JP2006003264A - Route search with passing spot designation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire a continuous route having no interruption at a passing spot, in route search with passing spot designation. <P>SOLUTION: In a route search device, designation of a starting place ST, the passing spot V1 and a destination DST is inputted as spots used for route search. Concerning a passing spot V1 not existing on links L1-L7 and on nodes N1-N6, lead-in points P11, P12 which are alternative spots on route search are set on the links. The route search is executed by dividing into sections, namely, the starting place ST to the passing spot V1 and the passing spot V1 to the destination DST, in this state. In this case, points wherein the route search is succeeded both in an entrance time into the lead-in point and in a retreating time from the lead-in point are used as the lead-in points used for the route search. Thus, the continuous routes R1, R2 wherein movability in the whole route including the passing spot V1 is guaranteed can be acquired. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a route search with designation of a starting point, a destination, and a waypoint.

  Route search technology using electronic map data has become widespread. In the route search, a technique that can specify a waypoint to pass along the way in addition to a departure point and a destination has been proposed (for example, a technique described in Patent Document 1). In general, a first-stage route search is performed with a departure point as a search start point and a transit point as a search end point, and then a second-stage route search with a transit point as a search start point and a destination as a search end point. To obtain a route that passes through the route as a whole. Similarly, when there are multiple waypoints, for each section divided by waypoints, a route search is performed with the route start point as the search start point and the stop point as the search end point. A method for obtaining a route is taken.

Japanese Patent Laid-Open No. 10-170294

  However, in the prior art, there is a possibility that the continuity of the route passing through the transit point cannot be ensured. For example, consider a case where a route search is performed for the road shown in FIG. The roads are represented by nodes N1 to N6 and links L1 to L7, respectively. In the link L4, traffic restriction by one-way traffic Tr1 is set.

  In this state, let us consider a case where a node N1 is set as a departure place ST and a node N5 is set as a destination DST, and a route passing through the waypoint V1 is searched. Since the waypoint V1 is not a point on a node or link, at the time of route search, it is necessary to set an alternative point on the route search called a “pull-in point” on a link in the vicinity of the waypoint V1. In the illustrated example, a pull-in point P11 on the link L4 and a pull-in point P12 on the link L5 are set. The service point P11 is closer to the waypoint V1 than the service point P12.

  In the route search from the departure point ST to the waypoint V1, since the one-way Tr1 is set to the link L4, the route R1 having the pull-in point P12 as the search end point is obtained. In the route search from the waypoint V1 to the destination DST, a route R3 having a search start point as the nearest pull-in point P11 of the waypoint V1 is obtained. As a result, the entire route passing through the waypoint V1 becomes routes R1 and R3, and the route between them is interrupted. If there is no route R4 connecting the pulling points P12 and P11, it may be impossible to move along the obtained route.

  An object of the present invention is to solve such a problem and to realize a search for a route that can be actually moved in a route search involving designation of a waypoint.

  The route search apparatus of the present invention performs a route search with reference to road network data including links, nodes, and traffic regulation information associated with the links or nodes. The traffic restriction information refers to information that restricts the direction of travel in a link or node, such as one-way traffic, right turn or left turn prohibition. The route search apparatus inputs a starting point, a destination, and at least one waypoint for route search. In addition, for a transit point that is not on a link or node, a plurality of pull-in points that are substituted for the transit point are set on any link or node for route search. Then, based on the road network data, a search is made for a route passing through the departure point, one of the pull-in points, and the destination. In this route search, for each of the transit points, there are drawn points where both an approach search for searching for a route with a pull-in point as a search end point and an exit search for searching for a route with the pull-in point as a search start point are established. Run under conditions of use. By doing so, the continuity of the route before and after the waypoint is ensured, and it is possible to obtain a route that can actually move.

  A pull-in point that satisfies the above-described conditions is specified by performing an evaluation by both an approach search and an exit search prior to the route search or in parallel with the route search. A pull-in point in which one or both of the approach search and the exit search is not established is evaluated as being unusable for the route search, and the approach search and the exit search are executed again using other pull-in points as candidates.

  Here, the search start point and the search end point mean a start point and a goal point specified as route search conditions, and do not prescribe a route search algorithm. In the present invention, for example, an algorithm for searching for a route in parallel from both the search start point and the search end point may be applied.

  In the present invention, it may be allowed to use different pull-in points for the waypoints when entering and leaving. In the present invention, since each pull-in point can be entered and exited, even when different pull-in points are used, it is avoided that the two cannot be moved between the two. In addition, since it is a pull-in point provided for the same waypoint, even if the guided route is interrupted at first glance, it is relatively easy to find the method of moving between the pull-in points locally. There is no practical problem.

  In the present invention, any one pull-in point may be used for each waypoint. In other words, the route search may be performed using the pull-in points so that the via points and the pull-in points have a one-to-one relationship with respect to the via points where the pull-in points are set. In this way, a continuous route is guided in appearance.

