JP6140592B2 - Cyclic route search apparatus and method, computer program for searching a circular route, and recording medium recording the computer program - Google Patents

Description

  The present invention relates to an apparatus and a method for searching for a route that comprehensively circulates links in a predetermined area.

In general, map data used in a navigation device or the like is information such as position information obtained by actually traveling on a road to be surveyed by a vehicle, or a captured image of the front and rear of a vehicle obtained by a vehicle-mounted video camera or the like. It is created based on etc. Various developments have been made on the patrol route for such field surveys.
For example, in Patent Document 1, when there is an identical section that passes a plurality of times in a cyclic route, a complicated route display is displayed by shifting and displaying a plurality of route lines indicating route guidance. A technique for making it easier to see is disclosed.
See also Patent Document 2 or 3 disclosing the prior art related to the present invention.

JP2011-180101A JP 2006-113460 A JP 2001-194175 A

It would be ideal if the vehicle could be run along the patrol route that was once drawn to conduct a field survey (hereinafter also referred to as “running current”), but in reality, it would run along the patrol route due to construction or traffic jams. There are many cases where this is not possible. And it is necessary to drive | work separately about the road which was not able to drive | work. Conventionally, in preparation for such a case, a road that has already traveled and a road that has not traveled are separately checked on the map paper while performing the current state of travel. However, it is dangerous for the driver to check while the vehicle is traveling, and it is difficult to check in real time. On the other hand, if you carry the personnel to perform the check, you can avoid danger but increase labor costs.
Accordingly, the present inventors have conducted intensive studies to implement more efficient running conditions while ensuring safety. As a result, based on the map database storing the survey target link for searching the patrol route and the vehicle travel history, the travel target link is deleted from the map database, the map database is updated, The present inventors have conceived that the above problem can be solved by searching for a new route using the updated map database.

The present invention has been made in view of the above-mentioned problems, and the first aspect is defined as follows. That is,
In a traveling route search device for searching a traveling route for traveling a target link satisfying a predetermined condition by a vehicle,
A map data for searching the patrol route, a first map database storing map data including information on the target link in a first area;
A travel history database that accumulates travel history traveled by the vehicle;
Based on the travel history, a traveled link identifying unit that identifies a traveled link among the target links in the first map database;
A map database update unit for updating the first map database by deleting the identified traveled link from the target link in the first map database;
With reference to the updated first map database, a traveling route search unit for searching for the traveling route;
A traveling route search device comprising:

  According to the traveling route searching apparatus of the first aspect defined as described above, the traveled link specified based on the traveling history of the vehicle is deleted from the traveling target link in the predetermined area stored in the map database. Thus, the map database is updated, and the updated map database is referenced to search for a patrol route that can travel around the untraveled link. By specifying the traveled link based on the travel history in this way, it is possible to provide a map database in which the traveled link and the non-traveled link are distinguished from each other without requiring successive checks on the map paper. Further, it is possible to provide a route that can travel around the untraveled link based on the updated map database. Since the update of the map database and the reroute search for the untraveled link patrol are automatically performed, the driver can concentrate on driving and secure safety.

Here, the cyclic route is a route for more efficiently circulating the target link existing in the first area. As such a cyclic route, for example, the target link in the area is written in one stroke. A route traveling in a manner, a route in which the number of times traveling on the same target link while traveling on more target links in the area is suppressed as much as possible, and the like.
A link is a component of road network data and generally refers to data generated corresponding to a road connecting nodes between nodes corresponding to a road intersection or the like. The target link is a link that is a target of a cyclic route among links included in a normal map database, and is selected based on, for example, a link attribute. Examples of such link attributes include link width, link type, number of lanes, route number, and the like. Specifically, a link whose link width is equal to or greater than a predetermined threshold, a link whose link type is a highway, a highway, a link whose number of lanes is equal to or greater than a predetermined threshold, and the like are selected as target links. The target link may be selected manually by an operator in addition to being selected based on the link attribute.

  A traveled link is a link traveled by a vehicle. Preferably, the target link that has completely run from one end point to the other end point of the target link can be identified as the traveled link (third aspect). According to such an apparatus, information over the entire target link can be acquired, and a more detailed map database can be created. As another example of the traveled link, a link that travels at a predetermined rate or more (for example, 50% or more) in one target link may be used as the traveled link. As another example, when a part of one target link is traveled, information indicating that the traveled part has been traveled may be given to the target link to be a traveled link. . For example, based on the coordinates where the travel history deviates from the target link, when the vehicle has already traveled to the departure point, or when the steering wheel operation is performed against the link shape of the target link, the operation is performed based on the coordinates at which the operation was performed. It can be assumed that the vehicle has already traveled to the point. In this case, the map database update unit can update the map database by deleting the traveled part in the traveled link.

