JP4603950B2 - Navigation system, POI search method, information distribution server, and portable terminal - Google Patents

Description

The present invention relates to a communication type navigation system including a mobile terminal such as a mobile phone and an information distribution server, and in particular, information on a place of interest (POI) around a position desired by a user is searched and searched. The present invention relates to a navigation system, an information distribution server, and a portable terminal that can guide a route to POI.
In the navigation system as described above, it is possible to select a POI that is close to the desired position in consideration of the distance or time of the actual movement route from the desired position such as the current position to the POI. The present invention relates to a navigation system, an information distribution server, and a mobile terminal that can quickly and efficiently perform a route search to a POI in a distribution server.

  2. Description of the Related Art In recent years, mobile terminals such as mobile phones are equipped with browsers and can access the Internet to receive desired information. In such a system, the user operates a mobile terminal, finds a desired site using a search engine provided in the server, downloads the content of the site, and browses the content with a browser. ing. The content includes information belonging to various categories, and includes information on stores and events, provision of railway timetables, and train transfer guidance.

  In providing information on stores and events, a user operates a mobile terminal to input a store or event category and an area to be searched for a search request. The server searches for stores and events that fall into the specified category and exist in the area, and the information is distributed to the mobile terminal device. In providing the timetable, when the user operates the mobile terminal to designate a route, the timetable of the route is presented on the screen of the display device of the mobile terminal. Further, in the transfer guidance, the recommended route is presented by the user specifying the departure place and the destination.

  Information distribution server is also rich in functions, not just providing timetables and transfer guidance for railway lines and bus lines as described above, but also providing information distribution functions that provide the functions of conventional in-vehicle navigation systems to mobile terminals such as mobile phones A server is also realized. According to such a system, it is possible to provide a navigation service not only for the driver of the automobile but also for the pedestrian.

  A user of a mobile phone can obtain various desired information by using the service as described above. For example, it is possible to obtain information such as a map, business content, price, business hours, and the like regarding a location of interest (Point of Interest: hereinafter simply referred to as POI) in which the user is interested. The POI may be any store or facility such as a hotel, restaurant, department store, theme park, convenience store, gas station, exercise facility, or park. For this reason, POI has an enormous number of types (categories), and there are countless stores and places belonging to the category. The wider the range covered by the information distribution server, the larger the number.

  Therefore, the information distribution server is provided with a POI database in order to provide information regarding these countless POIs to the user. In this POI database, POIs are classified into categories, and this POI category is hierarchized into a large classification, a medium classification, a small classification, and the like because of its large number. The user selects a desired POI category from the menu screen displayed on the mobile terminal and requests data from the information distribution server. In order to select a specific desired POI category, a large classification, a medium classification, The POI category for which information distribution is desired is selected by following the sub-category and category hierarchy.

  When a mobile terminal used by a user is a mobile phone, a recent mobile phone has a GPS receiver and has a positioning function for receiving a signal from a GPS satellite and calculating its current position. The current position can be transmitted to the information distribution server by using it. If the mobile terminal is capable of receiving a navigation service, after obtaining desired specific POI information, a route search to the specific POI is received as a desired starting point such as the current position, home, or work place. You can also.

  Various such POI information providing systems have been proposed. For example, a system disclosed as an “information distribution method” in the following Patent Document 1 (Japanese Patent Laid-Open No. 2003-132483) is known.

  The information distribution method disclosed in Patent Document 1 is a system including an information distribution computer system and a mobile phone as a terminal device. In this information distribution computer system, when guidance information of a certain POI is requested from an external mobile phone, the POI position information and the optimum route information for route search request to the information distribution computer system are added to the guidance information of the desired POI. A link with URL as link information is attached and sent back to the request source. When the link displayed together with the POI guidance information is selected on the mobile phone, the current location detected by the GPS receiver is the departure location, the POI location information is the destination, and the date and time measured by the timing unit is scheduled to depart A route search condition with the date and time is automatically set, and a route search request accompanied by the route search condition information is made to the information distribution computer system.

  That is, this information distribution computer system receives a POI search request from a mobile phone, and searches for a specific POI and distributes the POI guide information (map, business guide, etc.) to the mobile phone. The link information is added and distributed, and when the mobile phone selects the link, the optimum route from the current position to the POI is searched for and distributed.

  Further, a system disclosed as “information providing system and method” in the following Patent Document 2 (Japanese Patent Laid-Open No. 2003-150475) is also known. The information providing system disclosed in Patent Document 2 is a system including a mobile terminal and a Web application server.

  In this information providing system, a user who uses a portable terminal selects a requested service from the displayed provided service menu. Information on the selected service is transmitted to the Web application server. GPS satellites output position information. The mobile terminal receives the position information, calculates the current position based on the received position information, and transmits the current position information to the Web application server via the Internet. The Web application server receives the information on the current position transmitted from the mobile terminal, and transmits information related to the service selected by the user using the mobile terminal and related to the current position to the mobile terminal.

  In general, when there are a plurality of specific POIs belonging to the target POI category around the current position or a desired position (for example, within a radius of 2 km), the POI search system or the route guidance system as described above searches. The position information and related information related to a plurality of POIs are arranged in order from the current position or a desired position and distributed to the mobile terminal. The close order is the order in which the linear distance from the current position or desired position to each POI is short.

  For example, the following Patent Document 3 (Japanese Patent Laid-Open No. 10-281797) discloses an in-vehicle navigation device and a peripheral facility searching method system terminal device that searches for and guides POIs in order of a linear distance from the current position. Yes.

  In the system disclosed in Patent Document 3, categories that are grouped by usage are stored in a table storage unit. When the user inputs a use via the operation unit, the control unit checks the category of the group corresponding to the input use, and searches for a facility existing around the current position of the vehicle from these categories. The searched facilities are arranged in order from the current position, and when the user selects a desired facility, the control unit is configured to search for a guide route from the current position to the selected facility.

  In addition, in a peripheral facility search system such as Patent Document 3, a system configured to efficiently search for a facility (POI) existing within a certain distance range from the current position is disclosed in Patent Document 4 (Japanese Patent Laid-Open No. 2004-2004). A POI information display method and a navigation system disclosed in JP-A-61503 are also known.

  The system disclosed in Patent Document 4 is a navigation system in which cells each having a specific POI are arranged in a cell array, and the cell is based on the distance from the cell position in the cell array corresponding to the cell closest to the user position. Sort into several different levels. This navigation system is configured to extract POIs from cells at a predetermined level, sort POIs according to distances, and display the POIs.

  That is, this system accumulates a cell array in which a specific POI exists in the same manner as a unit map divided by a predetermined latitude and longitude range, and stores the corresponding cell array according to the distance level from the current position. Search efficiency is improved by selecting and searching for a POI existing in the cell.

Japanese Patent Laying-Open No. 2003-132483 (FIG. 1, paragraph [0006]) JP 2003-150475 A (FIG. 1, FIG. 2, paragraph [0013]) JP-A-10-281797 (FIG. 1, paragraphs [0028] and [0029]) Japanese Unexamined Patent Application Publication No. 2004-61503 (FIGS. 4, 6, 7, and 8)

  The system that searches for POIs within a certain range from the current position or desired position and arranges the POIs in the closest order sorts the POIs based on the linear distance as disclosed in Patent Documents 1 to 4 above. It was something to do. However, when the user wants to visit the actually searched POI, it is desirable that a close POI can be selected in consideration of the actual movement route. This is because even if the straight distance is short, it is actually blocked by rivers and railways, and the road may be far.

