JP4252410B2 - Navigation device and alternative route generation notification method - Google Patents

Description

  The present invention relates to a navigation device that performs route guidance for a user.

  In a navigation device mounted on an automobile, as a technique for performing route guidance for a user, a guidance route is conventionally set between a destination received from a user and set as a current position on a map. A technique for guiding traveling to a destination along a guidance route by displaying an image representing the is widely used.

  In addition, as a technology related to a navigation device that performs such route guidance, during route guidance according to the guidance route, a search is made as to whether there is a suitable alternative route than the current guidance route. If there is a suitable alternative route, the alternative route is presented to the user, the selection of whether to set the alternative route as a new guidance route is accepted, and the selection of setting is accepted, A technique for setting an alternative route as a new guidance route and performing subsequent route guidance is known (for example, Patent Document 1).

Further, as a technique for presenting such a guide route and an alternative route that is an alternative to the guide route, a technology for displaying an image that represents both the guide route and the alternative route on a map is known. (For example, Patent Document 2).
JP 2003-90732 A JP 2001-304890 A

Now, especially when the user is traveling, the notification of the occurrence of the alternative route as described above to the user is necessary to know whether or not to adopt the alternative route as the guide route. It is preferable to perform the information about so that the user can intuitively grasp the information.
However, according to the technology that presents the alternative route by displaying an image showing both the guide route and the alternative route on the map, the roads that form each route on the map can be confirmed in detail, The display is likely to be complicated, and it may be difficult for the user to intuitively grasp information for evaluating an alternative route.

  In particular, in a simple display type navigation device that is provided with only a relatively small display device known as arrow navigation and displays an arrow indicating the traveling direction of the vehicle, it replaces the guide route on the map. It is difficult to display an image together with a route on a small display device while ensuring sufficient visibility for the user.

  Therefore, an object of the present invention is to provide notification of an alternative route that is an alternative to a guide route so that the user can intuitively grasp information necessary for evaluating the alternative route.

  In order to achieve the above object, the present invention provides a route that is estimated to be more suitable than the guidance route from the current position to the destination for a navigation device that guides traveling along the guidance route set up to the destination. An alternative route search means for searching for an alternative route, and when the alternative route is searched, when the alternative route is traveled to one of a plurality of magnitude relations including at least predetermined large and small Corresponding to the travel distance relationship classification means for classifying the magnitude relationship between the travel distance and the travel distance when traveling on the guidance route, and the classification classified by the travel distance relationship classification means when the alternative route is searched It is provided with an alternative route notification means for displaying an image representing a corresponding magnitude relation by bending a figure representing a single route prepared in advance.

  According to such a navigation device, when an alternative route is searched for, the occurrence of the alternative route is notified by an image representing the magnitude relationship between the guidance route and the alternative route by bending a figure representing a single route. To do. Therefore, the user can intuitively understand the magnitude relationship between the travel distance when traveling on the alternative route and the travel distance when traveling on the guidance route, and the new guidance route of the alternative route is more intuitive than the displayed image. The right or wrong of adoption can be determined. In addition, the image displayed for the notification of the occurrence of the alternative route in this way is a very simple one containing only a graphic representing a single route representing the alternative route as a graphic representing the route. Also in the apparatus, it is possible to notify the occurrence of an alternative route while maintaining good visibility.

  Here, such a navigation device is further provided with a traffic information receiving device that receives traffic information indicating a traffic event that has occurred, and in the alternative route search means, the traffic information received by the traffic information receiving device is In consideration of the traffic event indicated, the route that is estimated to be better than the guidance route from the current position to the destination is searched, and the traffic indicated by the traffic information received by the traffic information receiving device in the alternative route notification means Among the events, a traffic event mark indicating the type of traffic event on the guided route as a traffic event on the guided route, which is a traffic event occurring in the section on the destination side from the current position on the guided route. May be displayed.

  By doing so, it is possible to notify the user of the occurrence of the alternative route together with the notification of the traffic event occurring on the guidance route. Here, the traffic event occurring on the guidance route is not likely to be the optimum route, and it is highly likely that the alternative route has been searched for as a more suitable route. In consideration of such causes, it is possible to determine whether or not to adopt a new guidance route as an alternative route.

  In addition, when the traffic event mark is displayed as described above, when there are a plurality of traffic events on the guide route, the traffic event mark is generated for each traffic event on the guide route. It is preferable to display sequentially according to the order of the points on the guide route.