  With regard to the pull-in points used for route search, candidates may be randomly selected from a plurality of pull-in points set for the waypoints, or candidates may be listed based on a certain selection rule. . In the latter case, for example, a selection rule that preferentially selects a pull-in point at a short distance from the waypoint may be applied. As a result, a route that passes through the vicinity of the waypoint can be obtained, and convenience is improved.

  When a plurality of service points are used for the waypoints, service points close to the departure point or destination may be used preferentially. In this way, it is possible to guide a route suitable for entering and leaving the waypoint. In order to avoid using an inconvenient pull-in point far from the waypoint, this selection may be made from among the pull-in points within a predetermined distance range from the waypoint.

  As another selection rule, for example, a rule that preferentially selects a pull-in point on a link or node that is not associated with traffic regulation information may be used. There is a high possibility that such a pull-in point can be obtained without any trouble from the starting point or the route from the previous pull-in point to the pull-in point and the route from the pull-in point to the next pull-in point or the destination. Therefore, the time required for route search can be shortened by preferentially setting such pull-in points as candidates.

  Another selection rule may be set based on a priority determined based on both the distance from the waypoint and the presence / absence of association of traffic regulation information. The priority can be arbitrarily set based on a fixed calculation formula using both evaluation values, such as an evaluation value based on distance and an evaluation value based on traffic regulation information, for example, and a weighted sum of both evaluation values. it can. Regardless of the calculation formula, a table that gives priority to both values may be prepared in advance. By doing so, it is possible to search for a route passing near the waypoint in a relatively short time.

  The approach search and the exit search can be performed in various modes. For example, when a plurality of waypoints are designated, the approach search is performed by using the waypoints to be evaluated as a search end point, (1) a method using the place immediately before that as a search start point, and (2) the entire departure Any of the methods using the ground as a search start point may be used. The approach search may be performed in the reverse direction from the waypoint to the departure point or the last waypoint. As for the exit search, either a method of setting a stop point as a search start point and (1) setting a stop point immediately after that as a search end point, or (2) a method using a whole destination as a search end point. It may be used.

  Furthermore, at least one of the approach search and the exit search may be a local search shown below. The local search for the approach search is performed from the waypoint side under the condition that the route conforms to the traffic restriction information when traveling in the reverse direction within a predetermined range including the waypoint, that is, the reverse interpretation of the traffic restriction information. It can be a route search. The local search for the exit search can be a route search performed from the waypoint according to the traffic regulation information within a predetermined range including the waypoint. By using the local search, there is an advantage that the time required for the entry search and the exit search, and thus the time required for the entire route search can be shortened.

  For example, as a local search in the approach search, a reverse search is performed from the waypoint to the departure place, and when the tip of the route goes out of the predetermined range from the waypoint, a method of determining that the approach search is successful is a method. Can be taken. This reverse search is performed while interpreting the traffic regulation so as not to conflict with the traffic regulation when the obtained route runs backward. The predetermined range can be defined by, for example, a linear distance from the waypoint, a road, the number of links, the number of nodes, and the like. If the predetermined range is expanded, the certainty that there is a route from the departure point to the pull-in point is improved, while the time required for the approach search is increased. The predetermined range can be arbitrarily set in consideration of the balance between certainty and required time.

  As a local search in the exit search, a forward search is performed from the waypoint to the destination, etc., and when the tip of the route goes out of the predetermined range from the waypoint, a method of judging that the exit search is successful is adopted. Can do. The predetermined range can be arbitrarily set based on the same criteria as the approach search.

  As another mode of the local search for the approach search, a route search may be performed with any point on the route from the departure point or the route point that should pass immediately before to the route point as a search start point. As another aspect, the local search for the exit search may be a route search in which any point on the route from the waypoint to the destination or the route place to pass immediately after is set as the search end point.

  The evaluation by the approach search and the exit search does not necessarily need to be performed for each pull-in point. For example, at least one of the entry search and the exit search may be omitted for a pull-in point on a link or node without traffic restriction information. This is because these route searches are likely to be successful for such pull-in points. By omitting this, it is possible to shorten the time required for determining whether the entry search and the exit search are successful.

  In the present invention, the route search can be performed in various modes other than the method described above. For example, after performing a route search under the same conditions as in the prior art, it may be evaluated whether a one-to-one relationship is maintained between the waypoints and the pull-in points. The route search may be repeatedly executed until a continuous route is obtained while sequentially changing the candidate pull-in points only for the transit points where such a relationship is not maintained.

