JP2012256120A - Information processing device and method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology to reduce a processing load in searching geographical information.SOLUTION: An information processing device comprises: map data preservation means; interest position acquisition means that acquires the geographic code of a position of interest indicating a position to be searched in map data; candidate acquisition means that acquires, as candidates of search results, one or a plurality of meshes having the character string of a geographical code according with that of a geographical code of a position of interest in a mesh group covering an area to be searched that indicates a range searched in map data; exclusion means that determines whether meshes, not completely included in the area to be searched, in one or a plurality of meshes acquired as candidates of search results include the position of interest, and that excludes one or a plurality of meshes that do not include the position of interest from the mesh group; and output means that outputs one or a plurality of meshes as search results after the exclusion job on search results is performed.

Description

  The present invention relates to an information processing apparatus, a processing method thereof, and a program.

  In recent years, storage and recording media have been increased in capacity, and even a relatively small device handles a large amount of accumulated data, and a search function is becoming essential.

  For example, in flash media in which photographed photos and the like are stored in a camera, an SDXC standard card having a capacity of 64 GB is currently on the market, and 60,000 or more photos of 1 MB each are stored. The SDXC standard can be expanded up to 2 TB.

  In order to obtain a target photograph from a large number of photographs, the conventional browsing function in the order of photographing is not sufficient, and it is necessary to be able to retrieve photographs from various viewpoints. One of the search methods is metadata search. For example, if a photo address and landmark metadata are assigned to the photo, the photo can be searched from the address and landmark information. For this purpose, a function for adding metadata to a photograph is required.

  In recent years, a GPS function has been installed in a camera, and it has become possible to give a photograph geographic information that can be used to identify the latitude and longitude of a shooting location. There is a need for a geographic information search in which a dictionary of geographic areas indicated by addresses and landmarks is built in the camera, and a geographic area including a shooting point is searched based on latitude / longitude information.

  The geographic information search includes a range specification search for searching for data of points included in a specified range, a k nearest neighbor search for searching k pieces of data of points that are spatially close to a specified position in ascending order.

  There are many methods for realizing range-designated search. A famous method is R-tree. R-tree is a method of performing a high-speed search by collecting a plurality of spatially neighboring regions to obtain a minimum bounding rectangle (MBR) and holding it in an index. If there are many groups of areas, create a group of more than one to make the index hierarchical.

  There are also many ways to realize k nearest neighbor search. Patent Document 1 mentions a technique for searching for a predetermined number of points near a designated point. More specifically, the distance between the point included in the small area group and the specified point is calculated one by one with the small area including the specified point and the small area adjacent to the small area as the search target small area group, A predetermined number of search results are obtained from nearby points.

  In addition, a method of encoding latitude / longitude coordinates into a character string has been proposed (see Patent Document 2). In this method, an integer is converted from a coordinate value (floating point number) of latitude / longitude, a character string is converted from an integer, and a character string converted from both latitude and longitude is connected and encoded. In another proposal, a method of encoding integer numbers of latitude and longitude information alternately by one bit at a time and encoding it into a character string, or using this encoding method to search for a point in a specified area A method has also been proposed.

JP 2003-242151 A US Patent Application Publication No. 2005/0023524

  The R-tree method is a method for holding and controlling a dedicated index mechanism that is different from an index for character string search. In particular, a processing load increases for a device having a low processing capability (for example, an embedded device). .

  In addition, the method disclosed in Patent Document 1 can only search for a point close to the designated point. Therefore, a point where the designated point is included in an indefinite area such as an address or a landmark is added. You can't search.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique that reduces the processing load when performing geographic information search.

  In order to solve the above-described problem, an information processing apparatus according to an aspect of the present invention expresses a high-order mesh in which a ground surface is hierarchically divided into meshes, and a geographical code indicating a position of each mesh is represented by a character string. A holding means for holding map data having a geographic code system indicating a geographic code of a lower mesh by adding characters to the geographic code to be acquired, and a geographic code of a point of interest indicating a point to be searched on the map data are acquired 1 having a character string of a geographic code that matches a character string of a geographic code indicating the point of interest, out of a mesh group covering a search target area indicating a range to be searched on the map data Among candidate acquisition means for acquiring a plurality of meshes as search result candidates, and one or a plurality of meshes acquired as search result candidates, Exclusion that determines whether or not the point of interest is included in a mesh that is not completely included in the search target region, and excludes one or more meshes that do not include the point of interest from the mesh group Means and output means for outputting one or more meshes after the exclusion from the search result candidates as a search result.

