JP2009093384A - Poi search system, route search server and poi search method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the load of POI search, and to quickly provide the proper number of pieces of POI information. <P>SOLUTION: This POI search system is provided with: a rectangular area determination table 372 in which area determination data for determining a rectangular area with a prescribed area are set for each prescribed area and a threshold table 371 in which a threshold has been set, the threshold being for selecting the rectangular area according to the number of POIs searched by a POI search means 33. A rectangular area determination means 37 discriminates whether or not it is necessary to change the rectangular area by referring to the threshold table 371 and the rectangular area determination table 372 based on the number of POIs searched by the POI search means 33, and when it is necessary to change the rectangular area, the rectangular area determination means 37 acquires the pertinent rectangular area determination data by referring to the threshold table 371 and the rectangular area determination table 372, and changes the area of the rectangular area based on the acquired rectangular area determination data, and the POI search means 33 searches the POI in the changed rectangular area, and sorts the search result by a sorting means 331, and displays it at a display means 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a POI search system for searching for a desired POI (Point of Interest) located in a predetermined area and providing facility information, and in particular, a current position of a terminal device Further, the present invention relates to a POI search system that determines a predetermined rectangular area around a specific point, searches for a POI located in the area, and provides POI information related to a desired POI.

  2. Description of the Related Art Conventionally, navigation devices and navigation systems that guide a user by searching for a route from a desired departure point to a destination using map data and road data are known. Such navigation devices and navigation systems are known. As a car navigation device that is installed in an automobile and guides the route to the driver, a communication type that uses a mobile phone as a navigation terminal to send a route search request to the route search server, receives the result, and receives route guidance Navigation systems have been put to practical use.

  In particular, the communication-type navigation system is a system that uses a mobile terminal such as a mobile phone as a navigation terminal, and is also used as a navigation system for pedestrians. As a navigation system for pedestrians, it is preferable to add a route guidance function including transportation, and in addition to searching and guidance for walking routes, the route search server accumulates routes and operation time data of transportation, There is also a navigation system having a function of guiding a route from a desired departure station to a desired destination station (boarding candidate train) in addition to searching for a walking route and guidance. There is also a traffic guidance system that receives and displays information such as routes, timetables of transportation facilities, and trains that can be boarded from an information distribution server without searching for walking routes.

  A general navigation device, a route search device and a route search method used in a communication navigation system are disclosed in, for example, the following Patent Document 1 (Japanese Patent Laid-Open No. 2001-165681). This navigation system is configured to send information on a departure point and a destination from a portable navigation terminal to an information distribution server, and the information distribution server searches and guides a route that matches a search condition from road network and traffic network data. Has been. As the search condition, there are means for moving from the departure place to the destination, for example, walking, automobile, combined use of railroad and walking, and the route is searched as one of the search conditions.

  The information distribution server has roads (routes) of map data as nodes and nodes as the positions of inflection points, links connecting the nodes as links, and cost information (distance and required time) of all links as a database. ing. Then, the information distribution server sequentially searches for a link from the departure node to the destination node with reference to the database, and traces the node and link with the smallest cost information of the link as a guide route. The shortest route can be guided to the portable navigation terminal. As such a route search method, a method called label determination method or Dijkstra method is used. Patent Document 1 also discloses a route search method using this Dijkstra method.

  A route search system that searches for routes that use transportation is a database of operation time data of each transportation based on route search conditions such as departure date, departure location, destination, arrival time specified by the user. It has a time database and data that makes the traffic network a database based on this. Then, referring to these databases, each available means of transportation (individual trains and route buses) connecting the departure point and destination, including connections (transfers), is sequentially traced to meet the route search conditions. It is configured to present one or a plurality of candidates for a guide route (departure station, destination station, route, train, etc.). As route search conditions, it is generally possible to specify conditions such as required time, number of transfers, and fares.

  In addition, as a system for conducting searches and guidance related to transportation facilities, a terminal device such as a mobile phone is connected to an information distribution server for guiding route information and timetable information of transportation facilities, and a desired departure station, departure time, destination station, etc. There is also provided a guidance system that can specify information, receive information on routes, trains, trains and other transportation means that can be boarded, and display them on a terminal device. In general, when such use is performed from a terminal device, address information such as a URL (Uniform Resource Locator) or a domain name for specifying a location where information to be downloaded exists is input to the terminal device and specified by the address. The information distribution server (information site) is accessed to download desired information.

  The route search data in the navigation system for route search, route guidance, etc. using the transportation means, as well as the road network data in the in-vehicle navigation system and the pedestrian navigation system, each station on the traffic route as a node, In addition to data obtained by networking stations as two-way links, the operation time and required time of each link are added as link cost data for each means of transportation operated on each traffic route. Furthermore, there is a system in which fare data is added and the fare of the searched guide route is guided together.

  Therefore, the guidance route data distributed to the terminal device includes a route search condition specified by the user, such as a route route from the departure point to the destination, and buses, trains, trains, and times that guide the ride, and the operation. A timetable or a so-called station pasted timetable posted at a station is processed as it is or into a format such as display data that can be displayed on a necessary part, and distributed to the terminal device. The terminal device can check the route and the transportation means to be boarded by displaying the guidance route data, the operation timetable, or the station pasted timetable.

  A route search method for performing a route search using a transportation facility is disclosed as a traffic network route search method in, for example, the following Patent Document 2 (Japanese Patent Laid-Open No. 2000-258184). The traffic network route search method disclosed in Patent Document 2 expresses a traffic network from a starting point to a destination point by using a node as a point and a link between points as a link. It is a traffic network route search method that searches under conditions.

  In this method, as the route from the departure point and destination point to the transportation station to be used, the straight distance from the departure point and destination point to the transportation station to be used, and from the destination point to the transportation station to be used. The average distance is calculated using latitude and longitude information as a variable, the average cost is calculated using the linear distance as a variable, the stations of all the transportation facilities included in the cost range specified by the average cost are determined, and the walking route The total walking network is expressed by incorporating the obtained walking route into the traffic network route of the transportation system, and the search is performed under the cost condition obtained by the label determination method using a computer.

  In such a navigation system, a desired facility (a place of interest: POI) located around a specific point such as a current position or specified by a user, for example, a work place or a transportation station. And has the function of providing detailed information of a desired facility. For example, the following Patent Document 3 (Japanese Patent Laid-Open No. 9-264750) discloses the invention of a navigation device.