  However, in the systems disclosed in Patent Documents 1 to 4, the POIs are sorted and guided in order from the current position or the desired position based on the linear distance, and the route search is performed for the POI selected by the user. Since the route is guided, there is a problem that the actual route becomes a detour and there is no guarantee that the nearest POI can be reached.

  In order to solve such a problem, if an actual travel route is searched from the current position or desired position and an attempt is made to guide the POI in the order of the closest route, the information distribution server searches for all the POIs that should be candidates. Need to do. Such a guidance method is not impossible, but requires a considerable amount of time for route search. (1) When a route search for all candidate POIs is performed by the information distribution server, a large number of clients are required from one client (mobile terminal). For example, there is a POI search request for 100 POIs, and if a route search to all POIs is performed, there is a problem that the entire system may be overloaded, such as a time zone in which the search requests are concentrated. It was. Also, (2) in car navigation, since the speed of movement is high, when searching for a large number of POI routes as described above, the current location changes before the route search is completed, and when the search results are distributed, the user is already However, there is a problem that the information becomes useless because it travels a considerable distance.

  The inventor of the present application has conducted various studies to solve the above-described problems. As a result, when there is a POI search request close to the current position or the desired position, first, the time desired by the user from the current position or the desired position or Search the range (service area) on the road network that can be reached by distance, extract the POI within the service area, associate it with the nearest node or link, and make the route from the current position or desired position in order of short distance (or time) It was conceived that the above problems could be solved if the relevant POIs were sorted and guided, and the present invention was completed.

  That is, the present invention has an object to solve the above-mentioned problems, and a POI existing near the desired position can be selected in consideration of an actual movement route from the desired position such as the current position to the POI. An object of the present invention is to provide a navigation system, an information distribution server, and a portable terminal that can efficiently perform a route search to the POI of the information distribution server.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is
A POI database storing POI information including POI position information for each POI;
A search network database storing search network data composed of nodes and links;
Search condition setting means for setting a POI search condition including a reference position and a cost value for designating a range of a service area from the reference position;
A service area search means for performing a service area search for tracing all nodes and links included in a service area that can be reached at the cost value or less by sequentially tracing the nodes from the reference position using the search network data;
Potential value holding means for holding a potential value that is a cumulative link cost for each node searched by the service area search means even after the service area search ;
POI extraction means for extracting a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
Corresponding means for associating one of the nodes or links searched by the service area searching means for each extracted POI with the POI closest to the extracted POI;
POI cost for generating a route distance or required time from the reference position to the POI with reference to the potential value held by the potential value holding unit based on the node or link associated by the association unit Information generating means;
It is a navigation system characterized by comprising.

The invention according to claim 2 of the present application is the navigation system according to claim 1,
Sorting means for sorting the POIs based on potential values of nodes associated with each POI;
Output means for outputting POI information of the POI extracted by the POI extraction means based on the sort result;
Further comprising wherein the Rukoto a.

The invention according to claim 3 of the present application is the navigation system according to claim 1 or 2,
The POI extracting means, among searched node as the service area search result, based on the node corresponding to the range of the service area generates a polygon, characterized that you extract POI in the range of the polygon And

The invention according to claim 4 of the present application is the navigation system according to any one of claims 1 to 3,
The POI database stores the POI information in mesh units of a predetermined geographical area,
A mesh specifying means for specifying a mesh corresponding to the node searched by the service area search means;
The POI extracting means further added to said Rukoto that it contains the location information of the POI in the range of meshes specified by the mesh specifying unit as the extraction conditions POI.

The invention according to claim 5 of the present application is the navigation system according to any one of claims 1 to 4 ,
The POI database holds the POI information for each category,
The search condition setting means includes a desired category in the POI search condition,
The POI extracting means further adds, as a POI extraction condition, that it matches a category included in the POI search condition .

The invention according to claim 6 of the present application is the navigation system according to claim 1 ,
Sorting means for sorting the POIs based on potential values of nodes connected to links associated with each POI;
Output means for outputting POI information of the POI extracted by the POI extraction means based on the sort result;
Further comprising wherein the Rukoto a.

The invention according to claim 7 of the present application is the navigation system according to claim 6,
The POI database stores the POI information in mesh units of a predetermined geographical area,
A mesh specifying means for specifying a mesh corresponding to the link searched by the service area search means;
The POI extracting means further added to said Rukoto that it contains the location information of the POI in the range of meshes specified by the mesh specifying unit as the extraction conditions POI.

The invention according to claim 8 of the present application is the navigation system according to claim 6 or 7,
The POI database holds the POI information for each category,
The search condition setting means includes a desired category in the POI search condition,
The POI extracting means further added to said Rukoto to conform to categories in the POI search condition as an extraction condition for POI.

The invention according to claim 9 of the present application is
A POI database storing POI information including POI position information for each POI;
A search network database storing search network data composed of nodes and links;
Search condition setting means for setting a POI search condition including a reference position and a cost value for designating a range of a service area from the reference position;
A service area search means for performing a service area search for tracing all nodes and links included in a service area that can be reached at the cost value or less by sequentially tracing the nodes from the reference position using the search network data;
Potential value holding means for holding a potential value that is a cumulative link cost for each node searched by the service area search means even after the service area search ;
POI extraction means for extracting a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
Corresponding means for associating one of the nodes or links searched by the service area searching means for each extracted POI with the POI closest to the extracted POI;
POI cost for generating a route distance or required time from the reference position to the POI with reference to the potential value held by the potential value holding unit based on the node or link associated by the association unit Information generating means;
A POI search method in a navigation system comprising:
A first step of searching for all nodes and links included in a service area that the service area search means sequentially traces the nodes from the reference position using the search network data and can be reached below the cost value;
A second step in which the POI extraction means extracts a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
A third step in which, for each POI extracted by the association means, one of the nodes or links closest to the extracted POI among the nodes or links searched by the service area search means is associated with the POI;
The POI cost information generation unit refers to the potential value held by the potential value holding unit based on the node or link associated by the association unit, and the path distance from the reference position to the POI Or a fourth step of generating the required time;
It is characterized by comprising.

The invention according to claim 10 of the present application is the POI search method according to claim 9,
The navigation system sorts the POI based on the potential value of the node associated with each POI, and outputs the POI information of the POI extracted by the POI extraction means based on the sorting result. And further comprising
In the fourth step, the sorting means sorts the POI based on the potential value of the node associated with each POI, and the output means extracts the POI POI extracted by the POI extracting means. It includes a process of outputting information based on the sorting result .

The invention according to claim 11 of the present application is the POI search method according to claim 9 or 10,
The second step includes a process of generating a polygon based on a node corresponding to the range of the service area among the nodes searched as the service area search result, and extracting a POI within the range of the polygon. It is characterized by that.