  According to the present invention, it is possible to reduce the processing load when performing geographic information search.

The figure which shows an example of a structure of the information processing apparatus 10 which concerns on one embodiment of this invention. The figure which shows the outline | summary of the process at the time of performing geographic information search. The figure which shows an example of the map data which concern on this embodiment. The figure which shows an example of the mesh which covers a search object area | region. The figure which shows an example of a structure of the tables 41-43. 3 is a flowchart illustrating an example of a processing flow of the information processing apparatus 10 illustrated in FIG. 1. 7 is a flowchart showing an example of a flow of area search processing shown in S104 of FIG. 7 is a flowchart showing an example of the flow of area registration processing shown in S105 of FIG. The figure which shows an example of a modification.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing an example of the configuration of an information processing apparatus 10 according to an embodiment of the present invention.

  The information processing apparatus 10 includes a CPU 11, an input unit 12, an output unit 13, an imaging unit 14, a communication unit 15, a bus 16, a ROM 17, a RAM 18, and an external storage medium 19. The

  A CPU (Central Processing Unit) 11 performs overall control of processing in the information processing apparatus 10 according to a program stored in the ROM 17, for example. In the CPU 11, for example, a search process, an area registration process, a screen control process, a calculation for a photographing process, a logical determination, and the like are performed, and each device connected to the bus via the bus 16 is controlled.

  The bus 16 transfers address signals, control signals, and the like. Data transfer between devices is also performed.

  The input unit 12 is realized by, for example, a button or a touch panel, and inputs various instructions from the user into the apparatus. The output unit 13 is realized by a liquid crystal display or the like, and outputs (displays) various types of information to the user. Note that the output by the output unit 13 may be realized by printing or may be realized by voice, for example.

  The imaging unit 14 is realized by an imaging sensor or the like, for example, and reads an image and converts it into electronic data. The communication unit 15 is realized by a network controller or the like, for example, and exchanges data with an external device via a wired or wireless communication path.

  A ROM (Read Only Memory) 17 is a nonvolatile memory. In addition to various programs executed by the CPU 11 (boot program 21, system control program 22), various initial data 23, map data 24, and the like referred to in various processes are stored.

  A RAM (Random Access Memory) 18 is a readable / writable memory. The RAM 18 is used for primary storage of various data from each device. The RAM 18 stores a stack 32 and the like in addition to various work areas 31.

  The external storage medium 19 is realized by a flash medium such as an SD card or a CF card, for example. The external storage medium 19 is a large-capacity non-volatile memory that can be erased collectively in block units, and stores a large amount of data in a changeable manner. The external storage medium 19 is not limited to the above-described card or the like, and can be replaced with a hard disk or the like. The external storage medium 19 stores a mesh table 41, a detailed index table 42, an area table 43, and the like, and the contents are corrected as needed.

  Here, in the CPU 11, “☆” and “☆” are realized as functional configurations. These configurations are realized, for example, by the CPU 11 executing a program stored in the ROM 17 or the like.

  The area registration unit 50 registers an area to be searched (search target area). The search target area is designated by a user instruction via the input unit 12, for example.

  The point of interest acquisition unit 51 acquires the point of interest (the mesh code). The point of interest indicates a point on the map data to be searched. Although details will be described later, in the map data according to the present embodiment, the ground surface is hierarchically divided into meshes. In addition, a geographic code indicating the position of each mesh is represented by a character string. The lower mesh is expressed by adding characters to the geographic code expressing the upper mesh.

  The search unit 52 performs a function of searching for a predetermined mesh by comparing a character string of a geographical code indicating a point of interest with a character string of a geographical code of a mesh group that covers a search target region. And an exclusion unit 62. The candidate acquisition unit 61 acquires one or more meshes including the point of interest as a search result candidate from the mesh group covering the search target region. The exclusion unit 62 excludes any mesh from the mesh search result candidates according to a predetermined condition.

  The above is the description of the functional configuration of the information processing apparatus 10. In the present embodiment, a case where the information processing apparatus 10 is applied to an imaging apparatus (for example, a digital camera or a digital video camera) having the imaging unit 14 will be described, but the present invention is not limited thereto. The information processing device 10 may be applied as an embedded device to various devices such as a communication device and an image display device.