  The present invention need not have all the various features described above, and some of them may be omitted or combined as appropriate. The present invention can be configured in various modes such as a route search device, a route search method using a computer, a computer program that realizes such route search, and a computer-readable recording medium that records the computer program. When configured as a route search device, it may be a stand-alone device or may be configured by connecting a terminal and a server via a network. Recording media include flexible disks, CD-ROMs, magneto-optical disks, IC cards, ROM cartridges, punch cards, printed matter printed with codes such as bar codes, computer internal storage devices (memory such as RAM and ROM), and Various media that can be read by a computer, such as an external storage device, can be used.

Embodiments of the present invention will be described in the following order.
A. System configuration:
B. data structure:
C. Route search (first embodiment):
C1. Overview of search methods:
C2. Route search process:
D1. Modification 1:
D2. Modification 2:
D3. Modification 3:
D4. Modification 4:
E. Route search (second embodiment):
F. Route search (third embodiment):

A. System configuration:
FIG. 1 is an explanatory diagram showing the overall configuration of a route guidance system as an embodiment. The route guidance system of the embodiment is configured by connecting a server 200 functioning as a route search device and a guidance device 100 used by a user via a network NET. As the network NET, for example, a mobile phone line can be used. The guidance device 100 is not limited to the illustrated example, and a plurality of guidance devices 100 can be connected to the server 200.

  The guidance device 100 can use an in-vehicle navigation device or a mobile phone. The functional blocks of the guide device 100 are also shown in the figure. These functional blocks are configured in software by causing a microcomputer mounted on the guide device 100 to execute a predetermined program, but may be configured in hardware.

  Each functional block implements the following functions under the control of the main control unit 110. The communication unit 120 controls communication via the network NET. The GPS 140 detects the latitude and longitude of the current position of the guidance device 100 using a global positioning system. The command input unit 130 inputs commands related to route search and route guidance based on a user operation on a switch or the like. The user can specify the starting point, the waypoint, and the destination of the route search by using a route search command. As the departure place, the current position detected by the GPS 140 may be used. These designations are transmitted to the server 200. The display control unit 150 displays a route search menu, a route guide map, and the like on the display of the guidance device 100.

  The server 200 performs a route search based on a command from the guidance device 100 and provides the result to the guidance device 100. Functional blocks for realizing such functions are shown in the figure. These functional blocks are configured in software by a computer program executed by the CPU of the server 200, but may be configured in hardware.

  The map DB 220 is an electronic map database used for route search and route guidance. In the present embodiment, the map DB 220 includes a road network DB 222 and a drawing DB 221. The road network DB 222 is a database used for route search, and records data indicating road connection states by links and nodes, traffic regulation information, and costs that are link evaluation values. The drawing DB 221 is data for displaying map information during route guidance. In addition to these databases, the map DB 220 may be provided with a search DB for assisting in setting a starting point and a destination for route search. The DB management unit 212 has a function of reading necessary data from the map DB 220 during route search and route guidance.

  The communication unit 202 controls communication with the guidance device 100 via the network NET. The information to be communicated includes a start point, a destination, a waypoint designation, other route search commands, and a route search result. The point input unit 204 receives the designation result of the departure point, the destination, and the waypoint via the communication unit 202 and records each in the pull-in point management table 208. The pull-in point management table 208 is a table for managing various pieces of point information to be used in the route search in this way. Its configuration will be described later.

  The pull-in point setting unit 210 sets a pull-in point for points that deviate from links and nodes among the departure point, destination, and waypoint. The pull-in point refers to an alternative point set on a link and a node around each point such as a departure point. Although the method of setting the pull-in point is arbitrary, in this embodiment, the perpendicular foot drawn on each link existing around the departure point or the like is set as the pull-in point. There may be a plurality of service points for each departure point.

  The route search unit 206 performs a route search with reference to the drawing point management table 208 and the map DB 220 based on a command designated by the user. For the route search, for example, a known method such as the Dijkstra method can be used. The obtained route is transferred to the search result output unit 214. The search result output unit 214 outputs a map and guidance information necessary for route guidance to the guidance device 100 with reference to the route search result and the map DB 220.

B. Data structure (road network DB and service point management table):
FIG. 2 is an explanatory diagram showing the data structure of the road network DB 222 and the pull-in point management table 208. An example of a link and a node corresponding to a road is shown in the center of the figure, an example of the structure of the road network DB 222 is shown above, and an example of a pull-in point management table 208 is shown below.

  In the example at the center of the figure, the road connection state is represented by links L1 to L7 and nodes N1 to N6. A node corresponds to a connection point between links. In this example, the links L1 to L7 are linear, but it is also possible to set a polygonal link by specifying a plurality of link point coordinates. The link L4 is set with a one-way traffic restriction called Tr1. This traffic regulation is synonymous with the prohibition of traffic along the arrow a1, ie, “node N2 → N3 → N6”, and traffic along the arrow a2, ie, “node N4 → N3 → N6”. is there.