The invention according to claim 12 of the present application is the POI search method according to any one of claims 9 to 11 ,
The POI database stores the POI information in mesh units of a predetermined geographical area,
The navigation system further comprises mesh specifying means for specifying a mesh corresponding to the node searched by the service area searching means,
Said second step further added to said Rukoto that it contains the location information of the POI in the range of meshes specified by the mesh specifying unit as the extraction conditions POI.

The invention according to claim 13 of the present application is the POI search method according to any one of claims 9 to 12,
The POI database holds the POI information for each category,
The search condition setting means includes a desired category in the POI search condition,
The POI extracting means further added to said Rukoto to conform to categories in the POI search condition as an extraction condition for POI.

The invention according to claim 14 of the present application is the POI search method according to claim 9 ,
The navigation system sorts the POI based on a potential value of a node connected to a link associated with each POI, and the POI information of the POI extracted by the POI extraction unit based on the sorting result. And the output means for outputting, the fourth step, wherein the sorting means sorts the POI based on a potential value of a node connected to a link associated with each POI; The output means includes a process of outputting POI information of the POI extracted by the POI extraction means based on the sorting result .

The invention according to claim 15 of the present application is
An information distribution server connected via a network to a portable terminal that transmits a POI search condition including a reference position and a cost value for designating a range of a service area from the reference position, the information distribution server Is
A POI database storing POI information including POI position information for each POI;
A search network database storing search network data composed of nodes and links;
A service area search means for performing a service area search for tracing all nodes and links included in a service area that can be reached at the cost value or less by sequentially tracing the nodes from the reference position using the search network data;
Potential value holding means for holding a potential value that is a cumulative link cost for each node searched by the service area search means even after the service area search ;
POI extraction means for extracting a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
Corresponding means for associating one of the nodes or links searched by the service area searching means for each extracted POI with the POI closest to the extracted POI;
POI cost for generating a route distance or required time from the reference position to the POI with reference to the potential value held by the potential value holding unit based on the node or link associated by the association unit Information generating means;
It is characterized by providing.

The invention according to claim 16 of the present application is the information distribution server according to claim 15,
Sorting means for sorting the POIs based on potential values of nodes associated with each POI;
Output means for outputting POI information of the POI extracted by the POI extraction means based on the sort result;
Further comprising wherein the Rukoto a.

The invention according to claim 17 of the present application is the information delivery server according to claim 15 or 16,
The POI extracting means, among searched node as the service area search result, based on the node corresponding to the range of the service area generates a polygon, characterized that you extract POI in the range of the polygon And

An invention according to claim 18 of the present application is the information distribution server according to any one of claims 15 to 17 ,
The POI database stores the POI information in mesh units of a predetermined geographical area,
A mesh specifying means for specifying a mesh corresponding to the node searched by the service area search means;
The POI extracting means further added to said Rukoto that it contains the location information of the POI in the range of meshes specified by the mesh specifying unit as the extraction conditions POI.

An invention according to claim 19 of the present application is the information delivery server according to any one of claims 15 to 18 ,
The POI database holds the POI information for each category,
The search condition setting means includes a desired category in the POI search condition,
The POI extracting means further adds, as a POI extraction condition, that it matches a category included in the POI search condition .

The invention according to claim 20 of the present application is the information delivery server according to claim 15 ,
Sorting means for sorting the POIs based on potential values of nodes connected to links associated with each POI;
Output means for outputting POI information of the POI extracted by the POI extraction means based on the sort result;
Further comprising wherein the Rukoto a.

The invention according to claim 21 of the present application is the information distribution server according to claim 20,
The POI database stores the POI information in mesh units of a predetermined geographical area,
A mesh specifying means for specifying a mesh corresponding to the link searched by the service area search means;
The POI extracting means further added to said Rukoto that it contains the location information of the POI in the range of meshes specified by the mesh specifying unit as the extraction conditions POI.

The invention according to claim 22 of the present application is
A POI database storing POI information including POI position information for each POI;
A search network database storing search network data composed of nodes and links;
Based on a POI search condition including a reference position and a cost value for designating a range of service area from the reference position, the cost value is obtained by sequentially tracing nodes from the reference position using the search network data. A service area search means for performing a service area search for searching all nodes and links included in the service area that can be reached below;
Potential value holding means for holding a potential value that is a cumulative link cost for each node searched by the service area search means even after the service area search ;
POI extraction means for extracting a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
Corresponding means for associating one of the nodes or links searched by the service area searching means for each extracted POI with the POI closest to the extracted POI;
POI cost for generating a route distance or required time from the reference position to the POI with reference to the potential value held by the potential value holding unit based on the node or link associated by the association unit Information generating means;
A portable terminal connected to an information distribution server comprising a network,
Search condition setting means is provided for setting POI search conditions including the reference position and a cost value for designating a range of the service area from the reference position.

In the invention according to claim 1,
A POI database storing POI information including POI position information for each POI;
A search network database storing search network data composed of nodes and links;
Search condition setting means for setting a POI search condition including a reference position and a cost value for designating a range of a service area from the reference position;
A service area search means for performing a service area search for tracing all nodes and links included in a service area that can be reached at the cost value or less by sequentially tracing the nodes from the reference position using the search network data;
Potential value holding means for holding a potential value that is a cumulative link cost for each node searched by the service area search means even after the service area search ;
POI extraction means for extracting a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
Corresponding means for associating one of the nodes or links searched by the service area searching means for each extracted POI with the POI closest to the extracted POI;
POI cost for generating a route distance or required time from the reference position to the POI with reference to the potential value held by the potential value holding unit based on the node or link associated by the association unit Information generating means;
Is provided.
Therefore, the service area can first be determined by the service area search, and this service area search can be completed efficiently in a short time. Since this service area search has already searched for the nearest node of each POI, the cost to the link, that is, the route distance to the vicinity of the POI or the required time, the POI in the service area is extracted, and the extracted POI for each POI is extracted. It becomes possible to generate a route distance or a required time as an actual route from the reference position. Thus, a close POI can be selected in consideration of the actual movement route, and even when the straight distance is short, a POI search that excludes a POI that is actually blocked by a river or a railway and has a long road becomes possible.

In the invention according to claim 2, in the navigation system according to claim 1, the POI is sorted based on the potential value of the node associated with each POI, and POI information of the POI extracted by the POI extraction means is obtained. Output based on the sort result.
Therefore, since the route distance or required time to the nearest POI has already been searched by the service area search , the POI in the service area is then extracted, and the route that becomes the actual route from the reference position for each extracted POI It becomes possible to generate a distance or a required time .

In the invention according to claim 3, in the navigation system according to claim 1 or 2, the POI extraction means is based on a node corresponding to the range of the service area among the nodes searched as the service area search result. A polygon is generated, and a POI within the range of the polygon is extracted.
Therefore, a desired POI in the service area can be easily extracted based on the result of the service area search, and the route distance or required time to the extracted POI can be easily generated.

According to a fourth aspect of the present invention, in the navigation system according to any one of the first to third aspects, the POI database stores the POI information in mesh units of a predetermined geographical area, and the service area search means Further comprising mesh specifying means for specifying a mesh corresponding to the searched node, wherein the POI extracting means indicates that the POI position information is included in the mesh range specified by the mesh specifying means. In addition Ru added as extraction conditions.
Therefore, a desired POI in the service area can be extracted based on the result of the service area search, and the route distance or required time to the extracted POI can be easily generated.

