JP4568754B2 - Route search device, route search method, route search program, and recording medium - Google Patents

Description

【Technical field】
[0001]
The present invention relates to a route search device, a route search method, a route search program, and a recording medium that search for a route to a destination point. However, the use of the present invention is not limited to the above-described route search device, route search method, route search program, and recording medium.
[Background]
[0002]
Conventionally, in a route search performed in car navigation or the like, various routes from a departure point to a destination point are evaluated using information of each point stored in advance. Then, the route having the best evaluation among these routes is selected as the optimum route, and the selected optimum route is displayed as the traveling route (see, for example, Patent Document 1 below).
[0003]
When evaluating a route for selecting an optimal route in this way, for example, the ease of passing each link is estimated using parameters such as road type and width, link travel time included in VICS information, and the cost of the link. Is calculated. Then, the route having the minimum accumulated cost is selected as the optimum route.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 06-309595
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0005]
However, according to the above-described prior art, although the type of road (for example, an expressway, a toll road, a general road, etc.) and the width can be considered, the actual usage situation of the road can be considered. There wasn't. For example, commercial areas such as shopping streets and suburban roads differ greatly in the way they are used, and the congestion situation also differs. For this reason, the problem that the selected route may not always be optimal in accordance with the actual road condition is given as an example.
[0006]
Another example is the problem of acquiring traffic information such as VICS information that can be obtained in real time, so that a traffic jam on the road can be known in real time, but a dedicated device is required to acquire the information. . Furthermore, the problem that it cannot cope with the area where information is not supplied is mentioned as an example.
Means for solving the problem
[0007]
In order to solve the above-described problems and achieve the object, the route search device according to the invention of claim 1 includes facility number information acquisition means for acquiring information related to the number of facilities around the link from address information around the link; An evaluation unit that evaluates each of the links based on information on the number of facilities acquired by the facility number information acquisition unit, and a search unit that selects a link highly evaluated by the evaluation unit and searches for a route to a destination point And.
[0008]
Further, the route search method according to the invention of claim 6 is a route search method in the route search device, the facility number information acquisition step of acquiring information on the number of facilities around the link from the address information around the link; An evaluation step for evaluating each of the links based on information on the number of facilities acquired by the facility number information acquisition step, and a search step for searching for a route to a destination point by selecting a link that is highly evaluated by the evaluation step It is characterized by including these.
[0009]
A route search program according to a seventh aspect of the invention causes a computer to execute the route search method according to the sixth aspect.
[0010]
A recording medium according to an eighth aspect of the present invention is readable by a computer in which the route search program according to the seventh aspect is recorded.
[Brief description of the drawings]
[0011]
FIG. 1 is a block diagram of a functional configuration of a route search apparatus according to an embodiment.
FIG. 2 is a flowchart showing a procedure of route search processing by the route search device.
FIG. 3 is a block diagram of an example of a hardware configuration of the navigation device according to the embodiment.
[FIG. 4] FIG. 4 is a flowchart illustrating an example of route search processing performed by a route search unit.
FIG. 5 is a flowchart illustrating an example of a link cost calculation process performed by the route search unit.
FIG. 6 is a flowchart illustrating an example of a link cost calculation process performed by a route search unit;
FIG. 7 is a flowchart illustrating an example of link cost calculation processing performed by a route search unit;
FIG. 8 is a diagram illustrating an example of a route searched by a route search unit.
[Explanation of symbols]
[0012]
100 route search device
101 Number of facilities information acquisition part
102 Evaluation Department
103 Search unit
104 Customer information acquisition department
105 Genre information acquisition unit
BEST MODE FOR CARRYING OUT THE INVENTION
[0013]
Exemplary embodiments of a route search device, a route search method, a route search program, and a recording medium according to the present invention will be explained below in detail with reference to the accompanying drawings.
[0014]
(Embodiment)
(Functional configuration of route search apparatus 100)
FIG. 1 is a block diagram of a functional configuration of the route search apparatus according to the embodiment. The route search apparatus 100 according to the embodiment includes a facility number information acquisition unit 101, an evaluation unit 102, a search unit 103, a customer information acquisition unit 104, and a genre information acquisition unit 105.
[0015]
The facility number information acquisition unit 101 acquires information related to the number of facilities around the link. A link is a minimum structural unit of a road on map information. The facility number information acquisition unit 101 acquires information on the number of facilities per unit length of the link, for example. Acquisition of information regarding the number of facilities is performed, for example, by extracting the number of facilities facing the link from the map information. Moreover, you may make it acquire the information regarding the number of facilities around a link from the address information around a link.
[0016]
The evaluation unit 102 evaluates the link based on information on the number of facilities acquired by the facility number information acquisition unit 101. Based on information on the number of facilities, for example, is to give a high evaluation to a link with a small number of facilities per unit length. The link is evaluated by, for example, calculating a value called cost for each link.