  In this way, even when using a small display device without requiring a large display area, the occurrence of a plurality of traffic events on the guidance route can be visually confirmed in the order of the occurrence points on the guidance route. Possible, it can be presented to the user.

  As described above, according to the present invention, an alternative route that is an alternative to a guide route can be notified so that the user can intuitively grasp information necessary for evaluating the alternative route.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a configuration of a navigation device according to the present embodiment.
As shown in the figure, the navigation device includes a control device 1, a recording medium drive 2 for accessing a recording medium 21 such as a DVD-ROM or hard disk storing map data, a GPS receiver 3, an angular acceleration sensor, or a vehicle speed sensor. A travel state sensor 4 that detects the travel state of the vehicle, a traffic information receiver 5, a remote controller 6 (remote controller) that receives input from the user, and a display device 7 are provided. Here, the traffic information receiver 5 is a receiver that receives real-time traffic information broadcast from broadcasting facilities. In addition, as a system for transmitting and receiving traffic information between a broadcasting facility and an on-vehicle receiving device in this way, real-time road traffic information is provided about every 5 minutes via radio wave beacons, optical beacons, FM multiplex broadcasting, etc. in Japan. VICS (Vehicle Information and Communication System) to be sent and received, RDS (Radio Data System) that multiplexes and broadcasts various information such as information on broadcast programs and traffic information to audio broadcasting, and popular in North America In addition, various types of information such as information related to broadcast programs and traffic information are multiplexed and broadcast on an audio broadcast (Radio Broadcast Data System).

  The control device 1 includes a map data buffer 101, a map data read processing unit 102, a current state calculation unit 103, a route search unit 104, a navigation image generation unit 105, a traffic information decoder 106, a memory 107, a main control unit 108, a GUI. A control unit 109 is provided. Here, a dotted line 121 inside the control device 1 in FIG. 1 indicates an access path of each part to map data stored in the map data buffer 101, and a thick line 122 indicates a path of control information between each part and each part of various data. The thin line connected to the GUI control unit 109 indicates the route of operation information and image information input / output with the user using the remote controller 6 or the display device 7.

  However, the control device 1 described above may be a CPU circuit having a general configuration including peripheral devices such as a microprocessor, a memory, and other graphic processors and geometric processors in terms of hardware. In this case, each unit of the control device 1 described above may be realized as a process embodied by a microprocessor executing a program prepared in advance. In this case, such a program may be provided to the control device 1 via the recording medium 21 or an appropriate communication path.

Next, the structure of the map data stored in the recording medium 21 is shown.
Here, the map data is managed in units called leaflets for each predetermined geographical area, and each leaf is composed of a plurality of levels according to the degree of detail of the map. Each level map of each leaf consists of one or more units, and each unit corresponds to the geographical area of the leaf to which it belongs or a divided area, and maps the corresponding area. , Expressed at the level to which it belongs.

As shown in FIG. 2, the map data includes management data that describes the relationship between each unit and the leaf, corresponding area, and level, basic map data that represents the map, route data, and a traffic information conversion table. Consists of.
Here, the basic map data includes the unit data for each unit described above, and unit management data describing the relationship between each unit data and the leaf, corresponding area, and level. Each unit data includes a road unit representing a road network in the unit and a drawing unit for defining a display map in the unit.

The road unit has a node list, a link table, and connection data describing connection and correspondence of nodes and links with other units.
Here, in the road unit, the road is expressed as a set of links that are straight lines, and the end point of each link is a node. Such a node is always provided at a connection point of a road such as an intersection, and is always provided at a boundary between adjacent units. In addition, each link has a direction, and if the road is one-way between two adjacent nodes via the link, only one link in the direction of traffic is provided. In principle, two links in opposite directions are provided.

  The node list includes a node record for each node. Each node record includes a node number, a node coordinate, a node attribute indicating whether the node is a node corresponding to an intersection or an expressway entrance, and the like. A connection link number list, which is a list of link numbers of links connected to the node, and an adjacent node number list, which is a list of node numbers of nodes adjacent to the node via the link, are described.

  Next, the link table includes a link record for each link, and each link record includes a link number, a starting node number indicating the node number of the node that is the starting point of the link, and a node number of the node that is the ending point of the link. End node number to be shown, road attributes representing various information about the section of the road corresponding to the link, link distance, link direction, link cost that is the cost for route search given to the link, route number of the route to which the link belongs Etc. are described. Here, as the road attribute, a road type indicating a type such as a toll road of a road to which the link belongs, a national road, a prefectural road, a road width of the road section corresponding to the link, the number of lanes, and the like are described.