According to a fifth aspect of the present invention, in the navigation system according to any of the first to fourth aspects, the POI database holds the POI information for each category, and the search condition setting means includes the POI search unit. A desired category is included in the condition, and the POI extraction means further adds that the category matches the category included in the POI search condition as a POI extraction condition.
Therefore, a desired POI in the service area can be extracted based on the result of the service area search, and the route distance or required time to the extracted POI can be easily generated.

In the invention concerning Claim 6, in the navigation system concerning Claim 1 ,
Sort means for sorting the POI based on the potential value of the node connected to the link associated with each POI, and output means for outputting the POI information of the POI extracted by the POI extraction means based on the sort result And further comprising.
Thus, the nearest node of each POI by service area search, since the cost or path distance or time required to near POI up link is the searched, then extracted the arrival distance of POI, for each POI extracted It is possible to generate a route distance or a required time as an actual route from the reference position .

In the invention according to claim 7, in the navigation system according to claim 6,
The POI database further includes mesh specifying means for storing the POI information in units of meshes of a predetermined geographical area and specifying a mesh corresponding to the link searched by the service area searching means, and the POI extracting means comprises: further Ru added that it contains the location information of the POI in the range of meshes specified by the mesh specifying unit as the extraction conditions POI.
In the invention according to claim 8, in the navigation system according to claim 6 or 7, the POI database holds the POI information for each category, and the search condition setting means includes the POI search condition. The POI extraction means further adds a POI extraction condition that matches the category included in the POI search condition.
Therefore, a desired POI in the service area can be extracted based on the result of the service area search, and the route distance or required time to the extracted POI can be easily generated .

In the inventions according to claims 9 to 14, it is possible to provide a POI search method in the navigation system according to claims 1 to 6 , respectively. In the inventions according to claims 15 to 21, it is possible to provide information distribution servers constituting the navigation system according to claims 1 to 7, respectively. Furthermore, the invention according to claim 22 can provide a portable terminal constituting the navigation system according to claim 1.

  Hereinafter, specific examples of the present invention will be described in detail with reference to examples and drawings. In the following embodiments, a mobile phone is used as a terminal device, and a navigation system that has a POI information providing function in a navigation system that performs route search and route guidance will be described as a specific example. Without being limited to an example, the terminal device may be a mobile terminal such as a vehicle-mounted terminal device. In this specification, a mobile terminal including a mobile terminal is generically named. However, the information distribution server needs to have network search route data and a function for performing route search.

  FIG. 1 is a diagram showing a configuration of a navigation system according to an embodiment of the present invention. As shown in FIG. 1, the navigation system 10 includes a mobile terminal 20 and an information distribution server 30 connected via a network 11 such as the Internet. In order to provide POI information to the terminal device 20, the information distribution server 30 is divided into POI categories, and each POI belonging to the category, its position information (latitude / longitude), and a unit similar to the unit map where the POI is located. POIDB 37, which is a database storing information related to POI such as segment identification numbers (mesh numbers) and business guidance, route search means 33, service area POI range determination means 36, search network data 35, service area A POI determining unit 38, a POI sorting unit 39, and the like are provided.

  All the POI information stored in the POIDB 37 is based on a mesh obtained by dividing an area by a predetermined latitude / longitude, and information on each POI is stored in the corresponding mesh based on the location where each POI exists. One mesh may be the same size as the unit map obtained by dividing the map by latitude and longitude. Of course it can be of different sizes.

  FIG. 2 is a diagram showing the structure of the POI information stored in the POIDB 37 described above. As shown in FIG. 2, the accumulated POI information is divided in units of meshes separated by a predetermined latitude and longitude such as mesh numbers 0001 to 0002, and the POI information existing in the meshes corresponds. Accumulated in the mesh. The accumulated 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. The search network data 35 stores road network data for route search and traffic network data. Road network data is used for route search for automobiles and pedestrians, and traffic network data is used for route search for sections using transportation.

  The information distribution server 30 also includes a control unit 31, a distribution data editing unit 32, and a communication unit 34. Although not shown, the control unit 31 is a microprocessor having a RAM, a ROM, and a processor, and controls the operation of each unit by a control program stored in the ROM. The communication means 34 is an interface for communicating with the portable terminal 20 and the POI information providing server 50 that provides various POI information via the networks 11 and 12. The distribution data editing means 32 is for editing the results of route search and POI search into data for distribution to the mobile terminal 20. The information distribution server 30 can collect POI information from various POI information providing servers 50 via the network 12 and register it in the POIDB 37 to enhance the POI information that can be provided to the user.

  The mobile terminal 20 is a mobile phone equipped with positioning means such as a GPS receiver, for example, and can perform a peripheral search around the current location and the destination, that is, a desired POI search. When a peripheral search request is sent to the information distribution server 30 with the current position and destination position information, the information distribution server 30 considers the current position of the mobile terminal 20 or the position of the destination and the route to the POI, It is configured so that a POI search request in which the required time of the route or the distance of the route is within a desired range can be made. Hereinafter, the distance or time of this route is referred to as a service area. In the POI search, the portable terminal 20 displays a POI category selection screen, and the user selects a desired POI category, inputs a desired service area (distance or time), and transmits a POI search request to the information distribution server 30. Then, a POI belonging to the POI category is searched. In the following description, a specific example will be described taking a peripheral search based on the current position as an example.

  The service area search is to determine an area that can be reached from a certain point (for example, the current location) at a predetermined cost or less (distance (route distance), required time, etc.) without setting a destination. This technology is mainly used for store opening plans and real estate selection. This technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-187653 filed and published by the present applicant. This technique discloses a method for searching a service area of a train line.

  In the present embodiment, a service area search is performed from the current location under predetermined conditions (route distance, required time), and as a result, the service area is obtained graphically, and the POI included in the graphic is used as a list candidate. After the service area search is executed, the potential (shortest cost) of each node has been calculated from a certain point by the Dijkstra method, so the potential of the node adjacent to the POI (nearest node) is the cost of the route to that POI. Thus, the POIs can be sorted and guided in ascending order of cost, that is, in the order of the actual route length from the current position to the POI or the time decreasing. In the following embodiments, a route distance including a time required for a route is simply referred to as a route distance.

  When the information distribution server 30 receives a search request specifying the current position, the desired service area, and the POI category from the mobile terminal 20, the route search means 33 uses the search network data 35 to specify the service area. Search for all reachable nodes (nodes on the road network) in the range. This search is called a service area search, and generally uses the Dijkstra method, which is used for route search, and follows the nodes sequentially from the current position (called diffusion in the Dijkstra method), and its potential (cumulative distance or time to the passed node) ) Stops reaching the designated service area (predetermined distance or time). All nodes when the diffusion is stopped are nodes that can be reached at a predetermined distance or time from the current position. Hereinafter, this node is referred to as a reachable node.

  Next, the service area POI range determination means 36 creates a polygonal figure (polygon) connecting the reachable nodes searched by the route search means 33 by the service area search, and determines the POI range that overlaps the service area. The service area POI discriminating means 38 extracts a POI that is within the service area POI range and is present within the polygon range, and associates the closest node with each POI. This detailed method will be described later in detail. That is, this process associates the POI with the route node, and the route to the POI has already been searched. In addition, since the service area search is performed, if the search itself is within a realistic distance or time range, the search is completed in a very short time, and at the same time, the route search to the POI in the service area is completed. It is possible to provide guidance in consideration of the route to the POI efficiently.