When the number of non-running links is reduced within a predetermined area, it is not efficient to search for a route that circulates only the non-running links.
Therefore, the second aspect of the present invention is defined as follows. That is,
In the cyclic route search device defined in the first aspect, map data for searching the cyclic route, the map data including information on the target link in a second area adjacent to the first area A second map database for storing
A ratio calculation unit that calculates a ratio of the traveled link to the target link in the first area;
The cyclic route search unit searches for the cyclic route with reference to the updated first map database and the second map database when the calculated ratio is equal to or greater than a predetermined threshold.
According to the cyclic route searching apparatus of the second aspect defined as described above, the ratio of the traveled links in the predetermined area is calculated, and when the ratio is equal to or greater than the predetermined threshold, the area adjacent to the area is included. As a result, the efficiency of the field survey is improved.

The fourth aspect of the present invention is defined as follows. That is,
In a traveling route search method for searching a traveling route for traveling a target link satisfying a predetermined condition by a vehicle,
A first storing step of storing map data for searching the patrol route, the map data including information on the target link in a first area in a first map database;
An accumulating step for accumulating in the travel history database the travel history that the vehicle has traveled;
A traveled link identifying step, wherein the traveled link identifying unit identifies a traveled link among the target links in the first map database based on the travel history;
A map database update unit for updating the first map database by deleting the identified traveled link from the target link in the first map database; and
A traveling route search unit that refers to the updated first map database and searches for the traveling route;
A traveling route search method comprising:
According to the invention of the fourth aspect defined as described above, the same effect as that of the first aspect can be obtained.

The fifth aspect of the present invention is defined as follows. That is,
In the method defined in the fourth aspect, the map data for searching the patrol route, the map data including information on the target link in the second area adjacent to the first area is a second map data. A second storage step of storing in the map database of
A ratio calculating unit that calculates a ratio of the traveled link to the target link in the first area; and
In the cyclic route search step, when the calculated ratio is equal to or greater than a predetermined threshold, the cyclic route is searched with reference to the updated first map database and the second map database.
According to the fifth aspect of the invention thus defined, the same effects as those of the second aspect can be achieved.

The sixth aspect of the present invention is defined as follows. That is,
In the method defined in the fourth or fifth aspect, in the traveled link specifying step, the target link that has completed the travel from one end point to the other end point of the target link is specified as the traveled link.
According to the sixth aspect of the invention thus defined, the same effect as the third aspect can be obtained.

Furthermore, the seventh aspect of the present invention is defined as follows. That is,
A computer program for searching a patrol route for patrol a target link that satisfies a predetermined condition by a vehicle,
Map data for searching the patrol route, the map data including information on the target link in the first area stored in a first map database;
Accumulation means for accumulating a travel history of the vehicle in a travel history database;
Based on the travel history, a traveled link identifying means for identifying a traveled link among the target links in the first map database;
Map database update means for updating the first map database by deleting the identified traveled link from the target link in the first map database;
A roundabout route searching means for searching for the roundabout route with reference to the updated first map database;
As a computer program.
According to the seventh aspect of the invention thus defined, the same effect as the first aspect can be obtained.

The eighth aspect of the present invention is defined as follows. That is,
In the computer program defined in the seventh aspect, the computer is further
A second storage that stores map data for searching for the traveling route, the map data including information on the target link in a second area adjacent to the first area in a second map database. Means,
A ratio calculating means for calculating a ratio of the traveled link to the target link in the first area;
When the calculated ratio is greater than or equal to a predetermined threshold, the cyclic route search means searches for the cyclic route with reference to the updated first map database and the second map database.
According to the invention of the eighth aspect defined as described above, the same effect as that of the second aspect can be obtained.

The ninth aspect of the present invention is defined as follows. That is,
In the computer program stipulated in the seventh or eighth aspect, the traveled link specifying means specifies a target link that has run from one end point to the other end point of the target link as the traveled link.

  A recording medium for recording a computer program defined in any of the seventh to ninth aspects is defined as a tenth aspect.