  This navigation device performs the following processing. That is, facilities around the search point are selected by genre designation. The shortest straight distance between each selected facility and the route searched in advance is calculated. Only facilities whose calculated shortest straight distance is within 150 m are extracted. The left and right positions of each extracted facility with respect to the route traveling direction are detected. The distance to the destination along the guide route is determined at each facility. Each facility data is rearranged according to the obtained distance to the destination.

  By performing such processing, the navigation device extracts and displays only the stopping facilities along the route while traveling to the destination, so that the stopping facilities that meet the user's wishes can be easily and quickly displayed. You will be able to choose.

  FIG. 12 is a schematic diagram showing the concept of a general POI search as disclosed in Patent Document 3. As shown in FIG. In FIG. 12, S is a point serving as a reference for POI search, for example, the current position of a terminal device such as a navigation device or a specific point designated by the user. A POI (POI of a desired category) that is within a certain distance range around this point is searched. In the search, straight line distances L1, L2, and L3 between corresponding POIs, for example, P1, P2, and P3, and the reference point S are obtained, and it is determined whether they are within a predetermined distance range or the circle range of FIG. To do. In Patent Document 3, the distance of the perpendicular line dropped from the POI to the route is obtained to identify the POI at the shortest distance. In FIG. 12, since each position coordinate is represented by latitude and longitude, the linear distance is calculated using the coordinates of two points. As a result, POI (P3) is excluded from the search result because the distance L3 exceeds a certain distance range.

JP 2001-165681 A (FIGS. 1 and 2) JP 2000-258184 A (FIGS. 4 and 7) JP-A-9-264750 (FIGS. 6 and 12)

  Position information in the navigation system is represented by latitude and longitude. Therefore, in general, when searching for facilities located in a predetermined range (search range) with a certain point as a reference, the position information (latitude / longitude) of the reference point and the position information (latitude / longitude) of the location of the facility are used. It is determined for each facility whether or not the straight line distance between the two points is within the search range. For this reason, the process which calculates a straight line distance from the latitude and longitude of two places is needed.

  The navigation device disclosed in Patent Document 3 also performs such arithmetic processing to search for nearby facilities, and finds the facility with the shortest linear distance from the current position along the direction of the guide route. .

  Depending on the POI category, there may be no POI in the search range (150 m or 10 km). In that case, a message indicating that the POI was not found is displayed, but there is a case where the POI is desired to be found first. On top of that, if you know how far away you are from the POI, you can understand. If the search range is set wide from the beginning, the POI can be found easily. However, if there are too many POIs, the sorting process is too heavy and it is impossible to provide a list of POIs quickly. For example, in an urban area, there are not less than 1000 “Izakaya” and “parking lots” within 4 km, and sorting and displaying is a heavy load on the server in a communication navigation system.

  In general, when a user searches for a desired POI, it is sufficient to obtain 10 to 20 POIs as a result of the search. Therefore, the POI search is efficiently performed regardless of the type of POI category. A method is needed. Further, assuming that about 10 to 20 POI search results are obtained, it is preferable that the user can know what range the search has been made.

  The inventor of the present application has made various studies to solve the above problems, and as a result, determined a rectangular area having a predetermined area centered on the current position of the terminal device or a specific point, and the POI located in the area. If the search is performed, the point of interest of the POI can be determined by comparing the size of the boundary information of the rectangular area and the position information of the POI, and the load of the search process can be reduced. Thus, the present invention has been completed. Is. As a result of the POI search located in the rectangular area, if the number of corresponding POIs is too large, the area of the rectangular area is reduced. If the number of POIs is small, the area of the rectangular area is increased. The present invention has been completed by conceiving that POI information can be provided.

  That is, the present invention aims to solve the above-mentioned problems, and has a POI database storing POI information, and searches for POIs located in a predetermined area including a specific point set by a user. An object of the present invention is to provide a POI search system that can reduce the load of POI search and that can provide an appropriate number of POI information quickly.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is
In a POI search system comprising a POI information database storing POI information and comprising POI search means for searching for a POI located in a predetermined area including a specific point set by a user.
The POI search system refers to the POI information database, POI search means for searching for a POI of a desired category located in a rectangular area having a predetermined area centered on the specific point, and a rectangular area having a predetermined area. A rectangular area determination table in which area determination data for determination is set for each predetermined area, a threshold table in which a threshold for selecting the rectangular area is set according to the number of POIs searched by the POI search means, and sorting Means and display means,
The rectangular area determining means determines whether or not the rectangular area needs to be changed by referring to the threshold value table and the rectangular area determining table based on the number of POIs searched by the POI searching means, and the rectangular area needs to be changed. In this case, the corresponding rectangular area determination data is obtained by referring to the threshold value table and the rectangular area determination table, the area of the rectangular area is changed based on the rectangular area determination data, and the POI search means is changed. The POI in the rectangular area is searched, the search results are sorted by the sorting means, and displayed on the display means.

  The invention according to claim 2 of the present application is the POI search system according to claim 1, wherein the threshold value table and the rectangular area determination table are provided for one or a plurality of POI categories and stored in the POI information database. Further, the threshold value and the rectangular area setting data are set based on the total number of POIs corresponding to one or a plurality of POI categories.

  The invention according to claim 3 of the present application is the POI search system according to claim 1 or claim 2, wherein when the POI search system starts a POI search, the POI search means refers to the POI information database. The total number of the corresponding POIs is acquired, and the rectangular area is determined based on the total number of the POIs.

  The POI search system according to claim 4 of the present application is the POI search system according to claim 1, wherein the POI search system includes operation input means including area selection means for a user to select a rectangular area, When starting the search, the rectangular area determining means determines a rectangular area based on a default or selection by the area selecting means, and the POI searching means searches for a POI in the determined rectangular area. Features.

  According to a fifth aspect of the present invention, in the POI search system according to the fourth aspect, the operation input means includes a threshold value setting means, and the threshold value set by the threshold value setting means is stored in the threshold value table. It is characterized by that.

  The invention according to claim 6 of the present application is the POI search system according to claim 1, wherein the sorting means sorts POIs based on the distance from the specific point to each POI, and the display means is POI information. When displaying, the distance is displayed.