  In the above description, the case where various processes are executed by the CPU 11 executing a program has been described. However, the present invention is not limited to this. For example, a control circuit such as an ASIC that operates in cooperation with the CPU performs various processes. May be executed. Various processes may be executed by cooperative operation of the CPU and the control circuit. Moreover, the CPU does not need to be single, and may be plural. In this case, a plurality of CPUs execute processing in a distributed manner. Further, the plurality of CPUs may be arranged in a single computer, or may be arranged in a plurality of physically different computers. Note that the processing realized by the CPU executing the program may be realized by a dedicated circuit.

  Next, the outline of processing when performing geographic information search for searching for an area including a point will be described with reference to FIG.

  Here, a case where a region including the point of interest 201 is searched will be described. In this case, the search target areas 203 and 206 including the point of interest 201 are hit as a result of the search. On the other hand, the search target areas 202, 204, and 205 do not hit because they do not include the point of interest 201.

  Here, attention is focused on the relationship between the region 203 and the region 204. That is, it should be noted that although the center of the region 203 is far from the center of the region 204, the far region 203 hits and the near region 204 does not hit. Such a search is indispensable when place name metadata is added to a photo. For example, a photo taken near “Hiroo” may not be given “Roppongi”, which is close to the center, but may be given “Tokyo”, which is the name of a wide area that is far from the center.

  Next, map data according to the present embodiment will be described with reference to FIGS. 3 (a) and 3 (b). In the present embodiment, the map data has a geographic code system in which the ground surface is divided by a hierarchical mesh and the position of the mesh is expressed by a geographic code based on latitude / longitude information. The geographic code is represented by a character string.

  First, an example of processing for converting latitude / longitude information into a geographic code will be described with reference to FIG.

  When converting latitude / route information into a geographic code, first, the ground surface is divided into two along the direction of latitude or longitude, and a bit of 0 or 1 is assigned to the divided ground surface for each division. For each of latitude and longitude, the bit is arranged in order from the large division to create a bit string, and the bit string is used as latitude information 301 and longitude information 302 of the mesh. The bit string generated in this way is selected one bit at a time from the top in the order of longitude and latitude, and a bit string 303 is generated. The bit string 303 is divided into 5 bits from the beginning, and the bit string is converted into a character code in units of 5 bits according to the conversion table 304. Thereby, the geographic code 305 is obtained.

  Each mesh is hierarchically detailed according to the number of divisions of the ground surface. As the mesh is refined, the number of bits of latitude / longitude information increases, and the number of characters in the converted character string also increases. Therefore, since the number of characters represents the accuracy of the mesh, the accuracy of the mesh can be defined as the number of characters in the character string. The mesh geographic code generated in this way is called a mesh code.

  Next, an example of a hierarchical structure formed by the mesh will be described with reference to FIG.

  A mesh 306 indicates a mesh expressed by “e” with accuracy = 1 (that is, the number of characters = 1). By adding one character in the mesh 306 to “e”, it can be divided into 32 sub-mesh.

  When the next one character is “7”, the mesh 307 with accuracy = 2 is obtained, and the mesh code is “e7”. An enlarged view of the mesh 307 is a mesh 308. In this case as well, it can be divided into 32 sub-mesh by adding the next character.

  When the next one character is “s”, the mesh 309 with accuracy = 3 is obtained, and the mesh code is “e7s”. That is, it is understood that the mesh is hierarchized according to the number of characters of the mesh code. It indicates whether or not the number of characters of the mesh code belongs to the same hierarchy.

  Here, the table 310 shows an example of the approximate area of the geographical area represented by the mesh layered in this way. According to Table 310, it is shown that a mesh with accuracy = 3 represents a rectangular area of 156 km × 156 km. In addition, it can be seen that if the accuracy is increased, a more detailed geographical area is expressed. For example, a mesh code with an accuracy of 12 can effectively represent a specific point on the map data. In this embodiment, when a point is specified, it is expressed by a mesh code with the most detailed accuracy on the system.

  Next, an example of a mesh covering the search target area will be described with reference to FIG.

