shown in FIG. 21, when the selected node is not a leaf node (step S91; No) and when there is a child node of the selected node that includes a search coordinate (step S92; Yes), the tree search unit 133 Process. The tree search unit 133 adds a child node including the search coordinates to the selection candidate node (step S93), and determines whether the child node is deeper than the deepest corresponding node (step S103). If the child node is deeper than the deepest applicable node (step S103; Yes), the tree search unit 133 temporarily records the child node as the deepest applicable node in the storage unit 12 (step S104), and proceeds to step S94. To do. On the other hand, when the child node is not deeper than the deepest corresponding node (step S103; No), the tree search unit 133 proceeds to step S94.

[Description of deepest node]
Here, a specific example of the deepest node will be described with reference to FIG. FIG. 22 is a diagram illustrating a specific example of the deepest node. As shown in FIG. 22, the root node R0 is a rectangular area including all the rectangular areas of the intermediate nodes R1 to R4, and the intermediate node R1 is a rectangular area including all of the rectangular areas of the child nodes R5 to R8. If the position information of the area search request is a search coordinate indicated by P0, the search coordinate P0 is included in the root node R0 and included in the intermediate node R1. However, the search coordinate P0 is not included in the intermediate nodes R2 to R4 or the child nodes R5 to R8 included in the intermediate node R1. Therefore, the tree search unit 133 sets the deepest node as R1 which is the deepest node among the nodes including the search coordinates P0. Then, the previous area recording unit 203 records the deepest node R1 in the previous position DB 201 in association with the sensor ID of the area search request.

[Effect of Example 2]
According to the second embodiment, when the area search server 2 obtains an area search request including a predetermined position, the area search server 2 determines whether or not the position is included in an area that has been previously searched. Then, as a result of the determination, when it is determined that the position is included in the previously searched area, the area search server 2 selects the area from the overlapping areas of the areas determined to be included based on the area data DB 122. Search for the area containing the location. According to such a configuration, the area search server 2 performs the next area search from the area where the previous search was successful. If the requester who makes an area search request moves only a small moving distance with respect to the size of the area, the position of the next area search request is likely to be in the vicinity of the area where the previous search was possible. Become. For this reason, the area search server 2 can speed up the search time of the area search including the next position by performing the next area search from the previously searched area.

  Further, according to the second embodiment, when the area search server 2 obtains an area search request including a predetermined position, the area search server 2 determines whether or not the position is included in an area that has been previously searched. Then, as a result of the determination, if it is determined that the position is not included in the previously searched area, the area search server 2 includes an area determined not to be included in the nodes forming the tree structure. A region including the position is searched from the leaf node of the index. Then, when the area search server 2 can search for the area including the position, the area search server 2 searches for the area including the position from the overlapping areas of the searched information. According to such a configuration, the area search server 2 performs the next area search from the area where the previous search was successful. If the requester who makes an area search request moves only a small moving distance with respect to the size of the area, the position of the next area search request is likely to be in the vicinity of the area where the previous search was possible. Become. For this reason, even if the position of the next area search request is not included in the previous search area, the area search server 2 starts the next area from the leaf node of the index including the vicinity of the area in which the previous position can be searched. By performing the search, the search time for the area search including the next position can be increased.

[Comparison result of area search frequency]
Here, a comparison result of the number of search times of the area search when the search is started from the root node and when the search is started from the area that has been searched last time will be described with reference to FIG. FIG. 23 is a diagram for explaining a comparison result of the number of searches. As shown in FIG. 23, the R-tree is an index tree having a depth of 5. The root node R0 is a rectangular area including all rectangular areas such as the node R1 having a depth of 1. The node R1 is a rectangular area including all rectangular areas such as the node R2 having a depth of 2. The node R2 is a rectangular area including all rectangular areas such as the node R3 having a depth of 3. The node R3 is a rectangular area including all the rectangular areas of the nodes RA and RB having a depth of 4. The node RA includes area data of A1, A2, and A3. The node RB includes region data of B1, B2, and B3. A2 is an overlapping area overlapping with A1, A3, and B1. A3 is an overlapping area overlapping with A1, A2, and B1.

First, as a result of the area search of the area search request including the position of P2 first, the area search server 2 records A2 as the previous search area in the previous position DB 201 among the area data A2 and B1 including the position of P2. Shall be. Then, it is assumed that the area search server 2 performs the area search of the area search request including the position of P3 next time. Then, the number of searches N1 performed by the area search server 2 is as follows.
N1 = 1 (A2) +3 (overlapping area of A2) = 4
That is, N1 searches once whether the position of P3 is included in the area of A2, and since the position of P3 is included in the area of A2, overlapping areas A1, A3, B1 overlapping with the area of A2 The value 4 is obtained by adding 3 times to search whether or not the position of P3 is included.

On the other hand, when the search is started from the root node, the search count O1 is as follows. It is assumed that the child node of each node is 3.
O1 = 4 × 3 (R0 to R3) +3 (RA) +3 (RB) = 18
That is, 12 times for searching whether each node includes the position of P3 by the number of child nodes (3) for the four nodes R0 to R3 is set in O1. Furthermore, since the position of P3 is included in RA and RB, 15 times obtained by adding 3 times for searching whether the position of P3 is included in the three area data included in RA to O1 is set. . Furthermore, 18 times obtained by adding 3 times for searching whether the position of P3 is included in the 3 area data included in the RB to O1 is set.