  The road network for route search is configured as follows. For example, when the road is composed of roads A, B, and C as shown in FIG. 3, the end points, intersections, and bending points of the roads A, B, and C are used as nodes, and the roads connecting the nodes are directed links. Link cost data and configuration, which is expressed as node data (node latitude / longitude), link data (link number), and link cost of each link (link distance or time required to travel the link) Is done.

  That is, in FIG. 3, ◯ and ◎ indicate nodes, and ◎ indicates a road intersection. Directional links connecting the nodes are indicated by arrow lines (solid line, dotted line, two-dot chain line). As for the links, there are links facing in the upward and downward directions of the road, but in FIG. 3, only the links in the direction of the arrows are shown for the sake of simplicity.

  When route search is performed using such road network data as a route search database, links linked from the starting node to the destination node are traced to accumulate the link cost, thereby minimizing the accumulated link cost. Search and guide the route. That is, in FIG. 3, when a route search is performed with the departure point as the node AX and the destination as the node CY, the road travels from the node AX to the road A, turns right at the second intersection, enters the road C, and reaches the node CY. The link cost is accumulated sequentially, and a route that minimizes the accumulated link cost is searched for and guided.

  Although other routes from the node AX to the node CY are not shown in FIG. 3, in reality there are other such routes, so a possible route from the node AX to the node CY is similarly searched. Of these routes, the route with the lowest link cost is determined as the optimum route. This method is performed by, for example, a known method called the Dijkstra method.

  On the other hand, the traffic network data for route search of the transportation system is configured as follows. For example, as shown in FIG. 4, in the case of traffic routes A, B, and C, each station (each airport on an aircraft route) provided on each traffic route A, B, and C is used as a node, and the nodes are connected. A section is represented by a directional link, and node data (latitude / longitude) and link data (link number) are network data. In FIG. 4, ◯ and ◎ indicate nodes, ◎ indicates a transit point (such as a transfer station) on a traffic route, and a directional link connecting each node is indicated by an arrow line (solid line, dotted line, two points). This is indicated by a chain line). As for the links, there are links facing in the upward and downward directions of the traffic route, but in FIG. 4, only the links in the direction of the arrows are shown for the sake of simplicity.

  However, the traffic network basically has a different link cost compared to the road network. In other words, in the road network, the link cost is fixed and static. However, in the traffic network, as shown in FIG. 4, trains and airplanes (hereinafter referred to as individual trains and airplanes) that operate traffic routes are used. A plurality of means of transportation). The time of departure from one node and the time of arrival at the next node are determined for each means of transportation (specified by timetable data and operation data), and individual routes do not necessarily link to adjacent nodes. There is a case. This is the case, for example, with express trains and trains that stop at each station. In such a case, a plurality of different links exist on the same traffic route, and the required time between nodes may differ depending on the transportation means.

  In the transportation network illustrated in FIG. 4, a plurality of transportation means (routes) Aa to Ac... Exist on the same link of the transportation route A, and a plurality of transportation means (routes) Ca to Cc. Will do. Therefore, unlike a simple road network, the transportation network of a transportation facility has a data amount proportional to the total number of transportation means (routes such as individual aircraft and trains). For this reason, the data of the traffic network becomes a huge amount of data compared to the data amount of the road network. Accordingly, much time is required for route search accordingly.

In order to search for a route from a certain departure point to a certain destination using such traffic network data, all the means of transportation that can be used (ride) when arriving from the departure point to the destination are searched. It is necessary to specify the means of transportation that matches the search conditions.
For example, in FIG. 4, when a specific departure time is designated with the departure point as the node AX of the traffic route A and the route search is performed with the node CY of the traffic route C as the destination, the route operates on the traffic route A. Of the transportation means Aa to Ac..., All transportation means after the departure time are sequentially selected as the departure route. And, based on the arrival time at the transit node on the transit route C, among all the transit means Ca-Cc... The total time required for each route, the number of transfers, and the like are guided.

  On the other hand, as shown in FIG. 1, the mobile terminal 20 is distributed from a control unit 21, a communication unit 22, a positioning unit 23 including a GPS receiver, a display unit 24 including a liquid crystal display unit, and an information distribution server 30. Distribution data storage means 25 for storing data, distribution request editing means 26 for editing various requests to the information distribution server 30, and operation / input means 27.

  The control means 21 includes a microprocessor (CPU) having a RAM and a ROM (not shown), and controls the operation of each unit by a control program stored in the ROM. The operation / input means 27 is for operation / input means composed of numeric keys, alphabet keys, other function keys, selection keys, scroll keys, and the like. From the menu screen displayed on the display means 24 which is output means. Various input operations are performed by selecting a desired menu or operating keys. Accordingly, the display unit 24 also functions as a part of the operation / input unit 27. The communication unit 22 is an interface for communicating with the information distribution server 30 via the network 11.

  When the user wants to request the information distribution server 30 to search for POI, the user operates the operation / input means 27 on the portable terminal 20 to display the service menu screen shown in FIG. Do. For example, when the user wants to search for a pharmacy close to the current location, the POI category “pharmacy” is selected on the peripheral search menu screen, and the range of the service area is input, for example, 10 minutes on foot (or a route distance of 800 m). . The POI category (pharmacy) selected as described above and the input condition (service area) are edited by the distribution request editing unit 26 as a POI search request and transmitted to the information distribution server 30.

  When the information distribution server 30 receives the POI search request, the route search means 33 performs a service area search with reference to the search network data 35. FIG. 6 is a schematic diagram for explaining the concept of a service area search. In FIG. 6, P is a current position measured by the mobile terminal 20, a black circle represents a node, and a solid line connecting the black circles represents a link. In the service area search by the Dijkstra method, links and nodes are traced in all directions of the links L1 to L4 from the current position P, and the accumulated link cost (distance or time of the traced link) is calculated for each node. Of potential. When the potential of the node reaches a predetermined distance or time range, the diffusion (search) to the link and node ahead is stopped. In FIG. 6, the nodes N1 to N9 and the like are the nodes with the highest potential in the service area, and this node is the farthest node that can be reached within a predetermined service area. The calculation process and calculation result of the Dijkstra method are temporarily stored and used later for POI sorting and route guidance.

  Next, the service area POI range determination means 36 creates a polygonal figure (polygon) that connects the nodes in the service area including the reachable nodes N1 to N9 searched by the route search means 33. Hereinafter, this polygon is referred to as a service area polygon. FIG. 7 is a schematic diagram showing the concept of processing for drawing the reachable node shown in FIG. That is, in FIG. 7, P represents the current position measured by the mobile terminal 20, the black circle represents a node, and the solid line connecting the black circles represents a link. The nodes N1 to N9 and the like are the farthest nodes from the current position P among the reachable nodes. As shown by a dotted line in FIG. 7, the node is looked at every predetermined angle (10 °) around the current position P, and is the farthest node for each angle region (in FIG. 7, nodes N1 to N9, N10 to N21). And the node number is stored. If there is no node in the angle area, the node is not stored. For each angle range, a farthest node (farthest from the current position) is connected to form a service area polygon.