  Here, reference numeral 401 indicates a search target area. Meshes covering this region 401 are shown as mesh 1 to mesh 17. Each mesh may belong to a different hierarchy. For example, the mesh 8 has a larger area than the other meshes because this is a higher-order mesh in which a plurality of lower-order meshes are integrated and the hierarchy is increased by one stage.

  Here, when a search is performed using a point 402 indicated by a black circle as a point of interest, the region 401 becomes a hit region. When a search is performed using a point 403 indicated by a cross as a point of interest, the region 401 is not a hit region. Here, among meshes, a mesh that is completely included in the search target area (for example, reference numeral 404) is called a complete inclusion mesh, and a mesh that is partially included in the search target area (for example, reference numeral 405) is a part. This is called an inclusion mesh.

  When the point 403 is the point of interest, the mesh 6 is hit when the search target area 401 is searched based on the mesh group. However, the mesh 6 is a partial inclusion mesh, and the point 403 is outside the region 401. Therefore, in the detailed check performed thereafter, it is found that the point 403 is not included in the region 401, and the mesh 6 is excluded from the search result. Such a detailed check eventually deviates from the search result, but a search result that is a candidate for the search result in the middle of processing is called a “false search result”.

  Next, an example of the configuration of the mesh table 41, the detailed index table 42, and the area table 43 will be described with reference to FIG.

  The mesh table 41 manages a mesh group covering the search target area. A column 502 holds a mesh code of each mesh. The column 503 holds the ID of the search target area. By referring to the area table 43 using this ID, detailed information on the area is obtained. A column 504 holds a flag (referred to as “complete flag”) indicating whether or not the search target region completely includes the region of each mesh. When completely included (referred to as “completely included”), “1” is retained, and when partially included (referred to as “partially included”), “0” is retained. A column 505 holds a link to a detailed index table 42 that manages a mesh group that further refines the mesh of the partial inclusion. That is, in the mesh table 41, the search target area, the complete flag, and the link to the detailed index table 42 are managed in association with each other.

  The area table 43 manages the geographical range of the search target area. Here, the description will be made on the assumption that the region is formed of a rectangle. A column 507 holds the ID of the search target area. A column 508 holds a mesh code at the upper left point of the search target area. A column 509 holds a mesh code at the lower right point of the search target area.

  The detailed index table 42 manages a mesh group in which the partial inclusion mesh is subdivided into meshes in a lower layer and detailed. A column 511 holds a mesh code of a detailed mesh. The column 512 holds the ID of the search target area corresponding to the mesh.

  Here, the above-described processing will be described using a flowchart. FIG. 6 is a diagram illustrating an example of a flow of processing in the information processing apparatus 10 illustrated in FIG. This process is realized, for example, when the CPU 11 reads and executes a program stored in the ROM 17.

  In this process, the information processing apparatus 10 first performs a system initialization process in the CPU 11 (S101). That is, various parameters are initialized and an initial screen is displayed.

  Thereafter, the information processing apparatus 10 waits until an event occurs from the input unit 12 such as a touch panel in the CPU 11 (S102). When an event occurs, the information processing apparatus 10 determines this event in the CPU 11 and branches to various processes according to the type of event.

  If the event indicates an area search process (area search in S103), the information processing apparatus 10 performs the area search process according to the event (S104). If the event indicates an area registration process (area registration in S103), the information processing apparatus 10 performs the area registration process according to the event (S105). If it is any other event (other event in S103), the information processing apparatus 10 performs processing corresponding to various events (S106). Other events include screen control processing, photography processing, and the like.

  Thereafter, the information processing apparatus 10 outputs the processing result of each process to the user at the output unit 13. For example, a search result is displayed, an error is displayed when there is an error, and a screen is displayed when normal processing is performed.

  Next, an example of the flow of the area search process shown in S104 of FIG. 6 will be described using FIG. That is, a process for searching for a geographic area (one or a plurality of meshes) including a point of interest in the search target area will be described.

  When this process starts, the information processing apparatus 10 first acquires a point of interest in the point of interest acquisition unit 51 (S201). That is, a mesh code indicating the point of interest is acquired. The point of interest is specified by a user instruction via the input unit 12, for example.

  Subsequently, in the information processing apparatus 10, the candidate acquisition unit 61 acquires search result candidates using the mesh code acquired in the process of S201 as a search character string (S202, S203). That is, a mesh having a mesh code that matches at least a part of the search character string (front character string) is searched from the mesh table 41, and is used as a search result candidate.