FIG. 1 is a block diagram showing a configuration of a cyclic route search apparatus 1 according to an embodiment of the present invention. FIG. 2 is a flowchart showing an example of the operation of the traveling route searching apparatus 1 according to the embodiment of the present invention. FIG. 3 shows (A) map data stored in the first map database 3, (B) travel history data stored in the travel history database 5, and (C) updated first map database. 3 is a schematic diagram for explaining map data stored in 3. FIG. FIG. 4 is a block diagram showing a configuration of a cyclic route search apparatus 21 according to another embodiment of the present invention. FIG. 5 is a flowchart showing an example of the operation of the cyclic route search apparatus 21 according to another embodiment of the present invention. FIG. 6 shows (A) map data stored in the first map database 3, (B) travel history data stored in the travel history database 5, and (C) updated first map database 3. It is a schematic diagram for demonstrating the map data stored in 1 and the map data stored in a 2nd map database. FIG. 7 is a block diagram showing the configuration of the mobile terminal device 51 according to the embodiment of the present invention.

A traveling route searching apparatus according to an embodiment of the present invention will be described.
FIG. 1 shows a schematic configuration of the cyclic route search apparatus 1. This will be described below with reference to the schematic diagram shown in FIG.
As shown in FIG. 1, the traveling route searching apparatus 1 includes a first map database 3, a traveling history database 5, a traveled link specifying unit 7, a map database updating unit 9, and a traveling route searching unit 11.

The first map database 3 stores map data for searching for a patrol route and including information related to the target link in the first area (see FIG. 3A). The first map database 3 can be created by applying the above-mentioned criteria to a normal map database. Specifically, it is created by giving a high value cost (for example, cost ∞) to links other than the target link among links in a normal map database. If such a first map database is used, the target link is substantially selected as the target of the cyclic route. In addition, even if data indicating “unrunning” or “running times 0” is input to the target link stored in the first map database 3 by default, good. In FIG. 3A, a target link for which data indicating “not running” is set is indicated by a thick line (L _{11 to} L ₂₂ ).

The traveling history database 5 stores traveling histories that the vehicle has traveled (see FIG. 3B). In the travel history database 5, for example, based on the probe information of the vehicle, the history R _{1 to} R _{10 of} each link traveled by the vehicle is accumulated. The travel histories R _{1 to} R ₁₀ of each link can be represented, for example, as dotted lines in FIG. The history of each link may include travel date and time, travel speed, traveled lane, and the like.
The traveled link specifying unit 7 specifies a traveled link among the target links in the first map database based on the travel history accumulated in the travel history database 5. The method for specifying the traveled link is not particularly limited, but a part of the target link, for example, one that has traveled more than half, can be identified as the traveled link. As another example, for the part that has run from one end point of the target link to the other end point is specified as the above-mentioned traveled link, or even if the target link is not completed It is good also as specifying as having already run partially. Furthermore, the information regarding the travel date and time, the travel speed, and the traveled lane can be used to identify the traveled link. For example, among the accumulated travel histories, a travel history with a travel time between 10:00 and 17:00 can be used, or a travel history with a travel speed of 60 km / h or less can be used.

  The map database update unit 9 updates the first map database by deleting the traveled link specified by the traveled link specifying unit 7 from the target link in the first map database (FIG. 3). (See (C)). As the method of the cancellation, for example, the first map database 3 is rewritten by replacing “unrunning” data preset for the target link in the first map database 3 with “running” data. Can be updated. As another example, the update may be performed on the traveled link by adding the number of times of travel to the preset “number of times of travel” as “number of times of travel 1”. . As shown in FIG. 3C, in the updated map database, only a target link for which “unrunning” data is still set can be represented by a thick line. The map database update unit 9 may update sequentially based on the identified traveled links, or may update at predetermined intervals. Moreover, it is good also as updating at the timing which turned off the engine, the timing which finished drive | working the searched circulation route, etc.

The traveling route search unit 11 searches the traveling route with reference to the first map database 3 (see FIG. 3C) updated by the map database update unit 9. As a method of the search, for example, a route on which a target link for which “unrunning” data is set, or a target link for which data of “number of times of driving” is set can be traveled in a one-stroke manner. Can be explored. Of course, the tour route may include a target link other than the target link that has not traveled, a target link other than the target link that has run 0 times, and a link other than the target link. In this example, a route indicated by a dotted line in FIG. For the link L ₂₀ that remains as an untraveled target link after traveling on the circuit route, a new circuit route may be searched to travel the link L ₂₀ , or the circuit route search device 21 described later may be used. It is also possible to search for a route so that it can be visited together with the target link in the adjacent area.