  The road network DB 222 has node data 222a and link data 222b. The node data 222a records latitude, longitude position information, and traffic regulation information for each node. For example, with respect to the node N3, position information “(latitude, longitude) = (Lat3, Lon3)” is recorded, and the passage restriction information includes a passage method incapable of passage, in this example, “node N2 → N3” described above. → N6 ”and“ node N4 → N3 → N6 ”are recorded.

  The link data 222b records position information and cost for each link. The position information records the start and end nodes. A plurality of coordinate values of points through which links pass may be designated between these nodes. The cost is an evaluation value of each link used in the Dijkstra method, which is a method of route search. The link data 222b may further include information specifying a link connected to each link.

  The pull-in point management table 208 is a table for managing information on each point used in route search. The starting point ST, the waypoint V1, other waypoints, and the destination DST are arranged in the order in which they should pass. The position of each point is recorded with the code of the node or coordinate values of latitude and longitude. In the example of the figure, the positions of the departure point ST and the destination DST are recorded with the code of the node, and the position of the waypoint is recorded with coordinates.

  If the departure point, waypoint, or destination is off the link or node, a pull-in point is set. The pull-in point information (hereinafter also referred to as “pull-in point list”) of the pull-in point management table 208 records the position coordinates of the pull-in points associated with each point and the availability of the route search. In the example shown in the figure, pull-in points P11 and P12 are set for the waypoint V1. However, the latitude and longitude of each pull-in point are not shown in the figure. The availability indicates whether the route search can be used. “NA” represents not available, and “A” represents available. The availability is attached in the course of the route search, and in an initial state after setting the pull-in point, it is unified as “Null” without any information or “A”.

  The road network DB 222 and the pull-in point management table 208 only have to record the above information, and the data structure itself is not limited to the example shown in FIG. 2, and various structures can be applied.

C. Route search (first embodiment):
C1. Outline of route search method:
FIG. 3 is an explanatory diagram showing an outline of the route search method. Description will be made by taking the road connection state shown in FIG. 2 as an example. First, consider a case where a route search from the departure point ST to the waypoint V1 is performed in such a road configuration. The route search toward the waypoint in this way is hereinafter referred to as an approach search. Since the waypoint V1 is not on the link, the route search is performed using either the pull-in point P11 or P12 as the search end point. A route cannot be obtained for the pull-in point P11 due to the one-way restriction Tr1 of the link L4. Therefore, as a search result from the departure point ST to the waypoint V1, a route R1 having the pull-in point P12 as a search end point is obtained.

  Next, a route search from the waypoint V1 to the destination DST is executed. The route search from the waypoint to the next point is hereinafter referred to as an exit search. When this exit search is performed independently of the approach search, in the exit search, a route R3 from the retract point P11 different from the retract point P12 used in the approach search to the destination DST may be obtained as a solution. In the present embodiment, in order to avoid such a result, the route R2 is obtained by executing the exit search using the same pull-in point P12 as the entrance search. As a result, as a whole, a continuous route from the departure point ST to the pull-in point P12 by the route R1 and then from the pull-in point P12 to the destination DST by the route R2 is obtained.

  As described above, in this embodiment, the route search is performed under the condition that one pull-in point is used for each waypoint, in other words, the route point and the pull-in point have a one-to-one correspondence. Execute. Hereinafter, an algorithm for realizing such route search will be described.

C2. Route search process:
FIG. 4 is a flowchart of route search processing. This is a process realized by linking the functional blocks of the server 200, and is a process executed by the CPU of the server 200 in terms of hardware.

  When the process is started, the server 200 inputs designation of a departure point, a destination, and a waypoint based on a user operation on the guidance device 100 (step S10). Then, these designated points are registered in the pull-in point management table 208, the pull-in points are set for points that do not exist on the link or node, and a pull-in point list is created (step S11).

  Next, the server 200 executes a process for determining a pull-in point used for the route search for each waypoint (step S20). First, one is selected as a candidate from the pull-in points associated with a route point to be processed (hereinafter referred to as “target route point”) (step S30). This selection is performed by various methods, such as a method of selecting at random, a method of selecting in order of distance from the transit point, a method of selecting in order from a link or node with no traffic restriction information, or a pull-in point set on a node. Can do. In the present embodiment, a method of preferentially selecting as a candidate in order from the shortest distance is adopted. The drawing points selected in this way are hereinafter referred to as “candidate drawing points”.

  Next, the server 200 performs an approach search for the candidate pull-in points (step S40). In the approach search, a departure point is set as a search start point, a candidate pull-in point is set as a search end point, and a route search is executed. If the route search fails (step S50), the information about the candidate pull-in point is updated to “NA” that cannot be used in the pull-in point management table 208 (step S53), and the process is repeated again for other candidate pull-in points. (Steps S30 to S50).