The invention according to claim 7 of the present application is
In a route search server constituting a POI search system comprising a POI information database storing POI information and comprising POI search means for searching for a POI located in a predetermined area including a specific point set by a user.
The route search server refers to the POI information database, and searches for a POI of a desired category located in a rectangular area having a predetermined area centered on the specific point, and a rectangular area having a predetermined area. A rectangular area determination table in which area determination data for determination is set for each predetermined area, a threshold table in which a threshold for selecting the rectangular area is set according to the number of POIs searched by the POI search means, and sorting Means and display means,
The rectangular area determining means determines whether or not the rectangular area needs to be changed by referring to the threshold value table and the rectangular area determining table based on the number of POIs searched by the POI searching means, and the rectangular area needs to be changed. In this case, the corresponding rectangular area determination data is obtained by referring to the threshold value table and the rectangular area determination table, the area of the rectangular area is changed based on the rectangular area determination data, and the POI search means is changed. The POI in the rectangular area is searched, the search results are sorted by the sorting means, and displayed on the display means.

  The invention according to claim 8 of the present application is the route search server according to claim 7, wherein the threshold value table and the rectangular area determination table are provided for one or a plurality of POI categories and stored in the POI information database. Further, the threshold value and the rectangular area setting data are set based on the total number of POIs corresponding to one or a plurality of POI categories.

  The invention according to claim 9 of the present application is the route search server according to claim 7 or claim 8, wherein when the route search server starts a POI search, the POI search means refers to the POI information database. The total number of the corresponding POIs is acquired, and the rectangular area is determined based on the total number of the POIs.

  The invention according to claim 10 of the present application is the route search server according to claim 7, wherein the sorting means sorts the POIs based on the distance from the specific point to each POI, and each POI information includes the It includes the distance from a specific point to each POI.

The invention according to claim 11 of the present application is
In a POI search method in a POI search system comprising a POI information database storing POI information and having POI search means for searching for a POI located in a predetermined area including a specific point set by a user,
The POI search system refers to the POI information database, POI search means for searching for a POI of a desired category located in a rectangular area having a predetermined area centered on the specific point, and a rectangular area having a predetermined area. A rectangular area determination table in which area determination data for determination is set for each predetermined area, a threshold table in which a threshold for selecting the rectangular area is set according to the number of POIs searched by the POI search means, and sorting Means and display means,
A determination step for determining whether the rectangular area needs to be changed by referring to the threshold value table and the rectangular area determination table based on the number of POIs searched by the POI search unit; If the change is necessary, referring to the threshold value table and the rectangular area determination table to obtain the corresponding rectangular area determination data, and changing the area of the rectangular area based on the rectangular area determination data;
The POI search unit includes a step of searching for a POI in the changed rectangular area, a step of sorting search results by the sort unit, and a step of displaying the sorted POI information on the display unit. It is characterized by that.

  The invention according to claim 12 of the present application corresponds to the POI search method according to claim 11, wherein the POI search means refers to the POI information database when the POI search system starts the POI search. The method includes obtaining a total number of POIs and determining the rectangular area based on the total number of POIs.

  The invention according to claim 13 of the present application is the POI search method according to claim 11, wherein the POI search system includes an operation input means including an area selection means for the user to select a rectangular area, When starting the search, the rectangular area determining means determines a rectangular area based on a default or selection by the area selecting means, and the POI searching means searches for a POI in the determined rectangular area. And a step.

  The invention according to claim 14 of the present application is the POI search method according to claim 11, wherein the sorting means sorts the POI based on the distance from the specific point to each POI. Including the processing, the display means displays the distance when displaying the POI information.

  In the invention according to claim 1, the POI search system includes a rectangular area determination table in which area determination data for determining a rectangular area having a predetermined area for probing is set for each predetermined area, and the number of POIs searched by the POI search means. And a rectangular area determining unit that refers to the threshold value table and the rectangular area determining table based on the number of POIs searched by the POI searching unit. If the rectangular area needs to be changed, the corresponding rectangular area determination data is obtained by referring to the threshold value table and the rectangular area determination table, and the rectangular area is determined based on the rectangular area determination data. The area of the area is changed, and the POI search means searches for the POI in the changed rectangular area and the search result is sorted by the sort means. Sorts and displays it on the display means.

  According to such a configuration, a rectangular area having a predetermined area is determined with the current position of the terminal device or a specific point as the center, and the corresponding POI is determined by comparing the size of the boundary information of the rectangular area and the position information of the POI. As a result, the load on the POI search process can be reduced. As a result of the POI search in the rectangular area, if the number of corresponding POIs is too large, the area of the rectangular area is reduced, and if the number of POIs is small, the area of the rectangular area is increased to an appropriate number of POIs. Therefore, it is possible to quickly provide an appropriate number of desired POI information.

  In the invention according to claim 2, in the invention according to claim 1, the threshold value table and the rectangular area determination table are provided for each of one or a plurality of POI categories and stored in the POI information database. The threshold value and the rectangular area setting data are set based on the total number of POIs corresponding to the POI category.

  According to such a configuration, an appropriate rectangular area can be determined according to the total number of POIs accumulated in the POI information database for each category.

  In the invention according to claim 3, in the invention according to claim 1 or claim 2, when the POI search system starts the POI search, the POI search means refers to the POI information database and applies the corresponding POI. The rectangular area is determined based on the total number of POIs.

  According to such a configuration, an appropriate rectangular area corresponding to the total number of POIs stored in the POI information database for each category can be determined and a POI search can be started, so that an efficient search can be performed.

  In the invention according to claim 4, in the invention according to claim 1, the POI search system includes an operation input means including an area selection means for a user to select a rectangular area, and starts a POI search. The rectangular area determining means determines a rectangular area based on default or selection by the area selecting means, and the POI searching means searches for a POI in the determined rectangular area.

  According to such a configuration, a rectangular area having a desired area designated by the user of the terminal device can be determined and the POI search can be started.

  In the invention according to claim 5, in the invention according to claim 4, the operation input means includes a threshold value setting means, and stores the threshold value set by the threshold value setting means in the threshold value table.

  According to such a configuration, the reference for changing the rectangular area can be customized by the user of the terminal device.

  In the invention according to claim 6, in the invention according to claim 1, the sorting means sorts the POI based on the distance from the specific point to each POI, and the display means displays the POI information. The distance is displayed.

  According to such a configuration, the searched POIs can be presented to the user of the terminal device in order of distance, and the distance to each POI is displayed, so that the user can display the displayed POI. It becomes possible to easily determine whether or not to move.