[0017]
The search unit 103 selects a link highly evaluated by the evaluation unit 102 and searches for a route to the destination point. By selecting a link with a high evaluation by the evaluation unit 102, for example, a link with a small number of facilities per unit length can be selected to search for a route to the destination point.
[0018]
The customer collection information acquisition unit 104 acquires information related to the ability to attract customers of facilities around the link. The facility for attracting customers is evaluated by, for example, the area of the facility, the genre, and the number of parking lots. In addition, the customer information acquisition unit 104 may acquire information regarding the ability to attract customers by time zone of the facility.
[0019]
When the customer information acquisition unit 104 acquires information related to the ability to attract customers in the facilities around the link, the evaluation unit 102 gives a low evaluation to a link in the vicinity of a facility that has a high ability to attract customers. Further, when information about the ability to attract customers by time zone of the facility is acquired, the evaluation unit 102 gives a low evaluation to a link in the vicinity of a facility in a time zone where the ability to attract customers is high.
[0020]
The genre information acquisition unit 105 acquires information related to the genre of the facility around the link. The information on the genre of the facility is, for example, information on what genre the facility belongs to. When the genre information acquisition unit 105 acquires information related to the genre of the facility around the link, the customer acquisition information acquisition unit 104 acquires information related to the ability to attract customers for each genre of the facility. And the evaluation part 102 gives low evaluation to the link in which the facility of the genre with high customer attraction ability exists in the periphery.
[0021]
(Route Search Processing Procedure by Route Search Device 100)
FIG. 2 is a flowchart showing a procedure of route search processing by the route search device. First, the route search device 100 uses the facility number information acquisition unit 101 to acquire information regarding the number of facilities around the link (step S201). At this time, the link for acquiring information on the number of surrounding facilities is, for example, the link closest to the starting point or the current point of the route to be searched.
[0022]
Next, the customer information acquisition unit 104 acquires information related to the ability to attract customers in the facilities around the link (step S202). Further, the genre information acquisition unit 105 acquires information related to the genre of the facility around the link (step S203). Then, the link is evaluated by the evaluation unit 102 from the information acquired in steps S201 to S203 (step S204).
[0023]
The search unit 103 determines whether to include the link in the route to the destination point based on the evaluation performed by the evaluation unit 102 in step S204 (step S205). Specifically, for example, a link with a high evaluation by the evaluation unit 102 is included in the route to the destination point, and a link with a low evaluation is not included in the route.
[0024]
If not included in the route to the destination point (step S205: No), the process proceeds to step S207. On the other hand, if it is included in the route to the destination point (step S205: Yes), a link is added to the route (step S206), and it is determined whether the destination point has been reached (step S207). If the destination point has been reached (step S207: Yes), the processing according to this flowchart is terminated. On the other hand, when the destination point has not been reached (step S207: No), another link is searched (step S208), the process returns to step S201, and the subsequent processing is repeated.
[0025]
As described above, the route search apparatus 100 searches for a route in consideration of the number of facilities around the link and the genre of the facility. The facilities around the link are largely related to the link traffic. Therefore, it is possible to search for a route that is more realistic. Further, a dedicated device is not required unlike a device that sequentially acquires VICS information and the like.
[0026]
In the above embodiment, the search unit 103 includes, based on the evaluation performed by the evaluation unit 102, a link with a high evaluation included in the route to the destination, and a link with a low evaluation is not included in the route. For example, it is conceivable to evaluate a route step by proceeding for a plurality of links, such as searching for a plurality of routes at the same time or determining the cost of the entire route. In that case, even if the evaluation is low in the comparison with the link alone, it may be included in the route.
【Example】
[0027]
(Hardware configuration of navigation device 300)
FIG. 3 is a block diagram illustrating an example of a hardware configuration of the navigation device according to the embodiment. First, the hardware configuration of the navigation device 300 according to the embodiment will be described. The navigation device 300 searches for a route from the departure point to the destination point using the route search device 100 according to the embodiment, and guides the user's vehicle along the searched route.
[0028]
In FIG. 3, the navigation device 300 is mounted on a vehicle, and includes a navigation control unit 301, a user operation unit 302, a display unit 303, a position acquisition unit 304, a recording medium 305, and a recording medium decoding unit 306. , A guidance sound output unit 307, a communication unit 308, a route search unit 309, a route guidance unit 310, a guidance sound generation unit 311, and a speaker 312.
[0029]
The navigation control unit 301 controls the entire navigation device 300. The navigation control unit 301 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) that stores various control programs, and a RAM (Random Access Memory) that functions as a work area of the CPU. It is realizable with the microcomputer etc. comprised by these.