  If the search is successful (step S50), an exit search is executed for the same candidate pull-in point (step S51). In the exit search, the route search is executed by setting the candidate pull-in point as the search start point and the destination as the search end point. If the route search fails (step S50), the information about the candidate pull-in point is updated to “NA” that cannot be used in the pull-in point management table 208 (step S53). Repeat the process. If the exit search is successful, the candidate pull-in point is determined as a point that can be used for the route search (step S54), and information on this candidate pull-in point is changed to “A” that can be used in the pull-in point management table 208. .

  By executing the above processing for each waypoint (step S60), the pull-in point to be used for the route search is determined. The server 200 performs a route search using the pull-in points set in this way (step S62). In this route search, the route from the departure point to the first route point, the first route point to the second route point,...

  According to the present embodiment, for each waypoint, since the pull-in points set in the processing up to step S60 are used, a continuous route, a route that can actually be moved, is always obtained. Improved convenience.

D1. Modification 1:
FIG. 5 is a flowchart of a pull-in selection process as a modification. This is a process instead of step S30 in the embodiment (FIG. 4). In the modification, a process of selecting a candidate pull-in point in consideration of both the distance between the pull-in point and the waypoint and the presence / absence of traffic restriction information is shown.

  In the process of the modified example, for all the pull-in points, first, the distance D between the pull-in point and the waypoint is calculated (step S33), and the evaluation value Vd is calculated based on this distance (step S34). The higher the evaluation value, the higher the priority as a candidate pull-in point. In the figure, the relationship between the distance D and the evaluation value Vd is illustrated. The relationship between the two can be arbitrarily set. For example, if the distance is set as a straight line C1, the evaluation value Vd decreases linearly as the distance D increases. = 0 ". If it is set as shown by the curve C2, the evaluation value Vd of the pull-in point very close to the waypoint becomes very large. If set as shown by the curve C3, the evaluation value Vd is substantially constant in the vicinity of the stopover point, but the evaluation value Vd decreases rapidly if it is slightly out of the range. In the curves C2 and C3, there is a tendency that the pull-in points near the waypoints are relatively easily selected.

  Next, the server 200 calculates an evaluation value Vr based on traffic restrictions (step S35). In this example, “evaluation value Vr = 0.5” is set when there is a restriction, and “evaluation value Vr = 1.0” is set when there is no restriction. Both values can be set arbitrarily. The evaluation value Vr may be set to 0 when there is a restriction.

Based on the evaluation values Vd and Vr thus obtained, the server 200 calculates the evaluation value Vv of the candidate pull-in point by the following equation (1) (step S36).
Vv = k1 * Vd + k2 * Vr;
k1 and k2 are weighting factors (real numbers) (1)

  The value of the weighting factor can be set arbitrarily. Either one may be set to the value 0. For example, if k1 is a value of 0, the evaluation value Vv is determined only by the presence or absence of traffic restrictions. If k2 is a value of 0, on the contrary, the evaluation value Vv is determined only by the distance from the waypoint.

  The server 200 obtains the evaluation value Vv by the above-described method for all the drawing points (step S37), and selects the drawing point having the maximum evaluation value Vv (step S38). According to the method of the modified example, it is possible to select a candidate pull-in point in consideration of both the distance from the waypoint and the traffic regulation.

D2. Modification 2 FIG. 6 is a flowchart of route search processing as a modification. Only the process replacing step S40 in the embodiment (FIG. 4) is shown. In the embodiment, the approach search is performed between the departure point ST and the candidate pull-in point, whereas in the modified example, the route search from the pull-in point toward the departure point ST is performed, and the route to the departure point ST is determined. A local search is performed to determine the success or failure of the approach search at a point before being completely determined.

  When this process is started, the server 200 sets a pull-in point as a search end point (step S40a). Then, the search is executed in the reverse direction from the search end point side (step S40b). This search can be performed by the Dijkstra method or the like. Since the search is in the reverse direction, traffic restrictions are taken into account so that they do not violate when the route obtained is reversed. This search may be performed in a mode of randomly extending the route, but it is more preferable to emphasize the direction of the departure point ST and to extend the route from the end point of the search toward the departure point ST.

  When the length of the searched route is equal to or longer than the predetermined length Th (step S40c), the server 200 determines that the search is successful (step S40d) and ends the approach search process. In this modification, the path length is evaluated by the number of links, and “Th = 10” is set. That is, it is determined that the search is successful when the number of links on the route extends to 10 or more. The determination reference value Th can be arbitrarily set. The determination in step S40c can take various forms. For example, the linear distance between the searched route end and the drawing point, the path from the drawing point to the route end, and the predetermined length Th A comparison may be made.

  When the length of the searched route does not reach the predetermined length Th (step S40c), it is determined whether or not a search stop condition is satisfied (step S40e). As the stop condition, for example, the required time exceeds a predetermined value, or there is no longer a stretchable path can be used. If the search stop condition is satisfied, the server 200 determines that the search has failed (step S40f), and ends the approach search process. Until the search stop condition is satisfied, the route search is executed again (step S40b). In the modified example, since the local search is used in this way, the success or failure of the approach search can be determined in a short time, and thus the time required for the route search can be shortened.