  In the inventions according to claims 7 to 10, it is possible to provide route search servers constituting the POI search system according to claims 1 to 4, respectively. In the inventions according to the twelfth, thirteenth and thirteenth aspects, it is possible to provide a POI search method in the POI search system according to the first, third, fourth and sixth aspects, respectively.

  Hereinafter, specific examples of the present invention will be described in detail with reference to examples and drawings. However, the embodiments described below illustrate a POI search system for embodying the technical idea of the present invention, and are not intended to identify the present invention as this POI search system. It is equally applicable to the POI search system of other embodiments included in the scope of claims.

  FIG. 1 is a diagram showing a system configuration of a POI search system 10 according to an embodiment of the present invention. As shown in FIG. 1, the POI search system 10 includes a terminal device 20 and a route search server 30 that are connected via a network 12. This POI search system 10 includes a POI information distribution server 50 that provides detailed information such as the location of POI (Point of Interest) that belongs to various categories, service contents, advertisements, map data, traffic route data, and operation time. It is configured with various information distribution servers 51 that provide table data, contents such as music and various images, and other information.

  The route search server 30 can acquire necessary data from the POI information distribution server 50 or other information distribution server 51 via the network 12 and add it to its own database. Similarly, a search request can be transmitted to the POI information distribution server 50 or another information distribution server 51 to obtain a desired search result.

  The POI search system 10 according to the present invention is not limited to the above configuration, and the route search server 30 may have a navigation service function and a map distribution server function that distributes a map of the POI location. . Further, instead of the route search server 30, a server having only a POI search function can be used. The terminal device 20 may be a mobile phone, and may be a PDA, music player, portable device such as a portable game machine, or a personal computer (PC).

  The route search server 30 shown in FIG. 1 includes a map database 34 and a route search network database 35. When a route search request is received from the terminal device 20, the route search server 30 searches for a route with reference to the route search network database 35. And it has the general navigation function which transmits the guidance route (recommended route) obtained from the result of route search to the terminal device 20. The route search server 30 also includes a POI information database 36 that stores POI information such as the POI location, telephone number, address, and business hours.

  When there is a POI search request for searching for a desired POI located in the vicinity by designating the current position or a specific point of the terminal device 20, the route search server 30 has a predetermined rectangular area centered on the designated point. And the POI located in the rectangular area is searched. A rectangular area is a rectangular area in a map representation using the Mercator projection, and is an area in which a boundary line of latitude and longitude separated by a certain distance from a specific point is surrounded, and the POI search is a POI located inside the rectangular area. Extract.

  For example, when searching for a POI in a rectangular area with a distance of 5.6 km on one side, if the current position is the center, the latitude and longitude that are ± 2.8 km away from the latitude and longitude of the center coordinates (current position coordinates) It is checked whether or not the target POI is included inside the boundary line. (Since the ground surface is a spherical surface, it is not strictly a rectangular area, but it is processed on the coordinates of a planar map by Mercator projection). Since the distance from the center position to each POI is not calculated, extraction can be performed very quickly.

  That is, since the position information indicating the POI location is composed of latitude and longitude, when the rectangular area is determined, the latitude and longitude information of the boundary line and the latitude and longitude of the position information of each POI By comparison, it is possible to easily determine the POI located in the rectangular area. Accordingly, it is possible to reduce the load of calculation processing in the POI search as compared with the conventional processing for calculating the distance from the designated point to the POI.

  Further, the POI search system 10 according to the present embodiment has a rectangular area when the number of corresponding POIs is too large as a result of POI search located in the rectangular area, and rectangular areas when the number of POIs is small. Is increased so that the number of POIs in the rectangular area becomes an appropriate number. Therefore, as described later, the POI search system corresponds to a rectangular area determination table in which area determination data for determining a rectangular area of a predetermined area is set for each predetermined area, and the number of POIs searched by the POI search means. And a threshold value table in which threshold values for selecting the rectangular area are set.

  Then, in starting the POI search, the POI search system 10 refers to the POI information database 36, acquires the total number of relevant POIs, and determines a rectangular area based on the total number of POIs. The data for determining the rectangular area can be set in a rectangular area determination table and a threshold table.

  When a corresponding POI located in a rectangular area centered on a specific point is searched in such a procedure, the POIs are sorted in the order of the distance from the specific point to each POI, and sorted in the display means. Based on the results, POIs are displayed in order. The displayed POI information includes the name, location, telephone number, business guidance, etc. of each POI, and information on the distance from a specific point may be displayed simultaneously.

  When there is a request for obtaining map data by designating a desired point or POI from the terminal device 20, the route search server 30 reads out the corresponding map data by referring to the map database 34 and distributes it to the terminal device 20. When the terminal device 20 requests a route search from the route search server 30 and receives a route guidance service, the terminal device 20 sets a desired departure place and destination and transmits a route search request to the route search server 30. To do. If there is a stopover point between the departure point and the destination point, the stopover point is also set.

  As a method of setting these points, a route search condition input screen is displayed on the display means, a method of inputting the name, address (location), and telephone number of the point, a map is displayed on the display screen, and a map is displayed. A method of selecting a desired point by selecting the cursor is used. The starting point, waypoint, and destination are generally set to a specific POI location, but the position of a link or node on the road closest to the POI may be used as the POI location for route search. .

  When there is a route search request from the terminal device 20, the route search server 30 searches the route search network database 35 for an optimum route (guide route) from the designated departure point to the destination, and from the map database 34. The guide route data is transmitted to the terminal device 20 together with the read map data.

  When receiving the map data and the guidance route data from the route search server 30, the terminal device 20 displays a map image centered on the current position of the terminal device 20 or a specific point set by the terminal device 20 on the display screen. On the map image, a current position mark indicating the current position of the terminal device 20 and a guide route image indicating the guide route are superimposed and displayed.

  As described above, the POI search system 10 according to the present embodiment can determine the POI in the rectangular area only by comparing the latitude and longitude by searching for the POI by defining a rectangular area having a predetermined area in the POI search. Since it is configured as described above, calculation processing for POI search can be reduced as compared with the conventional method of calculating the distance from a specific point to POI and searching for POI within a certain distance range. Become.

  As a result of the POI search located in the rectangular area, if the number of corresponding POIs is too large, the area of the rectangular area is reduced, and if the number of POIs is small, the area of the rectangular area is changed to an appropriate number. In this way, it is possible to prevent a problem that POIs cannot be searched at all or that too many POIs are searched.