  The inside of the polygon can be expressed by, for example, a process of painting on the video RAM. If the video RAM is filled, it can be seen that the position corresponding to the bit is inside the polygon, that is, within the reachable area. (There is no need to actually perform it on the video RAM. Since it is not necessary to show it, it can be processed even if it is developed on a general RAM used for other processing). The service area can now be represented graphically.

  Thereafter, the service area POI determination means 38 extracts the corresponding POI (here, a pharmacy) existing in the service area polygon created by the service area POI range determination means 36. As described in the configuration of the POIDB 37 (see FIG. 2), information on each POI is stored in the corresponding mesh based on the location where each POI exists, with a mesh obtained by dividing an area by a predetermined latitude and longitude. Accumulated. Therefore, the service area POI range determination means 36 can specify the mesh where the service area polygons overlap, and can thereby determine the service area POI range.

  That is, the service area POI determination means 38 extracts POIs that match the search conditions from all the POIs present in the meshes M1 to M4 in which the service area polygons 81 are geographically overlapped as shown in FIG. That is, FIG. 8 is a schematic diagram showing the relationship between the service area polygon 81 formed as shown in FIG. 7 and the mesh unit in which the POI information is accumulated, and meshes M1 to M4 overlapping the service area polygon 81 are shown. Show.

  The service area POI discriminating means 38 narrows down the corresponding POI from all the POIs existing in the meshes M1 to M4 overlapped with the service area polygon 81 on the condition of the category “pharmacy” designated as the search condition (see FIG. 2). ). Then, the narrowed “pharmacy” within the service area polygon 81 is extracted. In FIG. 8, POI 3 is “pharmacy”, but it is not within the meshes M1 to M4 overlapping the service area polygon 81, so it is not targeted for narrowing down.

  Since POI1 and POI2 are in meshes M1 to M4 that overlap with the service area polygon 81, they are targeted for narrowing down. Since POI1 is inside the service area polygon 81, it is extracted as the corresponding POI. On the other hand, since POI2 is outside the service area polygon 81, it is not extracted as the corresponding POI. Since the service area polygon 81 means a range that is not reachable at a distance or time on a route desired by the user, POI1 can be reached at a desired distance or time, and POI2 must be reached at a desired distance or time. Means that the POI cannot. Therefore, POI1 is extracted as the corresponding POI.

  In FIG. 8, for the sake of explanation, the state where the corresponding POI in the service area polygon 81 is only POI1 is illustrated. However, when a plurality of corresponding POIs are extracted, each POI is extracted from the current position P as follows. The POIs can be sorted according to the route distance or time to the POI, and the POI list can be distributed and guided to the mobile terminal 20 in ascending order of the actual route distance or time from the current position.

  That is, the POI sorting unit 39 associates each POI extracted by the service area POI determination unit 38 as described above with the node in the service area polygon 81 that is closest to each other. FIG. 9 is a schematic diagram for explaining this process, and shows a state in which POIN is extracted in addition to POI 1 in the service area polygon in FIG. In FIG. 9, nodes N4 and N14 indicate nodes searched by the service area search of FIG.

  For POI1, node N14 is the closest node, and for POIN, node N4 is the closest node. This can be easily determined by comparing the position information of the node and the position information of each POI. Since each node is the result obtained by the service area search, the node potential represents the path distance or time from the current position to each node, and the node potential associated with each POI is the path to the POI. Approximate distance or time. Therefore, by sorting the POIs according to the potential of each node, the POIs can be arranged in ascending order of the route distance or time to each POI to obtain a search result.

  FIG. 10 distributes the POI search result obtained in this way to the portable terminal 20 and displays it on the display means 24. In FIG. 10A, POIs (in this case, “pharmacy”) are sorted and displayed in the order of closer route distance from the current position by the above processing. When the user selects and clicks the nearest pharmacy A on this screen, the screen transitions to the screen in FIG. 10B and the POI information related to pharmacy A is displayed. A hyperlink to the unit map data request including the POI on the display screen (character link of “display map” in FIG. 10B) and a hyperlink to the request for starting navigation (route guidance) (in FIG. 10B) Adding a “go here” text link) increases convenience. The user can request a map from the information distribution server 30 or request route guidance simply by selecting a desired POI and clicking these character links on the display screen of FIG. 10B.

  When a desired POI is selected on the POI search result answer screen shown in FIG. 10A, a navigation start hyperlink is operated on the POI information screen shown in FIG. 10B, and the information distribution server 30 requests route guidance to the POI. Since the node closest to this POI is associated, and this node has already been searched for the route from the current position in the service area search, the information distribution server 30 does not search for the route again. It can be distributed to the mobile terminal 20. That is, since the node closest to the POI is associated, the guide route from the current position to the node (POI) can be specified by following the link from the node in reverse.

  As a result of the search, when a sufficient POI is not searched, the input screen may be changed so that the search is performed again by changing the conditions (with longer walking time). At this time, since the calculation result of the service area search is saved, if the diffusion (route search) is performed from the continuation, the redundant calculation (route search) can be avoided.

  In addition, when map data is requested, the information distribution server can retrieve the relative relationship between the mesh in which the POI exists and the unit map, and distribute the map data of the corresponding area to the mobile terminal 20. If the unit map section and the mesh section are combined and the mesh number and the map number are the same, the map data of the corresponding area can be easily specified and distributed to the mobile terminal 20. Further, if the search network data 35 is also divided in the same unit as the mesh into which the unit map and the POI data are divided, the map data at the corresponding position from the identification code of the mesh that has reached the search for the service area and the link, The correspondence with the mesh of POI data can be immediately identified.

  FIG. 11 is a flowchart showing the above processing procedure. The information distribution server 30 first receives a POI search request from the portable terminal 20 in the process of step S10. This POI search request includes at least the current position of the mobile terminal 20, the POI category desired to be searched, and the service area (distance or time). This search request is analyzed in the process of step S11, and in the process of step S12, the route search means 33 performs a service area search according to the designation of the service area range. The service area search method is as described above.

  In the process of step S13, it is determined whether or not the service area search has been completed. If not, the process returns to the process of step S12 and the search is continued. If the service area search has been completed, the service area POI range determination means 36 determines a node in the service area and creates a service area polygon in the process of step S13. The method for creating service area polygons has also been described in detail earlier.

  Next, in the process of step S15, the service area POI determination means 38 extracts a mesh that overlaps the service area polygon and includes the POI that is included in the mesh (located within the mesh) and that exists within the service area polygon. Extract. The POI extracted in this process is a POI belonging to the category specified by the POI search condition. In the process of step S15, the service area POI determination means 38 determines, for each extracted POI, a node closest to the POI (a node in the service area polygon) and stores it in association with each POI.

In the process of step S16, it is determined whether all the above-mentioned service area POI determination processes have been completed. If the process has not been completed, the process returns to step S15 to continue the service area POI determination process, and the process ends. If so, the process proceeds to the POI sort process in step S17.
In the process of step S17, the POI sorting means 39 compares the potentials of the nodes associated with the POIs extracted in the process of step S15, and the path length (distance or distance) from the current position in ascending order of potential. Sort POI in ascending order of time. The sorted result, that is, the POI list (see FIG. 10A) searched and sorted by the processing of step S12 to step S17 is edited by the distribution data editing means 32 in the processing of step S18 and distributed to the portable terminal 20. .