  Similarly, a local search may be applied to the exit search. In this case, in step S40a of FIG. 6, the search start point is set as the pull-in point and the search end point is set as the destination, and in step S40b, forward search is performed from the search start point toward the shelving end point. do it. The local search may be applied to both the approach search and the exit search, or may be applied to only one of them.

D3. Modification 3:
FIG. 7 is a flowchart of route search processing as a modified example of local search. Only the processing in place of steps S30 to S50 in the embodiment (FIG. 4) is shown. In the embodiment, the approach search is performed between the departure point ST and the candidate pull-in point, whereas in the modified example, the approach search is executed using a point closer to the waypoint than the departure point ST.

  In this process, the server 200 determines whether or not the route search for the candidate pull-in point is the first time (step S41). In the case of the first time, the entry search is executed using the departure point ST as the search start point and the candidate pull-in point as the search end point as in the embodiment (steps S42 and S44). In the second and subsequent processes, an approach search is executed using N nodes before the waypoint as a search start point (steps S43 and S44).

  An example of this process is shown below the figure. Consider a case where the pull-in points P11 and P12 are set for the waypoint V1. As for the priority as a candidate, it is assumed that the pull-in point P11 is higher than the pull-in point P12.

  In this state, in the first process, a route search is performed with the search start point as the departure point ST and the search end point as the candidate pull-in point P11 to obtain a thick solid route R1. For example, if the exit search is unsuccessful with respect to the candidate pull-in point P11, next, the approach search is performed with respect to the candidate pull-in point P12. In this case, as shown in step S43, a node N before the waypoint is set as a search start point. In the example of the figure, a case is shown in which the previous three nodes N3 are used as the search start point along the already obtained route R1. The approach search is a local search between the node N3 and the candidate pull-in point P12, and a route R2 is obtained. By using the local search in this way, the time required for the search is shortened, so that the success or failure of the approach search can be quickly determined for each candidate pull-in point. Here, an example of “3 before” is shown, but the search start point in the local search can be arbitrarily set within the route range that passes in common from the departure point ST even when the candidate pull-in point is changed. It is.

  In FIG. 7, the case where the local search was utilized for the approach search was illustrated. Similarly, a local search can be applied to an exit search. In this case, the candidate pull-in point can be used as the search start point, and for example, a node that has moved N from the candidate pull-in point to the destination can be used as the search end point. The local search may be applied to both the approach search and the exit search, or may be applied to only one of them.

D4. Modification 4:
FIG. 8 is a flowchart of route search processing as another modification. Only step S11 and subsequent steps of the embodiment (FIG. 4) are shown. In the embodiment, the entry search is performed unconditionally for the candidate pull-in points, but in this modification, the entry search is omitted depending on the conditions. That is, it is determined whether or not there is a traffic restriction for the link or node for which the candidate pull-in point is set (step S40p). If there is no traffic restriction, it is determined that there is a high possibility that both the entry search and the exit search will be successful, and these processes are omitted to determine the pull-in point (step S54). When the traffic restriction is set, the route search may fail, so the entrance search and the exit search are inspected by the same processing as in the embodiment (FIG. 4).

  According to the process of this modified example, since the entry search and the exit search can be omitted under a certain condition, there is an advantage that the pull-in point used for the route search can be quickly determined.

E. Route search (second embodiment):
FIG. 9 is a flowchart of route search processing as the second embodiment. In the first embodiment (FIG. 4), an example is shown in which a route search is performed again after determining the pull-in points used for the route search for each waypoint. In contrast, in the second embodiment, an example in which the route search and the determination of the pull-in point are performed in parallel will be described with reference to the road configuration of FIG. 3 as appropriate.

  In this process, the departure point is represented as a transit point [0], the intermediate transit point is represented as a transit point [1], [2]... [N-1], and the destination is represented as a transit point [n] (n is a natural number). And When the process is started, the server 200 inputs designation of these points (step S100). Then, similarly to the first embodiment (FIG. 4), a pull-in point list is created (step S102).

  Next, an initialization process is performed in which a value of 1 is assigned to a control variable used for executing the route search process (step S104), and the route search is executed according to the following procedure. First, a pull-in point [i-1] is determined for the waypoint [i-1] (step S106). When this process is executed for the first time (when i = 1), the transit point [0], that is, the pull-in point [0] associated with the departure point is determined. When the departure point is on the node, it is handled as “pull-in point [0] = departure point [0]”.

  Next, the server selects a candidate pull-in point [i] for the waypoint [i] (step S108). If it demonstrates in connection with the example of FIG. 3, either one of drawing-in points P11 and P12 will be selected as a candidate drawing-in point [1] of waypoint [1]. Various methods can be applied to the selection as in the first embodiment. Here, it is assumed that the nearest pull-in point P11 of the waypoint V1 is selected. The server 200 performs an approach search using the two pull-in points set in this way (step S110).