  When starting the POI search, the POI information database 36 is referred to obtain the total number of POIs that meet the POI search condition, determine a rectangular area having a predetermined area according to the total number, and search the POI. As a result, if necessary according to the number of retrieved POIs, the size of the rectangular area is changed to retrieve POIs. As a result, the number of retrieved POIs is an appropriate number, so even if a distance from a specific point to each POI is provided, the processing load for calculating the distance can be kept within a certain range. It becomes like this.

  Hereinafter, the POI search system 10 according to an embodiment of the present invention will be described based on specific examples. Before that, the detailed configuration of the POI search system 10 according to the present invention will be described. FIG. 2 is a block diagram showing a detailed configuration of the POI search system 10 of FIG.

  The terminal device 20 is a terminal capable of receiving a navigation service, and includes a control unit 201, a communication unit 21, a GPS reception unit 22, a processing request unit 23, a distribution data storage unit 24, a display unit 25, an operation input unit 26, and the like. It is prepared for. The operation input unit 26 includes an area setting unit 261 and a threshold setting unit 262.

  When a POI search is requested from the terminal device 20 to the route search server 30, a desired POI category is designated and a point serving as a reference for POI search is set. The point is specified as a reference point, for example, a desired point such as the current position of the terminal device 20 or a transportation station or work place. The POI search searches for a POI located around a set specific point. The POI is stored in the POI information database 36 by category, and the user makes a POI search request by designating a desired category.

  The POIs that interest users are diverse, including movie theaters, theaters, various theme parks, event venues, hotels, restaurants, taverns, gas stations, convenience stores, department stores, shopping malls, and so on. The POI information is accumulated by classification into categories, including the location (latitude / longitude) of each POI. The category is also hierarchized from a large concept to a small concept, and a POI search request is made by designating the category of the POI to be searched from the category list. FIG. 3 is a diagram showing an example of the configuration of POI information stored in the POI information database 36. As shown in FIG. 3, the stored POI information includes a category to which the POI belongs, a POI (name), a POI location (latitude / longitude), a homepage (URL), a business guide, and the like.

  On the other hand, the route search server 30 includes control means 301, communication means 31, distribution data editing means 32, POI search means 33, sort means 331, map database 34, route search network database 35, POI information database 36, rectangular area determination. Means 37, a threshold table 371, a rectangular area determination table 372, a processing request storage means 38, a route search means 39, and the like are provided.

  When there is a route search, POI search, or map distribution request from the terminal device 20, the route search server 30 primarily stores it in the processing request storage unit 38. If the request is a route search request, the route search means 39 searches the route search network database 35 for an optimum route or a recommended route (guide route). The searched guide route data is edited by the distribution data editing means 32 and distributed to the terminal device 20. Further, map data including the guide route is read from the map database 34 and distributed to the terminal device 20.

  In the rectangular area determination table 372, area determination data for determining a rectangular area having a predetermined area is set for each predetermined area. In the threshold table 371, thresholds for selecting a rectangular area are set according to the number of POIs searched by the POI search means 33. FIG. 4 is a diagram illustrating an example of rectangular area determination data set in the rectangular area determination table 372.

  As shown in FIG. 4, in the rectangular area determination table 372, the length (distance) of one side of the rectangular area is attached with the rectangular area ID so that the size of the rectangular area changes by 2 times the area ratio. Is set. In the case of FIG. 4, the rectangular area ID01 has a side length (distance) of the rectangular area of 250 m. Based on this distance, the rectangular area is determined by determining the latitude and longitude of the boundary line of the rectangular area around the specific point (current position or designated point) serving as a reference. Therefore, the rectangular area area of the rectangular area ID02 in which the distance is set to 350 m is almost twice as large as the rectangular area area of the rectangular area ID01. Hereinafter, similarly, the rectangular area determination data is set so that the area of the rectangular area becomes approximately twice as large.

  Therefore, in POI search processing, it is easy to determine whether or not the POI is located inside the rectangular area by simply comparing the latitude and longitude of each POI with the latitude and longitude of the rectangular area boundary line. It is possible to determine whether or not it is located within a predetermined distance range by calculating a straight line distance between two points from the latitude and longitude of the reference point and the latitude and longitude of the location point of each POI as in the past. Compared with this, the processing load can be reduced.

  If the area of the rectangular area is increased, the hit rate when a desired POI located in the rectangular area is searched increases, and if the area of the rectangular area is reduced, the desired POI located in the rectangular area is increased. The hit rate when searching is low. Therefore, an appropriate number of POIs can be obtained as a search result by performing POI search by changing the area of the rectangular area.

  Location density varies depending on the category of POI, and POIs with high location density have a large total number of POIs, and there is a high probability of hitting even if searching within a narrow area, and when searching within a wide area, the number of POIs that hit will increase. This increases the load on the POI search process. Conversely, POIs with low location density have a small total number and may not be hit when searched in a narrow area, and if a search is made within a wide area, the corresponding POI can be searched. Therefore, it is preferable that the rectangular area determination table 372 is appropriately set according to the total number of POIs belonging to the category.

  In starting the POI search, first, the total number of POIs belonging to the specified category is checked with reference to the POI information database 36, and a rectangular area having a size (area) determined by the total number of POIs is determined. Start the search. Then, the POI located in the rectangular area is searched, and if the number is too large, the area of the rectangular area is changed to a small area, and if the number is small, the area of the rectangular area is changed to a large area and again. Search for POI. When the number of POIs becomes an appropriate number, the search is terminated.

  When the distance of each POI, that is, the distance from the reference point to each searched POI is calculated at the stage where the search is completed, the number of POIs is narrowed down to an appropriate number, so that the calculation processing greatly increases. There is no. If the sorting unit 331 sorts the POIs by distance, the POI information can be displayed on the display unit 25 in the order of distance and presented to the user.

  At the start of the search, the POI search may be started by determining a rectangular area with the distance for determining the rectangular area as a default of 4 km (rectangular area ID 09 in FIG. 4). Further, referring to the threshold value table 371, the above-mentioned method of proceeding the POI search while automatically changing the size of the rectangular area until the number of POIs becomes an appropriate number is not adopted. Each time a change in the size of the rectangular area is instructed, the size of the rectangular area may be changed and the POI search may be advanced.