[0030]
The navigation control unit 301 uses a map on the map based on information on the current position acquired by the position acquisition unit 304 and map information obtained from the recording medium 305 via the recording medium decoding unit 306 at the time of route guidance. It calculates which position the vehicle is traveling and outputs the calculation result to the display unit 303. In addition, the navigation control unit 301 inputs / outputs information regarding route guidance to / from the route search unit 309, the route guidance unit 310, and the guidance sound generation unit 311 when performing route guidance, and displays information obtained as a result thereof. And output to the guide sound output unit 307.
[0031]
The user operation unit 302 outputs information input by the user, such as characters, numerical values, and various instructions, to the navigation control unit 301. As the configuration of the user operation unit 302, various known forms such as a push button switch that detects physical pressing / non-pressing, a touch panel, a keyboard, and a joystick can be employed. The user operation unit 302 may be configured to perform an input operation by sound using a microphone that inputs sound from the outside.
[0032]
The user operation unit 302 may be provided integrally with the navigation device 300, or may be configured to be operated separately from the navigation device 300 like a remote controller. The user operation unit 302 may be configured in any one of the various forms described above, or may be configured in a plurality of forms. The user inputs information by appropriately performing an input operation according to the form of the user operation unit 302. Examples of information input by the operation of the user operation unit 302 include a destination point or a departure point of a route to be searched.
[0033]
The destination or departure point can be entered by entering the latitude / longitude and address of each point, as well as specifying the phone number, genre, keyword, etc. of the facility that will be the destination or departure point. The position can be specified. More specifically, these pieces of information are specified as a point on the map based on background type data included in map information recorded on the recording medium 305 described later. Further, map information may be displayed on the display unit 303 described later, and one point on the displayed map may be designated.
[0034]
Further, a touch panel can be adopted as the form of the user operation unit 302. When a touch panel is employed, the touch panel is used by being stacked on the display surface side of the display unit 303. The input information is recognized by managing the display timing on the display unit 303, the operation timing on the touch panel (user operation unit 302), and the position coordinates thereof. By adopting a touch panel stacked on the display unit 303 as a form of the user operation unit 302, a large amount of information can be input without increasing the size of the form of the user operation unit 302. As the touch panel, various known touch panels such as a resistance film type and a pressure sensitive type can be used.
[0035]
The display unit 303 includes, for example, a CRT (Cathode Ray Tube), a TFT liquid crystal display, an organic EL display, a plasma display, and the like. Specifically, the display unit 303 can be configured by, for example, a video display device connected to the video I / F or the video I / F. Specifically, the video I / F includes, for example, a graphic controller that controls the entire display device, a buffer memory such as a VRAM (Video RAM) that temporarily stores image information that can be displayed immediately, and a graphic controller. Based on the output image information, it is configured by a control IC for controlling display of the display device. The display unit 303 displays various information such as icons, cursors, menus, windows, or characters and images. The display unit 303 displays map information stored in the HD and information related to route guidance.
[0036]
The position acquisition unit 304 acquires the current position of the own device. Here, the current position of the device itself is obtained by receiving a radio wave from a GPS satellite and obtaining a geometric position with respect to the GPS satellite, and can be measured anywhere on the earth. GPS is an abbreviation for Global Positioning System, and is a system for accurately obtaining a position on the ground by receiving radio waves from four or more satellites. The position acquisition unit 304 can be configured by, for example, an antenna for receiving radio waves from GPS satellites, a tuner that demodulates the received radio waves, and an arithmetic circuit that calculates the current position based on the demodulated information.
[0037]
As a radio wave from the GPS satellite, an L1 radio wave carrying a C / A (Coarse and Access) code and a navigation message with a carrier wave of 1.57542 GHz is used. Thereby, the current position (latitude and longitude) of the own apparatus is detected. In detecting the current position of the device itself, information collected by various sensors such as a vehicle speed sensor and a gyro sensor may be taken into consideration. The vehicle speed sensor detects from the output side shaft of the transmission of the vehicle on which the navigation device 300 is mounted.
[0038]
In addition, when acquiring the current position of the device itself, information collected by various sensors such as an angular velocity sensor, a travel distance sensor, and an inclination sensor may be taken into consideration. The angular velocity sensor detects an angular velocity when the host vehicle rotates and outputs angular velocity information and relative orientation information. The travel distance sensor calculates the number of pulses per one rotation of the wheel by counting the number of pulses of a pulse signal with a predetermined period that is output with the rotation of the wheel, and travel distance information based on the number of pulses per one rotation Is output. The inclination sensor detects the inclination angle of the road surface and outputs inclination angle information.
[0039]
The recording medium 305 records various control programs and various information in a state readable by a computer. The recording medium 305 accepts writing of information by the recording medium decoding unit 306 and records the written information in a nonvolatile manner. The recording medium 305 can be realized by, for example, HD (Hard Disk). The recording medium 305 is not limited to the HD, and can be attached to and detached from the recording medium decoding unit 306 such as a DVD (Digital Versatile Disk) or a CD (Compact Disk) instead of or in addition to the HD. A medium having portability may be used as the recording medium 305. The recording medium 305 is not limited to a DVD and a CD, but can be attached to and detached from a recording medium decoding unit 306 such as a CD-ROM (CD-R, CD-RW), MO (Magneto-Optical disk), or memory card. Media with portability can also be used.