An example of the operation of the cyclic route search apparatus 1 shown in FIG. 1 will be described with reference to FIG.
First, in step 1, a travel history acquisition unit (not shown) acquires vehicle travel histories R _{1 to} R ₁₀ and stores them in the travel history database 5. An example of the accumulated travel histories R _{1 to} R ₁₀ is shown in FIG.
In step 3, the traveling Linked specifying section 7 refers to the first map database 3, and extracts the target link L _m corresponding to the travel history R _n obtained in step 1. For example, the target link L ₁₁ is extracted as a target link corresponding to the travel history R _1.
In step 5, the traveled link specifying unit 7 determines whether or not the travel history R _n acquired in step 1 has completely traveled between both end points of the target link L _{m in} step 3. If yes in step 5, proceed to step 7. For example, since the extracted travel history R ₁ travels from one end point of the target link L _{11 to} the other end point, the process proceeds to step 7. For example, in FIG. 3B, the travel histories R ₇ and R ₁₀ have not completed the travel between the end points of the corresponding links L ₂₀ and L ₁₇ , respectively.

In step 7, the traveling Linked specifying section 7 specifies the running Linked the target link L _m which is extracted in step 3.
In step 9, the map database update unit 9 rewrites the “unrunning” data set by default to the identified target link L _m to “running” based on the result of step 7, thereby changing the first. The map database 3 is updated. The updated first map database 3 is represented as shown in FIG. 3C, for example.
For travel history _{R n + 1} subsequent to the travel history _{R n,} executes steps 3 9 (step 11, 13).
In step 15, the cyclic route search unit 11 searches for a circular route with reference to the first map database 3 updated by executing step 9. That is, in the updated first map database 3, for example, in FIG. 3C, a dotted line in order to circulate the untraveled target links L ₁₅ , L ₁₇ , L ₁₈ , L ₁₉ , L ₂₀ , and L ₂₂ . Search for a patrol route as shown in.

FIG. 4 shows a traveling route searching apparatus 21 according to another embodiment. 4, the same elements as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is partially omitted.
FIG. 4 shows that when there are few untraveled target links in a predetermined area, a traveling route is searched by combining the untraveled target links in the area and the target links in the area adjacent to the area. This is a traveling route search device 21 capable of That is, the apparatus 21 further includes a second map database 23 and a ratio calculation unit 25 in the apparatus 1 shown in FIG. 1, and includes a cyclic route search unit 27 instead of the cyclic route search unit 11.

The second map database 23 stores map data for searching for a patrol route, and includes map data including information regarding the target link in the second area adjacent to the first area. The second area only needs to be adjacent to the first area, and it is not necessary that the links in both areas are directly connected, and even if the links in both areas overlap. good. The second map database 23 may be updated by the same method as the first map database 3.
The ratio calculation unit 25 refers to the updated first map database 3 and calculates the ratio of the traveled links to all the target links in the first area. As the calculation method, for example, the ratio of the number of links of the traveled link to the number of links of all target links in the first area can be calculated. As another example, the ratio of the total distance of the traveled link to the total distance of all target links in the first area may be calculated.

When the ratio calculated by the ratio calculation unit 25 is equal to or greater than a predetermined threshold, the cyclic route search unit 27 refers to the updated first map database 3 and second map database 23 and searches for a cyclic route. Explore. The search method is not particularly limited, and can be performed in the same manner as the above-described traveling route search unit 11. In particular, the traveling route search unit 27 may preferentially tour the target links (untraveled target links) in the first map database 3 in which the ratio of the identified traveled links is larger. . The predetermined threshold can be set to 80% or more, for example.
It is good also as a cyclic route search system which makes a part of component of the said cyclic route search device 21 executable by a server apparatus. Although the structure which can be performed with the said server apparatus is not specifically limited, For example, it can be set as the map database update part 9, the ratio calculation part 25, and the cyclic route search part 27. By centrally managing the server device, the map database can be updated in a batch based on the traveling histories of different vehicles, and an efficient patrol route can be searched.