Next, the drawing unit defines display data that schematically represents the road network.
The route data included in the map data has a route record provided for each road, and each route record includes a route number that is an identifier of the road, an expressway of each road, a national road, a prefectural road, etc. The route type and the route name of each road are described.
The traffic information conversion table is a table for coordinate conversion that describes the correspondence between the coordinate system used in the traffic information received by the traffic information receiver 5 and the coordinate system used in the basic map data.
Next, data stored in the memory 107 of the control device 1 in FIG. 1 will be described.
As shown in FIG. 3, the memory 107 stores current state information 301, destination data 302, guidance route data 303, alternative route data 304, and traffic information records 305.
The current state information 301 includes current position data 3011, current traveling direction data 3012, and traveling link data 3013. The current position data 3011 is data representing the current position coordinates of the vehicle. The traveling link data 3013 is data indicating the link number of the currently traveling link. The destination data 302 represents the coordinates of the destination on the link.

  The guide route data 303 is data representing the guide route, and includes a route link list 3031 describing the link number of the link through which the guide route passes and the cost of the link in order of passing, and the node number of the node through which the guide route passes. A route node list 3032 described in the order of passage.

  Further, the alternative route data 304 is data representing an alternative route that is a candidate route for the guide route, and, like the guide route data 303, the link number of the link through which the alternative route passes and the cost of the link in order of the route. The described alternative route link list 3041 and the alternative route node list 3042 in which the node numbers of the nodes through which the alternative route passes are described in the order of passage.

  The traffic information record 305 is provided corresponding to the traffic information received by the traffic information receiver 5. Each traffic information record 305 includes a reception time when the traffic information is received and the traffic information represents the information. Location information that indicates the location or road section, event type that describes the type of event such as traffic regulation or traffic jam or travel time required by the traffic information, and details of the event such as the degree of traffic jam or travel time Is stored.

Now, referring back to FIG. 1, in such a configuration, the map data read processing unit 102 reads the required range of map data from the recording medium 21 via the recording medium drive 2 under the control of the main control unit 108, and the map data Store in the buffer 101.
Further, the current state calculation unit 103 repeatedly performs the following processing.
That is, the current state calculation unit 103 matches the current position estimated from the output of the traveling state sensor 4 or the GPS receiver 3 with the map around the current position previously determined read from the map data buffer 101. Processing, etc., the most probable link coordinates as the current position, the most probable link direction as the current travel direction, and the most probable link as the current travel link, the current position coordinates and the current travel direction, respectively. The link is determined as the running link, and is set in the current position data 3011, the current running direction data 3012, and the running link data 3013 in the memory 107.

  The traffic information decoder 106 decodes the traffic information received by the traffic information receiver 5 with reference to the traffic information conversion table of the map data, and stores it in the memory 107 as a traffic information record 305. In addition, the traffic information decoder 106 deletes the traffic information record 305 having the same type and the same position information as the traffic information received by the traffic information receiver 5, or the reception time is determined from the current time and the current position. A process of deleting the traffic information record 305 indicating that the traffic information is no longer valid is also performed.

Further, the main control unit 108 receives a destination setting from the user via the remote controller 6 and the GUI control unit 109 in response to a user destination setting request, and sets this in the destination data 302.
Then, the route search unit 104 is searched for a guidance route to the destination indicated by the destination data 302. The route search unit 104 reads road data of road units in the necessary geographical area from the map data buffer 101 and travels from the current position coordinates indicated by the current position data 3011 in the memory 107 to the destination coordinates indicated by the destination data 302. The minimum cost route that first follows the link indicated by the medium link data 3013 is calculated as a guide route based on a predetermined cost model using the link cost of the link record and the traffic information indicated by the traffic information record 305, and is calculated. The route data of the guide route is stored in the route link list 3031 and the route node list 3032 of the guide route data 303, respectively. That is, for example, when a cost model with travel time as one of the costs is used as the cost model, the travel time required for the link is included in the link cost of the link record. Then, the travel time required for each link is corrected according to the traffic information in the traffic information record 305, and the cost related to the travel time of the route is obtained. Here, for the correction of the required travel time of the link according to the traffic information, for example, for the link where the traffic congestion has occurred, the link time is required for the travel time according to the degree of the traffic congestion indicated by the traffic information and the length of the link. This is done by correcting the travel time.