  In this approach search, a pull-in point [i-1] is set as a search start point, and a pull-in point [i] is used as a search end point. This search can be substantially regarded as an exit search for the pull-in point [i-1]. The first embodiment (FIG. 4) uses the starting point as a search start point, whereas the second embodiment is different in that the search start point also varies. That is, in the second embodiment, the approach search is executed for each section divided by waypoints. When “i = 1”, in the example of FIG. 3, an approach search is performed between the departure point ST corresponding to the pull-in point [0] and the pull-in point P11 corresponding to the pull-in point [1].

  When this route search is unsuccessful (step S112), and when all the pull-in points [i] have not been examined for the route point [i] (step S130), the pull-in point management table 208 is similar to the embodiment. The content is updated (step S132), and the same processing is executed for the next candidate pull-in point.

  For example, in the example of FIG. 3, the route search between the departure point ST and the pull-in point P11 ends unsuccessfully, but another pull-in point P12 still remains for the waypoint V1. Accordingly, in the service point management table 208, “NA” is recorded as “unusable” for the service point P11, and then the service point P12 is selected as the service point [1] (step S108), and the approach search is retried. To do.

  If the route search is successful (step S112), it means that the route [i] can be reached. Therefore, the control variable i is incremented by 1 (step S120), and "i> n", that is, the destination is reached. If it is determined that it has not been reached (step S122), the above-described processing is executed again.

  In the example of FIG. 3, as a process after the control variable is incremented to the value 2, the pulling point [1] for the waypoint [1] is fixed to P12 (step S106), That is, the destination DST is selected (step S108), and an entry search is performed between them (step S110). If these route searches are successful (steps S112, S120, S122), a route from the departure point ST to the destination DST is obtained.

  In the above-described processing, there may be a case where the approach search is unsuccessful for all the pull-in points associated with the waypoint [i] (step S130). In such a case, in the second embodiment, the process is retried retroactively to the setting of the pull-in point [i-1] at the waypoint [i-1]. First, in the pull-in point management table 208, all the information on the unusable “NA” attached to the pull-in point associated with the route point [i] is reset and the pull-in point determined for the route point [i−1]. Unusable “NA” is set for [i−1] (step S134). Thereafter, the control variable is decremented by 1 and the route search (after step S106) is retried.

  In FIG. 3, “i = 2”, that is, a case where an approach search is performed between the pull-in point P12 and the destination is considered (step S110). If this route search is unsuccessful, all the information on the pull-in point [i] associated with the waypoint [i] (that is, the destination) is reset in the pull-in point management table 208 (step S134). Further, the information of the pull-in point [i-1] (that is, the pull-in point P12) of the waypoint [i-1] is set to unusable “NA” (step S134). Thereafter, the control variable is set to “i = 1” and the route search is executed again. That is, the route search between the departure point ST and the waypoint V1 is retried. In the example of FIG. 3, only two pull-in points P11 and P12 are shown for the waypoint V1, but if there are other pull-in points, an approach search is performed for this pull-in point.

  According to the route search of the second embodiment, the entire route can be obtained at the time when the pull-in point of each waypoint is determined, and it is possible to reduce the processing time because the entire route can be obtained. . Also in the second embodiment, the selection rule in consideration of the distance between the pull-in point and the waypoint, the presence / absence of traffic restrictions, and the like can be applied to the selection of the pull-in point in step S108.

F. Route search (third embodiment):
FIG. 10 is a flowchart of route search processing as the third embodiment. In the third embodiment, an example in which a plurality of service points are allowed to be used together for each waypoint is shown.

  When this process is started, the server 200 sets a departure point, a destination, and a waypoint as in the first embodiment (FIG. 4) (step S200), and creates a pull-in point list (step S202). And the success or failure of an approach search and an exit search is evaluated about all the drawing points (steps S204-S216). When one of the entry search and the exit search fails, the unavailable point “NA” is recorded in the pull-in point management table (step S214). Since these processes are the same as those in the first embodiment (FIG. 4), detailed description thereof is omitted. In the first embodiment, for each waypoint, when a pull-in point where both the entry search and the exit search are successful is found, the process proceeds to the next route point. Evaluate entry and exit searches for points. Various methods shown in the first embodiment and the modification examples can be applied to the approach search and the exit search.

  When the processing is completed for all the pull-in points, the server 200 determines the pull-in points to be used at the time of route search for each waypoint from the pull-in points evaluated as usable, that is, the pull-in points where both the entry search and the exit search are successful. Then (step S220), a route search is executed (step S240).

  FIG. 11 is a flowchart of the pull-in point determination process. This process corresponds to step S220 in FIG. In this process, the server 200 executes the following process for all waypoints (step S222). First, the server 200 refers to the drawing point management table (step S224) and checks the number of available drawing points. If there is only one pull-in point (step S226), the pull-in point is determined as a point used for route search (step S228), and the process proceeds to the next waypoint processing (step S234).