An example of the operation of the cyclic route search apparatus 21 shown in FIG. 4 will be described with reference to FIG.
First, in step 21, as in step 1, a travel history acquisition unit (not shown) acquires the travel histories R _{20 to} R ₂₇ of the vehicle and stores them in the travel history database 5. An example of the accumulated travel histories R _{20 to} R ₂₇ is shown in FIG.
In step 23, the traveled link specifying unit 7 refers to the first map database 3 and extracts the target link L _m corresponding to the travel history R _n acquired in step 21. For example, the target link L ₁₇ is extracted as the target link corresponding to the travel history R ₂₀ .
In step 25, the traveling Linked specifying section 7, the target in the link L _m is extracted at step 23, identifying the overlapping portions of the travel history R _n and the traveling Linked. The Specific methods, for example, it compares the coordinates of the travel history R _n of the target link L _m, travel history R _n is the partial travel Linked to the point that deviates from the target link L _m Can do. As another example, based on the probe information of the vehicle, for example, the portion up to the point of performing the steering operation against the link shape of the target link L _m may be traveling Linked. For example, in FIG. 6 (B), the travel history R ₂₀ is overall target link L ₁₇ for overlap over the entire area of the corresponding object link L ₁₇ is specified as the running Linked. On the other hand, since the travel history R ₂₅ partially overlaps with the corresponding target link L ₁₉ , the portion overlapping the travel history R ₂₅ in the target link L ₁₉ is specified as the traveled link.

In step 27, the map database update unit 9 rewrites based on the result of step 25, the data "not running" that has been set to the specified target link L _m to "travel completed", or partly specific For the traveled link, the first map database 3 is updated by reflecting the information indicating “traveled” for the portion.
For travel history _{R n + 1} subsequent to the travel history _{R n,} executes step 23 to step 27 (step 29, 31).
In step 33, the ratio calculation unit 25 calculates the total distance of all the target links in the first map database 3.
In subsequent step 35, the ratio calculation unit 25 calculates the total distance of the portion identified as the traveled link among the target links in the first map database 3.
In step 37, the ratio calculation unit 25 calculates the ratio of the traveled links to all the target links based on the calculation results of steps 33 and 35. As a result of the calculation, when the ratio of the traveled links is 80% or more (step 39: Yes), the process proceeds to step 41.

In step 41, the traveling route search unit 27 refers to the updated first map database 3 and the second map database 23, and determines the untraveled target link and the second area in the first area. Search for a tour route to visit the untraveled link. That is, in the first map database 3 is updated, in order to cycle through non-running portion of the target link L _19, L _20, for example, in FIG. 6 (C), searches for a patrol route as shown by a dotted line.
On the other hand, if No in step 39, the process proceeds to step 43.
In step 43, the traveling route search unit 27 searches the traveling route to visit the untraveled link in the first area with reference to the updated first map database 3.

FIG. 7 shows a mobile terminal device 51 of the embodiment. In FIG. 7, the same elements as those in FIGS. 1 and 4 are denoted by the same reference numerals, and the description thereof is partially omitted.
FIG. 7 shows a mobile terminal device 51 including the device 21 shown in FIG. The mobile terminal device 51 includes a control unit 510, a memory unit 511, an input unit 512, an output unit 513, an interface unit 514, a terminal position specifying unit 515, a probe information acquisition unit 516, a first map database 3, and a second A map database 23, a travel history database 5, a traveled link identification unit 7, a ratio calculation unit 25, a map database update unit 9, and a tour route search unit 27 are provided.

The control unit 510 is a computer device including a CPU, a buffer memory, and other devices, and controls other elements constituting the mobile terminal device 51.
A computer program is stored in the memory unit 511, and the computer program is read into the control unit 510, which is a computer device, and causes it to function. This computer program includes an internal hard disk or internal memory as a storage device of a mobile terminal device, an SD (registered trademark) memory card, a memory stick, a smart media, a compact flash (registered) as a storage medium replaceable with the mobile terminal device. Trademark), DVD, and other general-purpose media.
The input unit 512 is used for inputting a user command, for example. Specifically, it is used for inputting a destination or the like in the above-mentioned cyclic route search. As the input unit 512, a pointing device such as a touch panel that cooperates with the display content of a mouse, a light pen, or a display, or a voice input device such as a keyboard or a microphone can be used.