Further, the main control unit 108 repeats the process of displaying various information on the display screen of the display device 7 as shown in FIG.
That is, the main control unit draws the destination direction 401 viewed from the current position with reference to the current position data 3011 and the destination data 302. Further, with reference to the current position data 3011, the destination data 302, and the guidance route data 304, the travel distance 402 from the current position to the destination when traveling according to the guidance route is displayed. In addition, referring to the current position data 3011 and the destination data 302, when traveling according to the guidance route, the intersection that will change the traveling direction in the form of the next right or left turn and the traveling direction change at the intersection The direction and the distance to the intersection are obtained, and the obtained distance 403 and the traveling direction change direction 404 are drawn. In addition, the main control unit 108 also draws the current time 405 and the reception state 406 of the GPS receiver 3 on the display screen.

  Also. The main control unit 108 monitors the approach within a predetermined distance of the current position to the intersection that changes the traveling direction, such as a right or left turn, calculated as described above, and the approach within the predetermined distance to such an intersection is detected. If detected, a current position mark 4072 representing the current position on the road image 4071 representing the road network around the current position based on the road unit or drawing unit of the map data, and the current direction along the guide route on the traveling direction side A navigation image 407 representing an arrow graphic 4073 indicating a course change direction at each course change point around the position is drawn on the display screen. Here, the navigation image 407 may be a two-dimensional representation of a road network or a runway as shown in FIG. 4a, or a three-dimensional representation of a road network or a runway as shown in FIG. 4b. It may be.

Then, after displaying the navigation image 407 in this manner, the main control unit deletes the navigation image 407 if all the route change points indicated by the arrow graphic 4073 indicating the route change direction are passed.
Further, during the route guidance as described above, the main control unit 108 determines that the distance between the current position coordinates indicated by the current position data 3011 and the destination coordinates indicated by the destination data 302 is a predetermined distance (for example, several tens of meters) or less. If the distance is less than the predetermined distance, it is assumed that the vehicle has arrived at the destination, the guidance route data 303 and the destination data 302 are cleared, and the route guidance is terminated.

Then, the main control unit 108 performs the following alternative route search process during route guidance according to the above guidance route.
FIG. 5 shows the procedure of the alternative route search process.
However, in the following description, the application to the case where only the travel time is used as the cost will be described as an example of the cost model for the route search.
As shown in the figure, in this process, first, the guide route data 303 and the current state information 301 are referred to, and the cost of the guide route from the current position to the destination is determined as the link cost of the route link list 3031 and the traffic information record. Based on 305, the current cost is calculated (step 502). Here, the current cost changes dynamically according to the traffic situation indicated by the traffic information received by the traffic information receiver 5 in addition to the change with the movement of the current position.

  Next, when there is a traffic information record 305 that causes an increase in the cost of the guidance route from the current position to the destination, the main control unit 108 bypasses the contents of the existing traffic information record 305. Extracted as cause information (step 504). In other words, for example, when a model with travel time as one of the costs is used as a cost model, there is a traffic jam at a point on the guidance route, and this traffic jam does not cause a current traffic cost If the number is increased, the content of the traffic information record 305 representing the occurrence of the traffic jam is extracted as detour cause information.

  Next, the route search unit 104 causes the route search unit 104 to search for an alternative route based on the map data and the traffic information record 305 from the current position to the destination (step 506). The cost of the alternative route is stored, and the alternative route cost is obtained by referring to the alternative route data 304 and the traffic information record 305 (step 508).

  Then, the alternative cost and the current cost are compared (step 510), and if the current cost is equal to or lower than the alternative cost, the process directly returns to step 502. On the other hand, if the alternative cost is smaller than the current cost, the travel distance and the travel time from the current position to the destination between the alternative route and the guide route are obtained as comparison information (step 512).

Then, an alternative route selection process is executed (step 518). When the alternative route selection process is completed, the process returns to step 502.
Here, the procedure of the alternative route selection process in step 518 is shown in FIG.
As shown in the figure, in the alternative route selection process, first, a symbol figure 421 determined in advance for the comparison information obtained in the alternative route search process is displayed on the display screen as shown in FIG. 4C (step 602). However, if the navigation image 407 is currently being displayed, that is, if the guidance for changing the direction of travel is being provided, the display is started after the guidance is completed and the navigation image 407 is deleted.
Here, the symbol graphic 421 is predetermined for the comparison information as shown in FIG.