  In the information processing apparatus 10, the exclusion unit 62 checks the complete flag of the mesh acquired as a search result candidate. That is, it is determined whether each mesh is a complete inclusion mesh or a partial inclusion mesh.

  As a result of the determination, if it is a complete inclusion mesh (YES in S204), the information processing apparatus 10 proceeds to the process of S208. On the other hand, if it is a partial inclusion mesh (NO in S204), the information processing apparatus 10 performs a detailed check of the positional relationship between the point of interest and the search target area in the exclusion unit 62 (S205). That is, it is checked whether or not the point of interest included in the mesh acquired in the process of S203 is within the search target area. In this check, first, a mesh group in a lower hierarchy of the corresponding mesh is acquired from the detailed index table 42, and a mesh including the point of interest is acquired from the mesh group. Then, it is determined whether or not the mesh is included in the search target area. Thereby, if it is not included in the search target area, the mesh searched in the process of S203 is determined to be a fake search result.

  As a result of the detailed check, if the point of interest is not included, that is, if it is a fake search result (YES in S206), the information processing apparatus 10 excludes the fake search result in the exclusion unit 62 (S207), and then S208. Proceed to the process. That is, the mesh that is the false search result is excluded.

  On the other hand, if the result is not a fake search result (NO in S206), the information processing apparatus 10 deletes one character at the end of the search character string in the search unit 52 (S208). That is, the mesh hierarchy at the point of interest is raised to a wide area by one step. As a result, a broader mesh in which the front character string of the mesh code at the point of interest matches the mesh code can be acquired from the mesh table 41.

  The information processing apparatus 10 determines in the search unit 52 whether the length of the search character string has become “0” as a result of the deletion of one character. If the length of the character string is not “0” (NO in S209), the information processing apparatus 10 performs the process of S203 again in order to perform a broader mesh forward match search. That is, the processes of S203 to S208 are repeated until the length of the character string becomes “0”.

  On the other hand, if the length of the character is “0” (YES in S209), the information processing apparatus 10 outputs the search result candidates acquired so far as an official search result in the output unit 13 ( S210), this process is terminated.

  Next, an example of the flow of area registration processing shown in S105 of FIG. 6 will be described using FIG. That is, a process for registering an area to be a search target area will be described.

  When this processing starts, the information processing apparatus 10 first registers the specified area in the area table 43 as a search target area in the area registration unit 50 (S301). The search target area is designated by a user instruction via the input unit 12, for example. The information processing apparatus 10 obtains a mesh group covering the search target area in the area registration unit 50 (S302).

  In the area registration unit 50, the information processing apparatus 10 registers the mesh group obtained in the process of S302 in the mesh table 41 (S303), and determines whether or not there is a partial inclusion mesh in the mesh group. .

  As a result of the determination, if there is no partial inclusion mesh (NO in S304), the information processing apparatus 10 ends this process. If there is a partial inclusion mesh (YES in S304), the information processing apparatus 10 subdivides (i.e., refines) the mesh into a lower layer mesh in the region registration unit 50 (S305). Then, after the subdivided mesh group is registered in the detailed index table 42 (S306), this process ends.

  As described above, according to the present embodiment, a normal character string search index mechanism is used to perform a forward matching search, thereby reducing a processing load when searching for a search target region including a point of interest. it can. Furthermore, by providing a detailed index table in which the partial inclusion mesh is detailed, the detailed check process can be further accelerated.

  Note that when searching for geographic information based on latitude / longitude in the conventional technology, a dedicated index having a different structure from the text search index is required. Was big.

(Embodiment 2)
Next, Embodiment 2 will be described. In the above-described first embodiment, the case where the search target area 401 has a rectangular shape has been described. However, the present invention is not limited to this. In the second embodiment, as an example of the shape of the search target area, a case where the area is circular will be described. For example, as shown in FIG. 9A, the search target area 406 may be circular. In this case as well, there are the complete inclusion mesh 6 (reference numeral 407) and the partial inclusion mesh 12 (reference numeral 408).

  FIG. 9B shows an example of the configuration of the mesh table 41 and the region table 43 linked from the mesh table 41 when the search target region 406 is circular. The mesh table 41 has the same configuration as that shown in FIG.

  The area table 43 manages a circular search target area 406. A column 515 holds the ID of the search target area. A column 516 holds a mesh code at the center point of the search target area (circle). Column 517 holds the radial distance of the circle.