As a result of the area search server 2 performing the next area search, it is assumed that A2 of the area data A1, A2, A3, B1 including the position of P3 is recorded in the previous position DB 201 as the previous search area. Then, it is assumed that the area search server 2 performs the area search of the area search request including the position of P4 next time. Then, the number of searches N2 performed by the area search server 2 is as follows.
N2 = 1 (A2) +3 (RA) +3 (overlapping area of A3) = 7
That is, N2 is set once to search whether the position of P4 is included in the area of A2. Further, since the position of P4 is not included in the area of A2, four times obtained by adding 3 times to search for whether the position of P4 is included in the three area data included in the node RA of A2 are added to N2. Is set. Furthermore, since the position of P4 is included in the area of A3, 7 times of adding 3 to the search for whether the position of P4 is included in the overlapping areas A1, A2, and B1 overlapping with the area of A3 is added to N2. Is set. On the other hand, when the search is started from the root node, the number of searches is O1, that is, 18 times.

  In this way, the area search server 2 can perform the next area search from the previous search area so that the number of area searches including the next position can be less than the number of searches when the search is started from the root node, Search time can be increased.

  Note that, as a modification of the processing of the overlapping area setting unit 135, when the number of overlapping areas overlapping with the additional area is a predetermined number or more, the overlapping area is not added to the overlapping area column of the additional area. However, the overlapping area setting unit 135 is not limited to this, and when the number of overlapping areas overlapping with the additional area is equal to or greater than a predetermined number, the overlap area column of the additional area indicates “excessive number of overlapping areas”. Information may be added.

  Further, the previous position DB 201 has been described as associating the sensor ID 201a with the previous search area 201. However, in the previous position DB 201, the sensor ID 201a may be replaced with, for example, the device ID of the terminal device that requests the area search, or may be replaced with the mobile phone number of the mobile phone that requests the area search. That is, the ID corresponding to the sensor ID 201a can be changed for each use case.

  Moreover, even if the search coordinates (position information) are not included in the region data at all, if there is a node including the search coordinates, the tree search unit 133 sets the deepest node (deepest node) among the nodes as the previous position. Recorded in DB201. Here, there may be a plurality of deepest nodes at the same depth. In such a case, the tree search unit 133 may record, for example, the deepest node having the smallest number of child nodes for each deepest node in the previous position DB 201. In another example, the tree search unit 133 records the deepest node having the smallest number of child nodes per area of the rectangular area for each deepest node in the previous position DB 201. Specifically, the tree search unit 133 calculates, for each deepest node, a value obtained by dividing the number of child nodes in the child node list by the area of the rectangular area, selects the deepest node with the smallest calculated value, and selects The deepest node is recorded in the previous position DB 201. In other words, it is desirable for the node to have a small amount of next search.

[Programs]
The area search servers 1 and 2 can be realized by mounting each function such as the tree search unit 133 and the duplicate data search unit 134 on an information processing apparatus such as a known personal computer or workstation. .

  In addition, each component of each illustrated apparatus does not necessarily need to be physically configured as illustrated. That is, the specific mode of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. For example, the tree search unit 133 and the duplicate data search unit 134 may be integrated as one unit. On the other hand, the tree search unit 133 may be distributed to search processing in leaf nodes and search processing in nodes other than leaf nodes. Further, a storage unit such as the region data DB 122 may be connected as an external device of the region search servers 1 and 2 via a network.

  The various processes described in the above embodiments can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. Therefore, in the following, an example of a computer that executes an area search program that implements the same function as the area search server 1 illustrated in FIG. 1 will be described. FIG. 24 is a diagram illustrating an example of a computer that executes an area search program.

  As illustrated in FIG. 24, the computer 200 includes a CPU 201 that executes various arithmetic processes, an input device 202 that receives input of data from a user, and a display 203. The computer 200 also includes a reading device 204 that reads a program and the like from a storage medium, and an interface device 205 that exchanges data with other computers via a network. The computer 200 also includes a RAM 206 that temporarily stores various information and a hard disk device 207. The devices 201 to 207 are connected to the bus 208.

  The hard disk device 207 stores an area search program 207a and an overlapping area setting program 207b. The CPU 201 reads out each program 207 a-207 b and develops it in the RAM 206. The area search program 207a functions as an area search process 206a. The overlapping area setting program 207b functions as an overlapping area setting process 206b.

  For example, the area search process 206 a corresponds to the tree search unit 133 and the duplicate data search unit 134. The overlapping area setting process 206 b corresponds to the overlapping area setting unit 135.

  Note that the programs 207a to 207b are not necessarily stored in the hard disk device 207 from the beginning. For example, each program is stored in a “portable physical medium” such as a flexible disk (FD), a CD-ROM, a DVD disk, a magneto-optical disk, and an IC card inserted into the computer 200. Then, the computer 200 may read and execute each of the programs 207a to 207b from these.