  In FIG. 7, a1 is a symbol graphic 421 displayed when the comparison information indicates that the travel distance of the alternative route is greater than that of the guide route and the travel time of the alternative route is shorter than the travel time of the guide route. is there. Further, a2 is a symbol graphic 421 displayed when the comparison information indicates that the travel distance of the alternative route is smaller than that of the guidance route and the travel time of the alternative route is shorter than the travel time of the guidance route.

  As shown in the drawing, each symbol figure 421 has a pattern in which the increase / decrease of the travel distance with respect to the guidance route of the alternative route can be grasped at a glance by regarding the line with an arrow as the alternative route. That is, a1 is a figure formed by a circle indicating a branch point and a merge point between the guidance route and the alternative route, and a line with an arrow having a shape that bypasses and passes between the two circles. Is a figure formed by a circle indicating a branch point and a merge point between the guide route and the alternative route, and a line with an arrow having a shape that passes between the two circles at the shortest distance. In addition, as described above, here, the case where a model with only travel time as a cost is set as the cost model for route search is described as an example, so the travel time of the alternative route is always shortened with respect to the guidance route. Will do.

  Returning to FIG. 6, if the symbol graphic 421 is displayed, next, as shown in FIG. 4 c, the travel time and travel distance 422 of the guide route indicated by the comparison information, the travel time and travel distance 423 of the alternative route, and so on. And an OK button 424 and a cancel button 425 are set on the display screen (step 604).

Then, detour cause information display processing is activated (step 606). Details of the detour cause information display processing will be described later.
Next, the main control unit 108 sets a timer having a predetermined timeout time (for example, 10 seconds) (step 608), whether the operation is a cancel button 425 (step 610) or an OK button 424 ( Step 612) Waits for a timer timeout (step 614) to occur.

If the cancel button 425 is operated, the detour information display process is terminated, the display screen is restored to the display before the symbol graphic 421 is displayed (step 618), and the process is terminated.
On the other hand, if the timeout or the operation of the OK button 424 occurs, the substitute route data 304 is replaced with the guide route data 303 (step 616), the detour information display process is terminated, and the display screen display is changed to the symbol. The display returns to the display before the graphic 421 is displayed (step 618), and the process ends.

As a result, the alternative route is set as a new guidance route, and thereafter, the route guidance by the navigation image 407 of the new guidance route is performed.
Now, the detour cause information display process described above will be described.
In the detour cause information display process, the detour cause information is first referenced, and the route along the guide route from the current position of the point on the guide route where the traffic event indicated by the detour cause information occurs from the position information of the detour cause information Calculate the distance. Then, as shown in FIG. 4c, the calculated journey distance 427 is drawn on the display screen together with the traffic information mark 426 corresponding to the traffic event type indicated by the event type of the detour cause information. FIG. 7b shows an example of the traffic event mark displayed in this manner. In the figure, b1 is a traffic event mark representing a traffic jam of 1 to 5 km, b2 is a traffic event mark representing a traffic jam of 5 km to 10 km, b3 is A traffic event mark representing a traffic jam of 10 to 20 km, b4 is a traffic event mark representing construction work, and b5 is a traffic event mark representing a traffic accident.

  Here, the traffic event mark 426 and the journey distance 427 are drawn at a predetermined position according to the type of the drawn symbol figure 421. That is, when the symbol figure 421 is drawn when the alternative route of FIG. 7a1 has a longer travel distance than the guidance route, as shown in FIG. 4c, between the two circles representing the branch point on the line with an arrow. A traffic event mark 426 and a distance 427 are drawn. In addition, when the symbol graphic 421 is drawn when the travel distance of the alternative route 7a2 is smaller than the guidance route, as shown in FIG. An event mark 426 and a journey distance 427 are drawn.

Further, in the detour cause information display process, if a plurality of detour cause information is extracted, a set of the traffic event mark 426 and the detour distance 427 for each detour cause information in order from the shortest calculated distance. Are displayed cyclically at regular intervals.
That is, for example, in the extracted detour cause information, there is a traffic jam of 4 km at a distance of 3.4 km on the guidance route, and construction is occurring at a distance of 7.2 km on the guidance route. If there is a traffic jam of 8 km 15 km away, the traffic event mark 426 and the distance 427 are displayed sequentially for a certain period (for example, 0.8) in the order of FIG. 8a, b, c, a, b, Switch every second).