  However, even in this case, if the rectangular area is automatically changed and the POI search is performed on the route search server 30 side and the result is saved, the terminal device 20 has designated the rectangular area change. In addition, the search result can be instantaneously distributed to the terminal device 20.

  For example, when a POI search is started from a rectangular area having a rectangular area ID 10 (distance: 5.6 km), the target POI is included in the latitude and longitude that are ± 2.8 km away from the latitude and longitude of the central coordinates (specific point). (Since the ground surface is a spherical surface, it is not strictly a rectangle, but it is processed on the coordinates of a planar map). Since the distance from the center (specific point) to each POI is not calculated, extraction can be performed very quickly. Further POIs are searched while changing the size (area) of the rectangular area according to the number of POIs searched.

  At this time, when the search is performed efficiently as in the binary search and, for example, 20 POIs are searched as the search results, the larger area in the rectangular area sandwiching the 20 desired search results. If the search result in the rectangular area is adopted, 20 or more POIs can be obtained as the search result.

  For example, 8 rectangular areas with a rectangular area ID 10 (distance: 5.6 km), 12 rectangular areas with a rectangular area ID 12 (distance: 11 km), 32 rectangular areas with a rectangular area ID 13 (distance: 16 km), rectangular When 100 POIs are searched in a rectangular area with area ID 14 (distance: 22 km) (see rectangular area determination table 372 in FIG. 4), a rectangular area (ID 13) with a distance of 16 km and a rectangular area with a distance of 11 km (ID 12) Since 20 POIs are sandwiched, 32 search results in the outer (large area) rectangular area ID 13 (distance 16 km) are adopted as the search results. Even if not strictly performed so far, if a result of 20 to 40 POIs is obtained, the POI search in the rectangular area may be terminated.

  A threshold value table 371 is provided to automatically determine whether or not to change the area of the rectangular area according to the number of POIs obtained by performing POI search for a rectangular area of a certain area. FIG. 5 is a diagram illustrating an example of the threshold table 371. In the threshold value table 371, as shown in FIG. 5, the threshold value of the number of POIs obtained by the POI search unit 33 based on a certain rectangular area is set, and the rectangular area is set according to the threshold range. An area, that is, a rectangular area ID is set, and the rectangular area determining unit 37 determines a rectangular area corresponding to the area, and changes the area.

  For example, in FIG. 5, when the number X of POIs searched for is “X ≧ 100,000”, the rectangular area determining unit 37 sets the area of the rectangular area to the rectangular area ID 04 (distance: 0.7 km). Narrow. The POI search means 33 searches for the POI again based on the rectangular area determined by the rectangular area determination means 37. Similarly, if the number of searched POIs X is “10,000 cases <X <100,000”, the rectangular area determining means 37 changes the area of the rectangular area to the rectangular area ID06.

  It is preferable that the threshold table 371 is set appropriately based on the total number of POIs. If the relationship between the value of the threshold table 371 and the area of the rectangular area is set according to the POI category, the POI search can be performed efficiently. it can.

  FIG. 6 is a schematic diagram illustrating the concept of POI search using a rectangular area in the POI search system 10 according to the present embodiment. The boundary line of the rectangular area is determined by the distance (see FIG. 4) as the rectangular area determination data described above with the specific position S as the center, and the four sides of the rectangular area can be expressed by latitude and longitude. Therefore, when the POIs of P4 to P6 belonging to the category designated as the search condition are in the positional relationship as shown in FIG. 6 with respect to the rectangular area, there is no need to calculate and obtain the distance from a specific point. It is possible to determine whether or not the POI is located in the rectangular area only by comparing the position coordinates (latitude and longitude) of .about.P6 with the latitude and longitude of the boundary line of the rectangular area.

  FIG. 7 is a schematic diagram comparing the general POI search shown in FIG. 12 with the POI search using a rectangular area. If the distances L7 and L8 from the specific point S to the POIs (P7) and (P8) are calculated, the conventional search method is inside a certain distance range (dotted circle in FIG. 7). Extracted as a search result. However, P7 is in a rectangular area (solid rectangular area in FIG. 7) and is extracted as a search result according to the present embodiment, but P8 is not in the rectangular area (solid rectangular area in FIG. 7) and It is not extracted as a search result according to the embodiment.

  Comparing the distance L8 from the point S to the POI (P8) and the distance L7 from the point S to the POI (P7) is “L8 <L7”, and the POI (P8) is closer to the point S than the POI (P7) However, in this embodiment, it is determined that the POI (P8) is not located within the rectangular area, and is not extracted as a search result. Such cases may occur in many cases, but since the user wants to know the POI close to the point S, there is a practical problem even in the case of FIG. 7 occurring near the boundary of the rectangular area. There are few things.

  On the other hand, in the terminal device 20, the control means 201 is a microprocessor having a RAM, a ROM, and a processor (not shown), and controls the operation of each unit by a control program stored in the ROM. The communication means 21 is a communication interface for transmitting and receiving communication data with the route search server 30 and the like via the network 12.

  The GPS receiving means 22 receives a signal from a GPS satellite and calculates the current position by latitude and longitude. The operation input means 26 is composed of keys, dials, etc., and performs input for operating the terminal device 20, and is also used as an input function for route search conditions such as a departure place and a destination. The display means 25 comprises a liquid crystal display panel or the like, and is used for displaying a guidance route or a map distributed (transmitted) from the route search server 30. The display unit 25 also functions as an input unit for operating the terminal device 20 by displaying a menu screen and selecting a desired item from the menu screen using the operation input unit 26.

  When the terminal device 20 requests the route search to the route search server 30, the operation input means 26 is operated, or the menu screen displayed on the display means 25 is operated to obtain a desired departure place, destination, waypoint, etc. Is set, other route search conditions (time condition, number of searched routes, etc.) are set, and a route search is requested. When searching for a desired POI, a POI category selection screen or the like is displayed on the display means 25 and a desired category is designated.

  The operation input means 26 includes an area setting means 261 and a threshold value setting means 262. The setting data of the rectangular area determination table 372 and the threshold value table 371 shown in FIG. 4 are displayed on the display means 25 and desired values are set. be able to. As a result, the user can set the size of the rectangular area and the number of POI searches (threshold value) on a unique basis.

  Distribution data such as map data, POI search results, or guide routes distributed from the route search server 30 to the terminal device 20 is temporarily stored in the distribution data storage unit 24. These data are read out as necessary and displayed on the display means 25. When displaying map data and a guidance route, a map image of a predetermined range is displayed around the current position of the terminal device 20, and the current position mark and the guidance route image are superimposed and displayed.