  Further, in the detailed check in S205 of FIG. 7 described in the first embodiment, the distance from the center of the search target area that is circular to the point of interest is obtained, and whether or not it is equal to or less than the radius is compared. Perform a detailed check with. With this configuration, even when the search target area is circular, the same processing as in the first embodiment can be performed.

  The above is an example of a typical embodiment of the present invention, but the present invention is not limited to the embodiment described above and shown in the drawings, and can be appropriately modified and implemented without departing from the scope of the present invention. .

  In addition, the present invention can take an embodiment as a system, apparatus, method, program, storage medium, or the like. Specifically, the present invention may be applied to a system composed of a plurality of devices, or may be applied to an apparatus composed of a single device.

(Other embodiments)
The present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

Claims (5)

The ground surface is hierarchically divided into meshes, the geo codes indicating the positions of the meshes are represented by character strings, and the geo codes representing the lower meshes are added by adding characters to the geo codes representing the upper meshes. Holding means for holding map data having a code system;
Point-of-interest acquisition means for acquiring a geographical code of a point of interest indicating a point to be searched on the map data;
One or more meshes having a character string of a geographic code that matches a character string of a geographic code indicating the point of interest among mesh groups covering a search target area indicating a range to be searched on the map data. Candidate acquisition means for acquiring as candidates,
It is determined whether or not the target point is included in a mesh that is not completely included in the search target region among one or a plurality of meshes acquired as candidates for the search result, and the target point is Exclusion means for excluding one or more meshes not included from the mesh group;
And an output unit that outputs one or a plurality of meshes after the exclusion from the search result candidates as a search result. The candidate acquisition means includes
Until the length of the character string of the geographic code indicating the point of interest is 0, the character string is deleted character by character and the search using the character string of the geographic code indicating the point of interest is repeated.
The exclusion means includes
The exclusion is repeated each time the candidate acquisition unit performs a search,
The output means includes
The information processing apparatus according to claim 1, wherein when the length of the character string of the geographic code becomes 0, a search result acquired so far is output. A mesh table for managing a character string of each geographic code covering the search target area in association with information indicating whether or not the search target area is completely included, and
A detailed index table for managing information on meshes in lower layers of meshes that are not completely included in the search target region, among mesh groups managed in the mesh table;
The candidate acquisition means includes
Use the mesh table to obtain the search result candidates,
The exclusion means includes
The information processing apparatus according to claim 1, wherein the exclusion is performed using the detailed index table. A processing method for an information processing apparatus,
The acquisition means is configured such that the ground surface is hierarchically divided into meshes, the geo codes indicating the positions of the meshes are represented by character strings, and the geometries of the lower meshes are added by adding characters to the geo codes representing the upper meshes. Obtaining map data having a geographic code system indicating a code;
A step of acquiring a point-of-interest geographical code indicating a point to be searched on the map data;
The candidate acquisition means has one or more character strings having a geographic code that matches the character string of the geographic code indicating the point of interest in the mesh group covering the search target area indicating the search range on the map data. Obtaining a mesh as a search result candidate;
It is determined whether or not the exclusion means includes the point of interest with respect to a mesh that is not completely included in the search target region among one or a plurality of meshes acquired as candidates for the search result, A step of excluding one or more meshes that do not contain the point of interest from the mesh group;
And an output means for outputting one or a plurality of meshes after the exclusion from the search result candidates as a search result. Computer
The ground surface is hierarchically divided into meshes, the geo codes indicating the positions of the meshes are represented by character strings, and the geo codes representing the lower meshes are added by adding characters to the geo codes representing the upper meshes. Holding means for holding map data having a code system;
Point-of-interest acquisition means for acquiring a geographic code of a point of interest indicating a point to be searched on the map data;
One or more meshes having a character string of a geographic code that matches a character string of a geographic code indicating the point of interest among mesh groups covering a search target area indicating a range to be searched on the map data. Candidate acquisition means for acquiring as candidates,
It is determined whether or not the target point is included in a mesh that is not completely included in the search target region among one or a plurality of meshes acquired as candidates for the search result, and the target point is Excluding means for excluding one or more meshes not included from the mesh group,
A program for functioning as output means for outputting one or a plurality of meshes after the exclusion from the search result candidates as a search result.

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