  The following appendices are further disclosed with respect to the embodiments including Examples 1 and 2 described above.

(Supplementary Note 1) Index information used when a computer searches for an area and including index information for managing the area together with area information including a plurality of areas, using an index tree representing a predetermined position, Search for the containing area,
When the area including the position can be searched, the area including the position is selected from the overlapping areas of the searched areas based on the storage unit storing the information of the overlapping area overlapping the area for each of the plurality of areas. Search and
An area search method that outputs information on areas that can be searched.

(Supplementary Note 2) When an inquiry request for an area including a predetermined position is acquired, it is determined whether or not the position is included in the area that was previously searched,
As a result of the determination, when it is determined that the position is included in the area that can be searched last time, an area including the position is searched from the overlapping areas determined to be included based on the storage unit. The region search method according to appendix 1, characterized by:

(Supplementary Note 3) When it is determined that the position is not included in the previously searched area as a result of the determination, the index information includes the area determined not to be included in the nodes forming the tree structure. Search the area containing the position from the leaf node,
The area search method according to appendix 2, wherein when the area including the position can be searched, the area including the position is searched from the overlapping areas of the searched information.

(Additional remark 4) In the process which searches the said area | region, when there are two or more areas which were able to be searched, the area | region with the smallest number of overlapping areas is selected from several areas, The additional remark 2 or the additional remark 3 characterized by the above-mentioned Area search method.

(Supplementary note 5) The region search method according to supplementary note 1, wherein the process of storing in the storage unit does not store the information of the overlapping region relating to the region when the overlapping region overlapping the region exceeds a predetermined value .

(Appendix 6)
Using the index tree that represents the index information used when searching for the area and the area information including a plurality of areas and the index information for managing the area in a tree structure, the area including the predetermined position is searched,
When the area including the position can be searched, the area including the position is selected from the overlapping areas of the searched areas based on the storage unit storing the information of the overlapping area overlapping the area for each of the plurality of areas. Search and
An area search program that outputs information on areas that can be searched and that executes each process.

(Additional remark 7) The memory | storage part which memorize | stored the information of the overlapping area which overlaps with an area | region about each of several area | region,
The index information used when searching for an area, and using the index tree representing the index information for managing the area in a tree structure together with the area information including a plurality of areas, the area including the predetermined position is searched. 1 search part,
A second search unit that searches for an area including the position from among the overlapping areas of the areas that can be searched based on the storage unit when the first search unit can search the area including the position;
An information processing apparatus comprising: an output unit that outputs information on an area that can be searched by the first search unit and the second search unit.

1, 2 area search server 11 communication interface 12 storage unit 121 area index DB
122 Area data DB
DESCRIPTION OF SYMBOLS 13 Control part 131 Request reception part 132 Response transfer part 133 Tree search part 134 Duplicate data search part 135 Duplicate area setting part 201 Previous position DB
202 Previous area search unit 203 Previous area recording unit

Claims (6)

A search is made for an area including a predetermined position by using an index tree which is index information used when a computer searches for an area and which includes a plurality of areas and index information for managing the area in a tree structure. And
When the area including the position can be searched, the search can be performed based on the storage unit storing the information of the overlapping area indicating the other area when a part of the plurality of areas overlaps with the other area . Search for the area containing the position from the overlapping areas that overlap with the area,
An area search method that outputs information on areas that can be searched. When an inquiry request for an area including a predetermined position is acquired, it is determined whether or not the position is included in the area that was previously searched,
As a result of the determination, when it is determined that the position is included in the area that can be searched last time, an area including the position is searched from the overlapping areas determined to be included based on the storage unit. The region search method according to claim 1. As a result of the determination, when it is determined that the position is not included in the area that was previously searched, from the leaf nodes of the index information including the area determined not to be included among the nodes that form the tree structure Search for the area containing the position,
3. The area search method according to claim 2, wherein, when an area including the position can be searched, an area including the position is searched from an overlapping area of the searched information.   4. The region according to claim 2, wherein when there are a plurality of regions that can be searched in the process of searching for the region, the region having the smallest number of overlapping regions is selected from the plurality of regions. retrieval method. On the computer,
Using the index tree that represents the index information used when searching for the area and the area information including a plurality of areas and the index information for managing the area in a tree structure, the area including the predetermined position is searched,
When the area including the position can be searched, the search can be performed based on the storage unit storing the information of the overlapping area indicating the other area when a part of the plurality of areas overlaps with the other area . Search for the area containing the position from the overlapping areas that overlap with the area,
An area search program that outputs information on areas that can be searched and that executes each process. A storage unit that stores information on an overlapping area indicating the other area when a part of each of the plurality of areas overlaps with another area ;
The index information used when searching for an area, and using the index tree representing the index information for managing the area in a tree structure together with the area information including a plurality of areas, the area including the predetermined position is searched. 1 search part,
A second search unit that searches for an area including the position from an overlapping area that overlaps the searched area based on the storage unit when the first search unit can search the area including the position; When,
An information processing apparatus comprising: an output unit that outputs information on an area that can be searched by the first search unit and the second search unit.

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