  FIG. 8 is a diagram illustrating an appearance of the terminal device 20. A terminal device 20 shown in FIG. 8 is a mobile phone as a terminal device, and includes a display unit 25 including a liquid crystal display unit and an operation input unit 26 having a numeric keypad, a dial, a button, and the like. POI information, map data, guide route data, and the like transmitted from the route search server 30 are stored in the distribution data storage unit 24, read out as necessary, and displayed on the display screen 251 of the display unit 25.

  FIG. 9 is a diagram showing an example of the screen transition of the POI search screen displayed on the display screen 251, FIG. 9A is an example of the POI category selection screen, and FIG. 9B is the search result answer screen. It is a figure which shows an example. For example, as shown in FIG. 9A, when a POI corresponding to “Asian / Ethnic” in item number 8 of the gourmet category around the current position is searched, the corresponding POI is searched in a rectangular area with a distance of 2 km. Suppose that it was not done. In this case, as shown in the answer screen of FIG. 9 (b), once the terminal device 20 displays “No match within 2 km”, the user is close to the current position. Can clearly tell that there was no corresponding POI.

  On the route search server 30 side, if the procedure for searching for an appropriate number of POIs while changing the rectangular area described above is performed during this period, the terminal device 20 responds to an inquiry “Would you like to expand the search range?” When “Yes” is selected, the route search server 30 can return the result to the terminal device 20 instantaneously.

  FIG. 10 is a diagram showing an example of a POI information answer screen when an appropriate number of corresponding POIs are searched as a result of the POI search and the search is completed. The POIs are sorted by the sorting unit 331 in the order of distance from the current position, and the POI information corresponding to the designated “gourmet → asia” is displayed in the order of distance.

  In this case, before displaying the POI response screen shown in FIG. 10 or FIG. 9B, the route search server 30 side has already changed the rectangular area to perform the POI search procedure, and the response shown in FIG. 9B. If the answer page of FIG. 10 is also delivered to the terminal device 20 following the page, the result can be obtained instantaneously by simply switching the answer page with the link when “Yes” is selected on the answer screen of FIG. 9B. Can be displayed. Furthermore, by displaying the distance range of the rectangular area from which the search result was obtained (see the display of “It was at 3 to 8 km” in FIG. 10), the user can distribute the desired POI in what range. You can see that As a result, the user can determine whether to give up if walking or to go and see because it is a car.

  FIG. 11 is a flowchart showing a POI search procedure in the POI search system 10 according to the embodiment of the present invention described above. First, the current position or desired point is set as a specific point in the terminal device 20, a desired POI category to be searched is set, and a POI search request is transmitted to the route search server 30.

  First, the route search server 30 receives a POI search request from the terminal device 20 (step S101), and stores this processing request in the processing request storage means 38. The POI search means 33 refers to the POI information database 36 in the process of step S102 and acquires the total number of POIs corresponding to the designated POI category.

  The rectangular area determination unit 37 first determines a rectangular area to be subjected to POI search based on the total number of POIs acquired by the POI search unit 33 (step S103). As described above, the rectangular area is centered on a specific point set in the POI search request, and each side of the rectangle determined by a predetermined distance is determined as the boundary line of the area.

  When the rectangular area is determined, the POI search means 33 searches for the corresponding POI located in the rectangular area (step S104). As described above, the POI located in the rectangular area is determined by comparing the coordinates (latitude and longitude) of each POI with the latitude and longitude of each boundary line of the rectangular area. In step S105, the number of POIs retrieved is detected.

  The rectangular area determination unit 37 refers to the threshold value table 371 and the rectangular area determination table 372 in the determination process of step S106, and determines whether or not the rectangular area needs to be changed based on the number of retrieved POIs. As described above, the rectangular area needs to be changed by narrowing the rectangular area when the number of retrieved POIs is large, and widening the rectangular area when the number of retrieved POIs is small, and performing the POI search again. Based on. The rectangular area to be changed is determined according to the setting contents of the threshold value table 371 and the rectangular area determination table 372.

  If it is determined that the rectangular area needs to be changed in the determination process of step S106, the change is made according to the corresponding rectangular area determination data (the length of the side of the rectangular area) according to the setting contents of the threshold value table 371 and the rectangular area determination table 372. The rectangular area to be determined is determined (step S109), and the process returns to the POI search process in step 104. If it is determined that there is no need to change the rectangular area, it means that the number of retrieved POIs is an appropriate number, and the distance between each retrieved POI and a specific point is calculated. Then, the POI information is sorted in the order of distance by the sorting means 331 (step S107).

  These POI search results are distributed from the route search server 30 to the terminal device 20 and displayed on the display means 25 in the process of step S108 (see FIGS. 9 and 10).

  As described above in detail, according to the POI search system of the present invention, a rectangular area having a predetermined area is determined around the current position of the terminal device or a specific point, and the boundary information of the rectangular area and the position of the POI are determined. Since the corresponding POI is determined by comparing the magnitudes of information, the load on the POI search process can be reduced. As a result of the POI search in the rectangular area, if the number of corresponding POIs is too large, the area of the rectangular area is reduced, and if the number of POIs is small, the area of the rectangular area is increased to an appropriate number of POIs. Therefore, it is possible to quickly provide an appropriate number of desired POI information.

The present invention can be used for POI search in a stand-alone navigation device, but is effective in reducing the search load of a server in a communication type navigation system.
In addition, the user can be instantly provided with information on existing POIs without being limited by distance limitations.

It is a figure which shows the structure of the POI search system concerning the Example of this invention. It is a block diagram which shows the detailed structure of the POI search system concerning the Example of this invention. It is a figure which shows an example of the POI information accumulate | stored in the POI information database. It is a figure which shows an example of the setting data of a rectangular area determination table. It is a figure which shows an example of the setting data of a threshold value table. It is a schematic diagram which shows the concept of POI search using the rectangular area in the POI search system concerning the Example of this invention. It is a schematic diagram which shows contrast with a general POI search and the POI search concerning the Example of this invention using the rectangular area. It is a figure which shows the external appearance of the mobile telephone used as a terminal device. It is a figure which shows an example of the screen transition of the POI search screen displayed on the display screen of a terminal device, FIG.9 (a) is an example of a POI category selection screen, FIG.9 (b) is an example of a response screen of a search result. FIG. It is a figure which shows an example of the POI information reply screen when a suitable number of corresponding POIs are searched as a result of the POI search and the search is completed. It is a flowchart which shows the procedure of POI search in the POI search system concerning the Example of this invention. It is a schematic diagram which shows the concept of the conventional POI search process which searches the desired POI located in a fixed distance range on the basis of a specific point.