[0040]
The recording medium 305 in this embodiment records a navigation program, map information, and the like that realize the present invention. The map information includes background data representing features (features) such as buildings, rivers, and the ground surface, and road shape data representing road shapes, and is displayed on the display screen of the display unit 303 in two dimensions or three dimensions. Drawn on.
[0041]
The background data includes background shape data representing the shape of the background and background type data representing the type of the background. The background shape data includes, for example, feature representative points, polylines, polygons, feature coordinates, and the like. The background type data includes, for example, text data representing the name, address, and telephone number of a feature, and type data of a feature such as a building, river, or ground surface.
[0042]
In addition, as for the major facilities (POI: Point of Interest) in the map, information such as business hours and the presence / absence of a parking lot is included as facility information. Furthermore, among the features, facilities provided for a predetermined purpose, such as “gas station” and “convenience store”, are classified according to their types. Then, the representative point and coordinate data of the feature and the facility information / genre information are associated with each other. The genre into which the facility is classified at this time includes, for example, a parking lot and a station in addition to the above-mentioned gas station and convenience store.
[0043]
Next, the road shape data is a road network having a plurality of nodes and links connecting the nodes. The node indicates an intersection where a plurality of roads such as a three-way road such as a T-shaped road, a cross road, and a five-way road intersect. The link indicates a road. Some links have shape interpolation points, and curved roads can be expressed by these shape interpolation points.
[0044]
Each link is associated with facility information of a facility facing or around the link, and the number and genre of facilities facing the link can be known. In addition, you may make it search the facility in the vicinity from the position (coordinate) of a link instead of performing association with a link and facility information beforehand.
[0045]
The road shape data further includes traffic condition data. The traffic condition data includes, for example, the presence or absence of signals and pedestrian crossings, the presence or absence of entrances and junctions of highways, the length (distance) of each link, vehicle width, traveling direction, road type (highway) , Toll roads, general roads, etc.). The traffic condition data stores past traffic information obtained by statistically processing past traffic information based on seasons, days of the week, large holidays, and time. The navigation device 300 obtains information on a traffic jam that is currently occurring from the road traffic information received by the communication unit 308, and can predict a traffic jam situation at a specified time by using the past traffic jam information.
[0046]
In this embodiment, the map information is recorded on the recording medium 305. However, the present invention is not limited to this. The map information is not recorded only on the one integrated with the hardware of the navigation device 300, and may be provided outside the navigation device 300. In that case, the navigation apparatus 300 acquires map information via a network through the communication unit 308, for example. The acquired map information is stored in a RAM or the like.
[0047]
The recording medium decoding unit 306 controls reading / writing of information with respect to the recording medium 305. For example, when HD is used as a recording medium, the recording medium decoding unit 306 is an HDD (Hard Disk Drive). Similarly, when a DVD or CD (including CD-R and CD-RW) is used as a recording medium, the recording medium decoding unit 306 is a DVD drive or a CD drive. When a CD-ROM (CD-R, CD-RW), MO, memory card, or the like is used as the writable and detachable recording medium 305, information is written into various recording media and stored in various recording media. A dedicated drive device that can read the recorded information is appropriately used as the recording medium decoding unit 306.
[0048]
The guide sound output unit 307 reproduces the guide sound by controlling the output to the connected speaker 312. There may be one speaker 312 or a plurality of speakers 312. Specifically, the guidance sound output unit 307 can be realized by an audio I / F connected to an audio output speaker 312. More specifically, the audio I / F includes, for example, a D / A converter that performs D / A conversion of audio digital information, an amplifier that amplifies an audio analog signal output from the D / A converter, and audio analog information. And an A / D converter that performs A / D conversion.
[0049]
The communication unit 308 acquires road traffic information such as traffic jams and traffic regulations regularly (or even irregularly). The communication unit 308 is connected to a network and transmits / receives information to / from other devices connected to the network.
[0050]
The reception of the road traffic information by the communication unit 308 may be performed at the timing when the road traffic information is distributed from the VICS (Vehicle Information and Communication System) center, or the road traffic information is periodically requested from the VICS center. You may go on. Moreover, you may make it acquire the road traffic information of a desired area via a network from the VICS information of the whole country collected by the server. The communication unit 308 can be realized by, for example, an FM tuner, a VICS / beacon receiver, a wireless communication device, and other communication devices.