  In the detour cause information display process, as shown in FIG. 8d, the selected traffic event mark is displayed in accordance with a predetermined operation, for example, selection of the displayed traffic event mark 426 with the cursor or a predetermined operation of the remote controller. The content 801 of the corresponding detour cause information is displayed in the form of a balloon from the traffic event mark.

The embodiment of the present invention has been described above.
In addition, although this embodiment demonstrated taking the example to application to the simple navigation apparatus which guides the advancing direction, such as a left-right turn along a guidance route with an arrow, the present position and guidance are always on a map during route guidance. The technique of presenting an alternative route according to the present embodiment can be similarly applied to a navigation device that expresses a route and performs route guidance.

It is a block diagram which shows the structure of the navigation apparatus which concerns on embodiment of this invention. It is a figure which shows the map data with which the navigation apparatus which concerns on embodiment of this invention is provided. It is a figure which shows the data which the navigation apparatus concerning embodiment of this invention stores in memory. It is a figure which shows the example of a display screen of the navigation apparatus which concerns on embodiment of this invention. It is a flowchart which shows the procedure of the alternative route search process which concerns on embodiment of this invention. It is a flowchart which shows the procedure of the alternative route selection process which concerns on embodiment of this invention. It is a figure which shows the symbol figure and traffic event mark which are used in the navigation apparatus which concerns on embodiment of this invention. It is a figure which shows the example of a display screen of the navigation apparatus which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Control apparatus, 2 ... Recording medium drive, 3 ... GPS receiver, 4 ... Running state sensor, 5 ... Traffic information receiver, 6 ... Remote control, 7 ... Display apparatus, 21 ... Recording medium, 101 ... Map data buffer, DESCRIPTION OF SYMBOLS 102 ... Map data reading process part, 103 ... Current state calculation part, 104 ... Route search part, 105 ... Navigation image generation part, 106 ... Traffic information decoder, 107 ... Memory, 108 ... Main control part, 109 ... GUI control part.

Claims (4)

A navigation device that guides driving along a guidance route set up to a destination,
An alternative route search means for searching for an alternative route that is estimated to be more preferable than the guidance route from the current position to the destination;
When the alternative route is searched, the travel distance when traveling on the alternative route and the travel when traveling on the guidance route in any of a plurality of magnitude relations including at least predetermined large and small Mileage relationship classification means for classifying the magnitude relationship with the distance;
When the alternative route is searched, a graphic representing a single route prepared in advance corresponding to the classification classified by the mileage relationship classification means , and corresponding to the magnitude relationship corresponding to the presence or absence of bending of the graphic An alternative route notification means for displaying an image including a graphic representing a section. The navigation device according to claim 1,
A traffic information receiving device for receiving traffic information indicating a traffic event that has occurred,
The alternative route search means searches for a route presumed to be more preferable than the guidance route from the current position to the destination in consideration of the traffic event indicated by the traffic information received by the traffic information receiving device,
The alternative route notification means is on a guidance route that is a traffic event occurring in a section on the destination side from at least the current position on the guidance route among the traffic events indicated by the traffic information received by the traffic information receiving device. A navigation device characterized by displaying a traffic event mark representing a traffic event type as a traffic event on a guided route. The navigation device according to claim 2,
When there are a plurality of traffic events on the guidance route, the alternative route notification means displays the traffic event mark for each traffic event on the guidance route in the order on the guidance route of the point where the traffic event occurs. The navigation device is characterized by sequentially displaying according to the above. In the navigation device that guides the traveling along the guide route set up to the destination, an alternative route generation notification method for notifying the occurrence of an alternative route that substitutes for the guide route,
Searching for an alternative route that is presumed to be better than the guidance route from the current position to the destination;
When the alternative route is searched, the travel distance when traveling on the alternative route and the travel when traveling on the guidance route in any of a plurality of magnitude relations including at least predetermined large and small Classifying the magnitude relationship with the distance;
When the alternative route is searched, a single prepared in advance corresponding to the classified classification of the magnitude relationship between the travel distance when traveling on the alternative route and the travel distance when traveling on the guidance route, An alternative path generation notification method , comprising: a step of displaying an image including a figure representing a path of the figure and a figure representing a corresponding magnitude relation according to the presence or absence of bending of the figure .

Images