Explanation of symbols

10 .... POI search system (navigation system)
12 .... Network 20 ... Terminal device 201 ... Control means 21 ... Communication means 22 ... GPS reception means 23 ... Processing request means 24 ... Distribution data storage Means 25 ... Display means 26 ... Operation input means 261 ... Area setting means 262 ... Threshold setting means 30 ... ... Facility search server (route search server)
301 ... Control means 31 ... Communication means 32 ... Distribution data editing means 33 ... POI search means 331 ... Sort means 34 ... Map database 35 ... Route search Network database 36... POI information database 37... Rectangular area determination means 371... Threshold value table 372 .. rectangular area determination table 38. means

Claims (14)

In a POI search system comprising a POI information database storing POI information and comprising POI search means for searching for a POI located in a predetermined area including a specific point set by a user.
The POI search system refers to the POI information database, POI search means for searching for a POI of a desired category located in a rectangular area having a predetermined area centered on the specific point, and a rectangular area having a predetermined area. A rectangular area determination table in which area determination data for determination is set for each predetermined area, a threshold table in which a threshold for selecting the rectangular area is set according to the number of POIs searched by the POI search means, and sorting Means and display means,
The rectangular area determining means determines whether or not the rectangular area needs to be changed by referring to the threshold value table and the rectangular area determining table based on the number of POIs searched by the POI searching means, and the rectangular area needs to be changed. In this case, the corresponding rectangular area determination data is obtained by referring to the threshold value table and the rectangular area determination table, the area of the rectangular area is changed based on the rectangular area determination data, and the POI search means is changed. A POI search system, wherein a POI in a rectangular area is searched, search results are sorted by the sorting means, and displayed on the display means.   The threshold value table and the rectangular area determination table are provided for each of one or more POI categories, and the threshold value and the rectangular area are based on the total number of POIs corresponding to one or more POI categories stored in the POI information database. The POI search system according to claim 1, wherein setting data is set.   When the POI search system starts a POI search, the POI search means refers to the POI information database, acquires the total number of corresponding POIs, and determines the rectangular area based on the total number of POIs. The POI search system according to claim 1 or 2, characterized in that   The POI search system includes an operation input unit including an area selection unit for a user to select a rectangular area, and when starting the POI search, the rectangular area determination unit selects a default or selection by the area selection unit. 2. The POI search system according to claim 1, wherein a rectangular area is determined based on the POI search means, and the POI search means searches for a POI in the determined rectangular area.   The POI search system according to claim 4, wherein the operation input unit includes a threshold setting unit, and stores the threshold set by the threshold setting unit in the threshold table.   2. The POI according to claim 1, wherein the sorting unit sorts POIs based on distances from the specific point to each POI, and the display unit displays the distances when displaying POI information. Search system. In a route search server constituting a POI search system comprising a POI information database storing POI information and comprising POI search means for searching for a POI located in a predetermined area including a specific point set by a user.
The route search server refers to the POI information database, and searches for a POI of a desired category located in a rectangular area having a predetermined area centered on the specific point, and a rectangular area having a predetermined area. A rectangular area determination table in which area determination data for determination is set for each predetermined area, a threshold table in which a threshold for selecting the rectangular area is set according to the number of POIs searched by the POI search means, and sorting Means and display means,
The rectangular area determining means determines whether or not the rectangular area needs to be changed by referring to the threshold value table and the rectangular area determining table based on the number of POIs searched by the POI searching means, and the rectangular area needs to be changed. In this case, the corresponding rectangular area determination data is obtained by referring to the threshold value table and the rectangular area determination table, the area of the rectangular area is changed based on the rectangular area determination data, and the POI search means is changed. A route search server that searches for a POI in a rectangular area, sorts search results by the sorting means, and displays the results on the display means.   The threshold value table and the rectangular area determination table are provided for each of one or more POI categories, and the threshold value and the rectangular area are based on the total number of POIs corresponding to one or more POI categories stored in the POI information database. The route search server according to claim 7, wherein setting data is set.   When the route search server starts a POI search, the POI search means refers to the POI information database, acquires the total number of corresponding POIs, and determines the rectangular area based on the total number of POIs. The route search server according to claim 7 or 8, wherein the route search server is characterized.   The said sorting means sorts POI based on the distance from the said specific point to each POI, and each POI information includes the distance from the said specific point to each POI. Route search server. In a POI search method in a POI search system comprising a POI information database storing POI information and having POI search means for searching for a POI located in a predetermined area including a specific point set by a user,
The POI search system refers to the POI information database, POI search means for searching for a POI of a desired category located in a rectangular area having a predetermined area centered on the specific point, and a rectangular area having a predetermined area. A rectangular area determination table in which area determination data for determination is set for each predetermined area, a threshold table in which a threshold for selecting the rectangular area is set according to the number of POIs searched by the POI search means, and sorting Means and display means,
A determination step for determining whether the rectangular area needs to be changed by referring to the threshold value table and the rectangular area determination table based on the number of POIs searched by the POI search unit; If the change is necessary, referring to the threshold value table and the rectangular area determination table to obtain the corresponding rectangular area determination data, and changing the area of the rectangular area based on the rectangular area determination data;
The POI search unit includes a step of searching for a POI in the changed rectangular area, a step of sorting search results by the sort unit, and a step of displaying the sorted POI information on the display unit. A POI search method characterized by the above.   When the POI search system starts a POI search, the POI search means refers to the POI information database, acquires the total number of applicable POIs, and determines the rectangular area based on the total number of POIs. The POI search method according to claim 11, further comprising:   The POI search system includes an operation input unit including an area selection unit for a user to select a rectangular area. When starting a POI search, the rectangular area determination unit selects a default or a selection by the area selection unit. 12. The POI search method according to claim 11, further comprising the steps of: determining a rectangular area based on: and the POI search means searching for a POI in the determined rectangular area.   The step of sorting the POI by the sorting means includes a process of sorting the POI based on the distance from the specific point to each POI, and the display means displays the distance when displaying the POI information. The POI search method according to claim 11, wherein

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