[0051]
Detailed description is omitted because it is a well-known technology, but “VICS” is a vehicle-mounted device such as a car navigation device that transmits road traffic information such as traffic jams and traffic regulations edited and processed at the VICS Center in real time. It is an information communication system that displays characters and figures. As a method of transmitting road traffic information (VICS information) edited and processed at the VICS center to the navigation device 300, there is a method of using “beacon” and “FM multiplex broadcasting” installed on each road. “Beacons” include “radio wave beacons” mainly used on expressways and “optical beacons” used on major general roads. When “FM multiplex broadcasting” is used, road traffic information in a wide area can be received. When using a “beacon”, it is possible to receive necessary road traffic information at a location where the vehicle is located, such as detailed information on the most recent road based on the vehicle location.
[0052]
The route search unit 309 searches for an optimum route from the departure point to the destination point using map information stored in the recording medium 305, VICS information acquired via the communication unit 308, and the like. Here, the optimum route is a route that best matches the condition specified by the user. In general, there are an infinite number of routes from a departure point to a destination point. For this reason, items considered in route search are set to search for a route that matches the condition. Items to be considered at this time (hereinafter referred to as search conditions) include, for example, the required time to the destination point, the type of road (highway priority, general road priority, etc.), distance, and charge.
[0053]
The route search unit 309 calculates the cost for each link, which is the minimum road unit on the map information, and presents the route with the lowest accumulated cost to the user as the recommended route. Here, the cost is an index for evaluating each route by quantifying elements provided in a route that is generally determined as an “optimum route”. For example, factors such as the degree of traffic congestion, straightness, charge, number of right (left) turns, width, etc. are evaluated numerically. Then, the integrated cost is calculated by weighting each element with a coefficient and adding them together.
[0054]
Further, as described above, when searching for a route, search conditions such as road type, distance, and fee can be set by the user. The route search unit 309 changes the value of the weighting coefficient of each element according to the search condition set by the user, varies the accumulated cost even for the same route, and performs route search according to the setting of the search condition.
[0055]
Further, the route search unit 309 performs a route search in accordance with the actual situation by calculating the cost of the link based on the number of facilities around the link. In general route search, the ease of linking is estimated based on the road type, width, link travel time included in the VICS information, etc., and is used as the cost of the link at the time of route calculation. In addition to this, the route search unit 309 estimates the number of facilities around the link per unit length from the ratio of the number of POIs (Point of Interest) associated with the link and the link length.
[0056]
This is because roads with more facilities in the vicinity are more likely to use pedestrians and other vehicles and take longer to travel. Further, when the type of POI is a store or more occupies a certain level or more, it can be inferred that the link is a shopping street, and there is a high possibility that it takes time to travel. As described above, it is not always possible to know the actual state of the road only by factors such as the road type, the width, or the link travel time included in the VICS information. In particular, it is difficult to distinguish between busy downtown roads and empty suburban roads. For this reason, the cost of a link can be calculated based on the number of facilities around the link, and a more realistic route can be presented to the user.
[0057]
As the departure point of the route searched by the route search unit 309, the current position acquired by the position acquisition unit 304 or the departure point designated by the user from the user operation unit 302 is set. In addition to the destination point input by the user, the facility searched from the map data by genre search or the like may be set as the destination point.
[0058]
Returning to the description of FIG. 3, the route guidance unit 310 includes information related to the guidance route searched by the route search unit 309, or route information received by the communication unit 308 and information related to the current position acquired by the position acquisition unit 304. On the basis of the map information obtained from the recording medium 305 via the recording medium decoding unit 306, real-time route guidance information is generated. The route guidance information generated by the route guidance unit 310 is output to the display unit 303 via the navigation control unit 301.
[0059]
The guide sound generator 311 generates tone and voice information corresponding to the pattern. That is, based on the route guidance information generated by the route guidance unit 310, the virtual sound source corresponding to the guidance point is set and the voice guidance information is generated, and this is sent to the guidance sound output unit 307 via the navigation control unit 301. Output.
[0060]
The facility number information acquisition unit 101, the evaluation unit 102, the search unit 103, the customer information acquisition unit 104, and the genre information acquisition unit 105, which are functional configurations of the route search apparatus 100 according to the embodiment, are the route search unit 309. The function is realized by.
[0061]
(Route search processing by the route search unit 309)
FIG. 4 is a flowchart illustrating an example of route search processing performed by the route search unit. Here, details of the route search processing performed by the route search unit 309 will be described. The processing shown below is a route search method generally called the Dijkstra method. When the user starts a route search by designating a departure point and a destination point, the route search process shown in FIG. 4 is started. In the following description, only the route search from the departure point is shown for convenience of description, but the same processing is performed from the destination point in parallel to shorten the time required for the route search processing. Yes.
[0062]
First, a link (road) closest to the departure point is added as a candidate (step S401). Here, the term “candidate” refers to a candidate link that becomes a part of a route to be finally searched. In addition, “closest” means that, in addition to the link facing the departure point, if there is a link within a certain range centered on the specified departure point, that link is added to the candidate. .