  In the first embodiment, the example in which the service area POI determining unit extracts the POI in the service area polygon and associates the node in the nearest service area polygon with each extracted POI has been described. An embodiment like Example 2 can also be taken. The configuration of the navigation system of the second embodiment is the same as that of the first embodiment (FIG. 1), and the processing procedure is different. Assume that the POI category designated by the user is “pharmacy” as in the first embodiment.

  FIG. 12 is a flowchart of a POI search process procedure in the navigation system according to the second embodiment of the present invention. In FIG. 12, the processing procedure from step S20 to step S23 is the same as the processing procedure from step S10 to step S13 in FIG. When the service area search is completed in the process up to step S23, the process proceeds to step S24.

  In the process of step S24, the service area POI range determination means 36, unlike the process of step S14 of the first embodiment, does not create a service area polygon, and includes a mesh that includes nodes and links that have spread in the service area search. The service area POI range is specified by extracting the POI included in the mesh (located within the mesh). The POI extracted in this process is a POI (“pharmacy”) belonging to the category specified by the POI search condition.

  Thereafter, in the process of step S25, the service area POI discrimination means 38 finds the nearest link (the closest link by dropping a perpendicular from the POI to the nearest link) for each of the extracted POIs, and the link arrives. If it is a link (see FIG. 6) that has been searched (spread), it is regarded as a POI included in the service area, and if not, it is deleted from the extracted POI. Each POI thus narrowed down is stored in association with the nearest nearest link. If the link closest to the POI has not spread, the POI is discarded (deleted) from the extracted POI as not being in the service area.

  FIG. 13 is a schematic diagram showing the concept of this processing procedure. In FIG. 13, POI 4 and POI 5 are “pharmacies” that exist in the mesh specified by the service area POI range determination means 36, that is, the mesh that overlaps the range of the specific service area search. Take the nearest perpendicular from POI4 and POI5 and find the nearest link. Since the distance D4n of the perpendicular line dropped from POI4 to the link Ln and the distance D5m of the perpendicular line dropped from POI5 to the link Lm are the shortest, the nearest links are determined as Ln and Lm, respectively.

  The link Ln is a link that has undergone a service area search as indicated by a solid line, and the link Lm is a link that has not been reached by a service area search as indicated by a dotted line. Therefore, POI4 is extracted as a POI within the service area, and POI5 is excluded from the extracted POI as being outside the service area. The distance to the POI (path length) may be determined in detail in consideration of the length of the connected perpendicular and the distance to the link connection point. In some cases, there may be POIs that are far from the nearest link and do not meet the conditions. According to the processing method of the second embodiment, the verification can also be performed.

In the process of step S26, it is determined whether all the above-mentioned service area POI determination processes have been completed. If the process has not been completed, the process returns to step S25 to continue the service area POI determination process, and the process ends. If so, the process proceeds to the POI sort process in step S27.
In the process of step S27, the POI sorting means 39 calculates the path length or time based on the links associated with each POI extracted in the process of step S25, and in order of increasing path length or time, that is, The POIs are sorted in ascending order of the route length (distance or time) from the current position. Since the search for all nodes and links in the predetermined route range has been made by the service area search, the route length can be easily obtained using the result.

  As a result of the sorting by the POI sorting means 39, the POI list (see FIG. 10A) arranged in order of increasing path length or time is edited by the delivery data editing means 32 in the process of step S28 and delivered to the portable terminal 20. The The distribution result is the same as that described in the first embodiment with reference to FIG.

  In the first and second embodiments, the present invention has been described as a system using a mobile phone as a mobile terminal. However, the present invention can be applied to a stand-alone type car navigation system, a navigation system using a communication type mobile terminal, and the like. .

It is a figure which shows the structure of the POI information provision system concerning the Example of this invention. It is explanatory drawing which shows the data structure of the POI information accumulate | stored in POI category database (DB). It is a schematic diagram which shows the concept of the data of a road network. It is a schematic diagram which shows the concept of the data of a traffic network. It is a diagram showing a configuration of a service menu screen of the peripheral search in the mobile terminal of the present invention, It is a schematic diagram for demonstrating the concept of a service area search. It is a schematic diagram for demonstrating the concept of the polygon figure formation (a service area polygon) which comprises a service area. It is a schematic diagram for demonstrating the concept of the process which searches for the desired POI which exists in a service area polygon. It is a schematic diagram for demonstrating the concept of the process which sorts by several path | route distance or time about several POI which matches search conditions among POI in a service area polygon. FIG. 10A is a screen configuration diagram illustrating a configuration of a menu screen and a response screen for POI search in a mobile terminal, FIG. 10A is a menu screen, and FIG. 10B is a diagram illustrating a configuration of a response screen. It is a flowchart which shows the procedure of the POI search concerning Example 1 of this invention. It is a flowchart which shows the procedure of POI search concerning Example 2 of this invention. It is a schematic diagram for demonstrating the procedure of the service area POI discrimination | determination in Example 2 of this invention.

Explanation of symbols

10. Navigation system 11, 12. Network 20 ... Portable terminal 21 ... Control means 22 ... Communication means 23 ... Positioning means 24 ... Display means 25 ... ... delivery data storage means 26 ... delivery request editing means 27 ... operation / input means 30 ... information delivery server 31 ... control means 32 ... delivery data editing means 33 ··· Route search means 34 ··· Communication means 35 ··· Network data for search 36 ··· POI range determination means 37 ··· POIDB (database)
38 ··· POI discrimination means 39 ··· POI sorting means 50 ··· POI information providing server

Claims (22)