The output unit 513 includes a display, and other information such as the position of the terminal device specified by the terminal position specifying unit 515 described later, the cyclic route searched by the cyclic route search unit 27, the display of the target link and the non-running link, etc. Is displayed. The output unit 513 can include a voice transmission unit.
The interface unit 514 connects the mobile terminal device 51 to a wireless network or the like.
The terminal location specifying unit 515 specifies the current location information of the terminal device using a GPS device or a gyro device. In addition, the current time can be specified.
The probe information acquisition unit 516 acquires vehicle probe information. The probe information acquisition unit 516 may acquire probe information transmitted from vehicles connected wirelessly via a network, or may be temporarily stored in a memory in the vehicle and obtained directly or via a wire. It is good also as acquiring probe information. The probe information includes at least coordinate information and ID information for specifying the probe car. Such information can be specified if the vehicle has a position detection function such as GPS. Furthermore, time information, speed information, heading information, altitude information, accelerator opening, engine speed, longitudinal acceleration, yaw rate, stop lamp, ABS warning lamp, fuel consumption, remaining power capacity, rudder angle (steering wheel rotation angle information) ), Shift lever information or the like.

  Although the embodiments and examples of the present invention have been described above, two or more of the embodiments (examples) may be combined and implemented. Alternatively, one of these embodiments (examples) may be partially implemented. Furthermore, among these, two or more embodiments (examples) may be partially combined.

  The present invention is not limited to the description of the embodiments and examples of the invention described above. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

1 21 patrol route search device 3 23 map database (map DB)
5 Travel history database (travel history DB)
7 Traveled link identification unit 9 Map database update unit (map DB update unit)
11 27 patrol route search unit 25 ratio calculation unit

Claims (7)

In a traveling route search device for searching a traveling route for traveling a target link satisfying a predetermined condition by a vehicle,
A map data for searching the patrol route, a first map database storing map data including information on the target link in a first area;
A map data for searching the patrol route, a second map database storing map data including information on the target link in a second area adjacent to the first area;
A travel history database that accumulates travel history traveled by the vehicle;
Based on the travel history, a traveled link identifying unit that identifies a traveled link among the target links in the first map database;
A map database update unit for updating the first map database by deleting the identified traveled link from the target link in the first map database;
A ratio calculating unit that calculates a ratio of the traveled link to the target link in the first area;
A patrol route search unit that searches the patrol route with reference to the updated first map database ,
The traveling route search unit, when the calculated ratio is equal to or greater than a predetermined threshold, refers to the updated first map database and the second map database, and searches for the traveling route;
Traveling route search device. The traveled link specifying unit specifies the target link that has completed the run from one end point of the target link to the other end point as the traveled link,
Patrol route searching apparatus according to claim 1. In a traveling route search method for searching a traveling route for traveling a target link satisfying a predetermined condition by a vehicle,
A first storing step of storing map data for searching the patrol route, the map data including information on the target link in a first area in a first map database;
A second storage that stores map data for searching for the traveling route, the map data including information on the target link in a second area adjacent to the first area in a second map database. Steps,
An accumulating step for accumulating in the travel history database the travel history that the vehicle has traveled;
A traveled link identifying step, wherein the traveled link identifying unit identifies a traveled link among the target links in the first map database based on the travel history;
A map database update unit for updating the first map database by deleting the identified traveled link from the target link in the first map database; and
A ratio calculating step of calculating a ratio of the traveled link with respect to the target link in the first area;
A traveling route search unit that refers to the updated first map database and searches for the traveling route ;
In the cyclic route search step, when the calculated ratio is equal to or greater than a predetermined threshold, the cyclic route is searched with reference to the updated first map database and the second map database.
Patrol route search method. In the traveled link specifying step, the target link that has completely run from one end point of the target link to the other end point is specified as the traveled link.
The traveling route search method according to claim 3 . A computer program for searching a patrol route for patrol a target link that satisfies a predetermined condition by a vehicle,
Map data for searching the patrol route, the map data including information on the target link in the first area stored in a first map database;
A second storage that stores map data for searching for the traveling route, the map data including information on the target link in a second area adjacent to the first area in a second map database. Means,
Accumulation means for accumulating a travel history of the vehicle in a travel history database;
Based on the travel history, a traveled link identifying means for identifying a traveled link among the target links in the first map database;
Map database update means for updating the first map database by deleting the identified traveled link from the target link in the first map database;
A ratio calculating means for calculating a ratio of the traveled link to the target link in the first area;
Refer to the updated first map database, function as a tour route search means for searching the tour route ,
The cyclic route search means, when the calculated ratio is equal to or greater than a predetermined threshold, refers to the updated first map database and the second map database, and searches for the cyclic route;
Computer program. The traveled link specifying means specifies the target link that has completed the travel from one end point of the target link to the other end point as the traveled link,
The computer program according to claim 5 . A recording medium for recording the computer program according to claim 5 .

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