[0063]
Next, it is determined whether there are one or more candidate links (step S402). When there are one or more candidates (step S402: Yes), that is, when there is a link around the departure point, the link with the lowest accumulated cost (hereinafter referred to as link L) is selected from the candidates (hereinafter referred to as link L) ( Step S403). The integrated cost is an integrated value of the cost of each link calculated in step S408 described later.
[0064]
On the other hand, in step S402, when there is no candidate (step S402: No), that is, when there is no road in the vicinity (for example, when the ocean is designated as a departure point), the search is failed (step S404). Then, the process according to this flowchart is terminated.
[0065]
Next, in step S403, the link L is selected, and when the link L reaches the destination point (step S405: Yes), the search is terminated (step S406), and the processing according to this flowchart is terminated. On the other hand, when the link L has not reached the destination point (step S405: No), one of the other links connected to the link L (hereinafter referred to as the link Cn (n = 1, 2, 3,...)). Is added as a candidate (step S407). Whether or not the link Cn is added as a candidate is determined based on whether the link Cn conforms to road traffic conditions such as road closures and time restrictions, and search conditions such as road type and fee.
[0066]
And when not adding to a candidate (step S407: No), it transfers to step S409. On the other hand, when adding to a candidate (step S407: Yes), the cost of the link Cn is calculated and added to the candidate (step S408). As described above, in the route search apparatus according to the present embodiment, in addition to factors such as the degree of congestion of the link, straightness, fee, right (left) number of turns, width, etc., the link is based on the number of facilities per link length. The cost is calculated. Details of the cost calculation process performed at this time will be described later.
[0067]
Next, it is determined whether there is another link Cn + 1 connected to the link L (step S409). If there is another link Cn + 1 (step S409: Yes), the link Cn + 1 is replaced with the link Cn (step S410), the process returns to step S405, and the subsequent processing is repeated. On the other hand, if there is no other link Cn + 1 (step S409: No), the candidate link Cn is replaced with the link L (step S411), the process returns to step S402, and the subsequent processing is repeated.
[0068]
In the above embodiment, the basic concept is shown in which the link with the lowest cost is added to the candidate. However, for example, it is also possible to evaluate the accumulated cost after a search for a plurality of links is advanced. It is done. In that case, the comparison with the link alone may be added to the candidate even if the cost is high.
[0069]
By repeating the above processing, a route from the departure point to the destination point is searched. In addition, the above processing is performed in parallel from the starting point and the destination point, and the candidate links are prevented from spreading indefinitely, and the time required for route search is shortened.
[0070]
(Details of link cost calculation process)
Next, the details of the link cost calculation process performed in step S408 of FIG. 4 will be described. As described above, the route search unit 309 calculates the cost of a link when searching for a route, and presents a route according to the user's wishes among a myriad of routes from a departure point to a destination point. Factors generally considered in calculating the cost of this link include the degree of traffic congestion, straightness, fee, right (left) number of turns, width, and the like.
[0071]
In addition to these, the route search unit 309 uses the number of facilities existing around the link as an element for cost calculation. Thereby, the route search can be performed in consideration of the actual situation of the road that cannot be known from the map information or the average travel time. Furthermore, the actual situation of the road can be predicted with higher accuracy by adjusting the cost according to the type of facility and the business hours.
[0072]
FIG. 5 is a flowchart illustrating an example of a link cost calculation process performed by the route search unit. First, the route search unit 309 performs normal link cost calculation based on factors such as the degree of congestion of the link, straightness, charge, number of right (left) turns, width, etc. (step S501). Next, link length information of the link is acquired (step S502). The link length is the length (distance) of the link, and the acquisition of the link length information is performed by extracting from the map information recorded on the recording medium 305.
[0073]
Subsequently, the route search unit 309 extracts the number of facilities around the link (step S503). The facility around the link may be a facility located within a certain distance from the link in addition to the facility facing the link. When the POI information is associated with the link in advance, the route search unit 309 extracts the number of facilities associated with the link from the map information stored in the recording medium 305. If POI information is not associated with the link in advance, the number of facilities in the vicinity is extracted from the link position information.
[0074]
Further, the number of facilities acquired in step S503 is divided by the link length acquired in step S502 (number of facilities / link length) to calculate the number of facilities per unit length of the link (step S504). The value calculated at this time becomes larger as the facilities are densely packed, and the value is small when there are few facilities.
[0075]
Then, a cost corresponding to the value calculated in step S504 is added to the cost calculated by the cost calculation in step S501 (step S505). The cost added here increases as the value calculated in step S504 increases. This is because an area where facilities are densely populated is expected to have a large number of passers-by and traffic vehicles, and it will take a long time to pass. Up to this point, the number of facilities existing around the link is used as a cost calculation element. In the following steps, the cost is further adjusted according to the type of facility and business hours.