A POI database storing POI information including POI position information for each POI;
A search network database storing search network data composed of nodes and links;
Search condition setting means for setting a POI search condition including a reference position and a cost value for designating a range of a service area from the reference position;
A service area search means for performing a service area search search for tracing all nodes and links included in the service area that can be reached at the cost value or less by sequentially tracing the nodes from the reference position using the search network data;
Potential value holding means for holding a potential value that is a cumulative link cost for each node searched by the service area search means even after the service area search ;
POI extraction means for extracting a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
Corresponding means for associating one of the nodes or links searched by the service area searching means for each extracted POI with the POI closest to the extracted POI;
POI cost for generating a route distance or required time from the reference position to the POI with reference to the potential value held by the potential value holding unit based on the node or link associated by the association unit Information generating means;
A navigation system comprising: Sorting means for sorting the POIs based on potential values of nodes associated with each POI;
Output means for outputting POI information of the POI extracted by the POI extraction means based on the sort result;
The navigation system according to claim 1, further comprising:   The POI extracting means generates a polygon based on a node corresponding to the range of the service area among the nodes searched as the service area search result, and extracts a POI within the range of the polygon. The navigation system according to claim 1 or 2. The POI database stores the POI information in mesh units of a predetermined geographical area,
A mesh specifying means for specifying a mesh corresponding to the node searched by the service area search means;
4. The POI extraction unit further adds, as a POI extraction condition, that the POI position information is included in a mesh range specified by the mesh specification unit. The navigation system according to one item. The POI database holds the POI information for each category,
The search condition setting means includes a desired category in the POI search condition,
5. The navigation system according to claim 1, wherein the POI extraction unit further adds, as a POI extraction condition, a condition that matches a category included in the POI search condition. 6. Sorting means for sorting the POIs based on potential values of nodes connected to links associated with each POI;
Output means for outputting POI information of the POI extracted by the POI extraction means based on the sort result;
The navigation system according to claim 1, further comprising: The POI database stores the POI information in mesh units of a predetermined geographical area,
A mesh specifying means for specifying a mesh corresponding to the link searched by the service area search means;
The navigation system according to claim 6, wherein the POI extraction unit further adds, as a POI extraction condition, that the POI position information is included in a mesh range specified by the mesh specification unit. . The POI database holds the POI information for each category,
The search condition setting means includes a desired category in the POI search condition,
The navigation system according to claim 6 or 7, wherein the POI extraction unit further adds, as a POI extraction condition, that the category matches the category included in the POI search condition. A POI database storing POI information including POI position information for each POI;
A search network database storing search network data composed of nodes and links;
Search condition setting means for setting a POI search condition including a reference position and a cost value for designating a range of a service area from the reference position;
A service area search means for performing a service area search for tracing all nodes and links included in a service area that can be reached at the cost value or less by sequentially tracing the nodes from the reference position using the search network data;
Potential value holding means for holding a potential value that is a cumulative link cost for each node searched by the service area search means even after the service area search ;
POI extraction means for extracting a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
Corresponding means for associating one of the nodes or links searched by the service area searching means for each extracted POI with the POI closest to the extracted POI;
POI cost for generating a route distance or required time from the reference position to the POI with reference to the potential value held by the potential value holding unit based on the node or link associated by the association unit Information generating means;
A POI search method in a navigation system comprising:
A first step of searching for all nodes and links included in a service area that the service area search means sequentially traces the nodes from the reference position using the search network data and can be reached below the cost value;
A second step in which the POI extraction means extracts a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
A third step in which, for each POI extracted by the association means, one of the nodes or links closest to the extracted POI among the nodes or links searched by the service area searching means is associated with the POI;
The POI cost information generation unit refers to the potential value held by the potential value holding unit based on the node or link associated by the association unit, and the path distance from the reference position to the POI Or a fourth step of generating the required time, and
A POI search method comprising: The navigation system sorts the POI based on the potential value of the node associated with each POI, and outputs the POI information of the POI extracted by the POI extraction means based on the sorting result. And further comprising
In the fourth step, the sorting means sorts the POI based on the potential value of the node associated with each POI, and the output means extracts the POI POI extracted by the POI extracting means. The POI search method according to claim 9, further comprising a process of outputting information based on the sorting result.   The second step includes a process of generating a polygon based on a node corresponding to the range of the service area among the nodes searched as the service area search result, and extracting a POI within the range of the polygon. The POI search method according to claim 9 or 10. The POI database stores the POI information in mesh units of a predetermined geographical area,
The navigation system further comprises mesh specifying means for specifying a mesh corresponding to the node searched by the service area searching means,
12. The method according to claim 9, wherein the second step further adds, as a POI extraction condition, that the POI position information is included in the mesh range specified by the mesh specifying means. The POI search method according to claim 1. The POI database holds the POI information for each category,
The search condition setting means includes a desired category in the POI search condition,
13. The POI search method according to claim 9, wherein the POI extraction unit further adds, as a POI extraction condition, a condition that matches a category included in the POI search condition. 13. The navigation system sorts the POI based on a potential value of a node connected to a link associated with each POI, and the POI information of the POI extracted by the POI extraction unit based on the sorting result. And the output means for outputting, the fourth step, wherein the sorting means sorts the POI based on a potential value of a node connected to a link associated with each POI; 10. The POI search method according to claim 9, wherein the output means includes a process of outputting POI information of the POI extracted by the POI extraction means based on the sorting result. An information distribution server connected via a network to a portable terminal that transmits a POI search condition including a reference position and a cost value for designating a range of a service area from the reference position, the information distribution server Is
A POI database storing POI information including POI position information for each POI;
A search network database storing search network data composed of nodes and links;
A service area search means for performing a service area search for tracing all nodes and links included in a service area that can be reached at the cost value or less by sequentially tracing the nodes from the reference position using the search network data;
Potential value holding means for holding a potential value that is a cumulative link cost for each node searched by the service area search means even after the service area search ;
POI extraction means for extracting a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
Corresponding means for associating one of the nodes or links searched by the service area searching means for each extracted POI with the POI closest to the extracted POI;
POI cost for generating a route distance or required time from the reference position to the POI with reference to the potential value held by the potential value holding unit based on the node or link associated by the association unit Information generating means;
An information distribution server comprising: Sorting means for sorting the POIs based on potential values of nodes associated with each POI;
Output means for outputting POI information of the POI extracted by the POI extraction means based on the sort result;
The information distribution server according to claim 15, further comprising:   The POI extracting means generates a polygon based on a node corresponding to the range of the service area among the nodes searched as the service area search result, and extracts a POI within the range of the polygon. The information distribution server according to claim 15 or 16. The POI database stores the POI information in mesh units of a predetermined geographical area,
A mesh specifying means for specifying a mesh corresponding to the node searched by the service area search means;
18. The POI extraction unit further adds, as a POI extraction condition, that the POI position information is included in a mesh range specified by the mesh specification unit. The information distribution server according to one item. The POI database holds the POI information for each category,
The search condition setting means includes a desired category in the POI search condition,
The information distribution server according to any one of claims 15 to 18, wherein the POI extraction unit further adds, as a POI extraction condition, that the category matches the category included in the POI search condition. Sorting means for sorting the POIs based on potential values of nodes connected to links associated with each POI;
Output means for outputting POI information of the POI extracted by the POI extraction means based on the sort result;
The information distribution server according to claim 15, further comprising: The POI database stores the POI information in mesh units of a predetermined geographical area,
A mesh specifying means for specifying a mesh corresponding to the link searched by the service area search means;
21. The information distribution according to claim 20, wherein the POI extraction unit further adds, as a POI extraction condition, that the POI position information is included in a mesh range specified by the mesh specification unit. server. A POI database storing POI information including POI position information for each POI;
A search network database storing search network data composed of nodes and links;
Based on a POI search condition including a reference position and a cost value for designating a range of service area from the reference position, the cost value is obtained by sequentially tracing nodes from the reference position using the search network data. A service area search means for performing a service area search for searching all nodes and links included in the service area that can be reached below;
Potential value holding means for holding a potential value that is a cumulative link cost for each node searched by the service area search means even after the service area search ;
POI extraction means for extracting a POI in which the POI position information is included in a range formed based on either the node or the link searched by the service area search means;
Corresponding means for associating one of the nodes or links searched by the service area searching means for each extracted POI with the POI closest to the extracted POI;
POI cost for generating a route distance or required time from the reference position to the POI with reference to the potential value held by the potential value holding unit based on the node or link associated by the association unit Information generating means;
A portable terminal connected to an information distribution server comprising a network,
A mobile terminal comprising: search condition setting means for setting a POI search condition including the reference position and a cost value for designating a range of a service area from the reference position.

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