[0076]
First, the route search unit 309 searches the map information recorded in the recording medium 305, and determines whether there is facility information of facilities around the link (step S506). When there is no facility information of the facility around the link (or when there is no facility around the link) (step S506: No), the processing according to this flowchart is terminated without adding the cost.
[0077]
On the other hand, if there is facility information of the facility around the link (step S506: Yes), it is determined from the business time information included in the facility information whether the current time is within the business hours of the facility (step S507). This is because if the current time is outside business hours, the link is considered not to be congested even around the facility. At this time, when it is predicted that the shop is congested before and after opening or closing, determination may be made by regarding a certain time before and after business hours as business hours. Further, when congestion is expected in a predetermined time zone, it may be determined whether the current time is included in the time zone.
[0078]
If the current time is within the business hours of the facility (step S507: Yes), it is determined whether the facility is a genre facility with a high degree of customer attraction (step S508). Generally, facilities attract customers differently depending on the genre. For example, it is considered that small-scale stores are less attracting customers than large-scale commercial facilities. In this way, the degree of attracting customers is set for each genre of facility, and is used as an index for measuring the degree of congestion around the facility.
[0079]
When the facility is a genre with a high degree of attracting customers (step S508: Yes), a high cost is added (step S509). On the other hand, if the facility is not a genre with a high degree of attracting customers (step S508: No), or if it is not within the business hours of the facility in step S507 (step S507: No), a low cost is added (step S510). The cost to be added at this time may be set stepwise in accordance with the degree of attracting customers and the deviation from business hours.
[0080]
Then, it is determined whether the processing has been completed for all facilities around the link (step S511). If the processing has been completed (step S511: Yes), the processing according to this flowchart is terminated. On the other hand, if not completed (step S511: No), the process returns to step S507, and the subsequent processing is repeated.
[0081]
As described above, the route search unit 309 uses the number of facilities existing around the link as a cost calculation element in addition to a general cost calculation element. Thereby, the route search can be performed in consideration of the actual situation of the road that cannot be known from the map information or the average travel time. In the navigation device 300, the VICS information is acquired by the communication unit 308, but the roads on which the VICS information is provided are limited. In this way, by using the facility information included in the map information, it is possible to predict the congestion state of the road even on the road where the VICS information is not provided.
[0082]
Furthermore, by using the facility information included in the map information, the cost can be adjusted according to the type of facility and the business hours provided around the link, and a more realistic road situation can be predicted. In addition, in the case where there is information regarding a matter that affects the degree of attracting customers for facilities around the link, the cost may be calculated in consideration of the matter. For example, according to the public schedule of a theater or a movie theater, the time zone when the audience returns home is set high.
[0083]
If the map information includes information indicating the number of facilities around the link, the link cost may be calculated using the information. Thereby, the outline of the traffic situation of the link can be known without searching for facilities around the link. For example, address range information is an example of information indicating the number of facilities around a link.
[0084]
The address range information is information (address information) indicating the address of the building facing the link. In Europe and the United States, the address is displayed by the street name and address. As a general rule, the street address is assigned to each building in order from the end of the street. For this reason, it is possible to know the approximate number of buildings on the street from the street address information. By using this, the degree of congestion of the link can be estimated and reflected in the cost of the link.
[0085]
FIG. 6 is a flowchart illustrating an example of a link cost calculation process performed by the route search unit. First, the route search unit 309 performs normal link cost calculation based on factors such as the degree of congestion of the link, straightness, charge, number of right (left) turns, width, and the like (step S601). Next, it is determined whether there is address range information associated with the link (step S602). Specifically, for example, it is searched whether the map information recorded on the recording medium 305 includes address range information.
[0086]
If there is address range information associated with the link (step S602: Yes), the address range information is acquired (step S603). Then, a value obtained by multiplying the number of address ranges and the unit cost (the number of address ranges × unit cost) is added to the cost calculated by the cost calculation in step S601 (step S604), and the processing according to this flowchart ends. Here, the unit cost is a conversion coefficient used when converting the number of address ranges into a cost. Also, the number of facilities per unit length may be calculated by dividing the number of address ranges by the link length, and multiplied by the unit cost. On the other hand, when there is no address range information associated with the link (step S602: No), the processing according to this flowchart is terminated without adding the cost.
[0087]
As explained above, when there is information in the map information that can be used to estimate the number of facilities around the link, such as address range information, the cost should be calculated considering the traffic situation of the link using this information. Can do. At this time, the cost to be added may be varied depending on the genre of the facility around the link.
[0088]
Furthermore, when there is a certain genre facility around the link, the cost of the link may be increased. For example, if there is a certain ratio of commercial facilities around the link, the link is likely to be a shopping street. As described above, it is possible to determine whether or not there is a certain genre of facility or more, thereby determining the ease of passage of the link and reflecting it in the cost of the link.
[0089]
FIG. 7 is a flowchart illustrating an example of a link cost calculation process performed by the route search unit. First, the route search unit 309 performs a normal link cost calculation based on factors such as the degree of congestion of the link, straightness, charge, number of right (left) turns, width, etc. (step S701). Next, the route search unit 309 acquires link length information of the link (step S702).
[0090]
Subsequently, the genre information of the facility around the link is acquired (step S703), and the number of commercial facilities around the link is extracted from the acquired genre information (step S704). Then, it is determined whether the value (number of commercial facilities / link length) obtained by dividing the number of facilities extracted in step S704 by the link length acquired in step S702 is equal to or greater than a certain value (step S705). The value calculated at this time becomes larger as the commercial facilities are densely linked.
[0091]
When the number of commercial facilities / link length is equal to or greater than a certain value (step S705: Yes), the link is determined to be a shopping street, and the cost calculated by the cost calculation in step S701 is multiplied by a predetermined coefficient (step S706). ), The process according to this flowchart is terminated. In addition to multiplying by a predetermined coefficient, a predetermined cost may be added. At this time, the cost may be adjusted in consideration of the width information of the link. For example, a narrower link is less likely to pass because it has a higher possibility of contact with a passerby. For this reason, a higher cost is added. On the other hand, when the number of commercial facilities / link length is not equal to or greater than a certain value (step S705: No), the processing according to this flowchart is terminated without multiplying a predetermined coefficient as a normal link.
[0092]
As described above, the route search unit 309 calculates the cost of the link based on information such as the number of facilities around the link and the genre. For this reason, the navigation apparatus 300 can present the route according to the actual traffic situation to the user and perform route guidance.
[0093]
FIG. 8 is a diagram illustrating an example of a route searched by the route search unit. In FIG. 8, the route from the starting point indicated by the triangular flag S to the destination point G indicated by the square flag includes a route A passing through the link L1 and a route B passing through the link L2. When a route is searched by general cost calculation, if other conditions are the same, the route A having a shorter distance is presented to the user as the optimum route.
[0094]
On the other hand, the route search unit 309 adds the number and genre of facilities around the links L1 and L2 to the cost calculation element. Thereby, in the navigation apparatus 300, the route B passing through the link L2 in which the number of surrounding facilities is smaller than that of the link L1 is presented to the user as the optimum route. This is because the route B has a longer distance than the route A, but since the number of surrounding facilities is small, the time required to pass is expected to be short.
[0095]
As described above, according to the navigation device of the present embodiment, in addition to a general cost calculation element, the number of facilities existing around the link is used as a cost calculation element, so that the traffic situation of the link The route to the destination can be searched with more accurate prediction.
[0096]
In addition, by using the facility information included in the map information, the actual situation of the road can be predicted more realistically by adjusting the cost according to the type of facility and business hours provided around the link. In addition, if there is information on matters that affect the degree of attracting customers about facilities around the link, the cost of the link can be calculated in consideration of the matters, and the optimum route can be presented to the user.
[0097]
The route search method described in this embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program is recorded on a computer-readable recording medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. The program may be a transmission medium that can be distributed via a network such as the Internet.

Claims (8)

Facility number information acquisition means for acquiring information related to the number of facilities around the link from address information around the link;
An evaluation unit that evaluates each of the links based on information about the number of facilities acquired by the facility number information acquisition unit;
Search means for selecting a link highly evaluated by the evaluation means and searching for a route to the destination point;
A route search apparatus comprising: The facility number information acquisition means acquires information on the number of facilities per unit length of the link,
The route search apparatus according to claim 1, wherein the evaluation unit gives a high evaluation to a link having a small number of facilities per unit length. Comprising customer acquisition information acquisition means for acquiring information related to the ability to attract customers of the facilities around the link;
The route search apparatus according to claim 1, wherein the evaluation unit gives a low evaluation to a link where a facility having a high ability to attract customers is located in the vicinity. Genre information acquisition means for acquiring information related to the genre of facilities around the link;
The customer information acquisition means acquires information on the ability to attract customers for each genre of facility,
The route evaluation apparatus according to claim 1, wherein the evaluation unit gives a low evaluation to a link where a facility of a genre having a high ability to attract customers is located in the vicinity. The customer information acquisition means acquires information on the ability to attract customers by time of the facility,
The route search apparatus according to claim 1, wherein the evaluation unit gives a low evaluation to a link in the vicinity of a facility in a time zone in which the ability to attract customers is high. A route search method in a route search device,
  A facility number information acquisition step of acquiring information related to the number of facilities around the link from address information around the link;
  An evaluation step for evaluating each of the links based on information on the number of facilities acquired by the facility number information acquisition step;
  A search step of searching for a route to a destination point by selecting a link having a high evaluation by the evaluation step;
  A route search method comprising: A route search program causing a computer to execute the route search method according to claim 6. A computer-readable recording medium on which the route search program according to claim 7 is recorded.

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