  If there are a plurality of available pull-in points (step S226), the distance D from the current via-point and the distance Dp from the previous via-point for all available pull-in points associated with the via-point. Then, the distance Dn to the immediately following waypoint is calculated (step S230). Then, the pull-in point with the smallest “D + Dp” is determined as the pull-in point when entering the transit point, and the pull-in point with the smallest “D + Dn” is determined as the pull-in point when leaving the transit point. Then (step S232), the process proceeds to the next waypoint processing (step S234). The entry points used may be the same or different when entering and leaving.

  In the figure, the method for determining the pull-in point at the time of entry is illustrated. It is assumed that two pull-in points P21 and P22 are available for the waypoint V22. The transit point immediately before the transit point V22 is V21, and the transit point immediately after it is V23. The thick line in the figure represents a link, and the black circle represents a node. For the pull-in point P21, the distance from the waypoint is D21, and the distance from the immediately preceding route V21 is Dp21. For the pull-in point P22, the distance from the waypoint is D22, and the distance from the immediately preceding route V21 is Dp22. In this case, since “D21 + Dp21 <D22 + Dp22”, the entry point P21 is used when entering the waypoint V22.

  Similarly, if each pull-in P21, P22 is evaluated by using the distance between the via-point V23 immediately after the via-route V22 and the pull-in points P21, P22, and the distances D21, D22, when pulling out from the via-point V22 Point P22 will be used.

  In the third embodiment, the above-described evaluation is performed for all available pull-in points. However, the above-described evaluation is performed only for the available pull-in points that are within a predetermined distance from the waypoint. May be. In 3rd Example, although the example which performs evaluation of the drawing points P21 and P22 based on the straight line distance with the waypoints V21 and V23 was shown, the time required from these waypoints to the drawing point, link cost, way, etc. May be used alone or in combination to evaluate the pull-in point.

  According to the processing of the third embodiment described above, route guidance using a plurality of pull-in points is permitted for each waypoint. However, unlike the prior art, only the pull-in points that allow both entry and exit are used for route guidance. In such a case, even when different pull-in points are used at the time of entry into and exit from the waypoint, it is almost guaranteed that movement between the pull-in points is possible. Even if the guided route is seemingly interrupted, the movement method between these pull-in points can be found relatively easily on site, and there is no practical problem. According to the third embodiment, for example, when going through a parking lot, it is possible to guide to exit from an exit different from the entrance at the time of entry, and it is possible to guide an efficient route with a short moving distance.

  As mentioned above, although the various Example of this invention was described, it cannot be overemphasized that this invention is not limited to these Examples, and can take a various structure in the range which does not deviate from the meaning. In the above-described embodiment, the system including the guidance device 100 and the server 200 is illustrated, but the present invention can also be configured as a stand-alone device.

It is explanatory drawing which shows the whole structure of the route guidance system as an Example. It is explanatory drawing which shows the data structure of road network DB222 and the drawing-in management table 208. FIG. It is explanatory drawing which shows the outline | summary of the route search method. It is a flowchart of a route search process. It is a flowchart of the drawing selection process as a modification. It is a flowchart of the drawing selection process as a modification. It is a flowchart of the route search process as a modification. It is a flowchart of the route search process as another modification. It is a flowchart of the route search process as 2nd Example. It is a flowchart of the route search process as 3rd Example. It is a flowchart of a drawing-in point determination process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Guide apparatus 110 ... Main control part 120 ... Communication part 130 ... Command input part 140 ... GPS
DESCRIPTION OF SYMBOLS 150 ... Display control part 200 ... Server 202 ... Communication part 204 ... Point input part 206 ... Path | route search part 208 ... Pull-in point management table 210 ... Pull-in point setting part 212 ... DB management part 214 ... Search result output part 220 ... Map DB
221: Drawing DB
222 ... Road network DB
222a ... Node data 222b ... Link data

Claims (9)

A route search device,
A database reference section for referring to road network data comprising a link, a node, and traffic restriction information associated with the link or the node;
A point input unit for inputting a starting point of a route search, a destination, and at least one waypoint;
For route search, for a transit point that is not on the link or node, a pull-in point setting unit that sets a plurality of pull-in points on behalf of the transit point on any link or node; and
A condition of using a pull-in point that uses both an entrance search that searches for a route with a pull-in point as a search end point and an exit search that searches for a route with the pull-in point as a search start point for each of the transit points. A route search apparatus comprising: a route search unit that searches for a route that passes through the departure point, any of the pull-in points, and a destination based on the road network data so as to satisfy The route search device according to claim 1,
The route search unit is a route search device that uses any one pull-in point for each of the waypoints. The route search device according to claim 1,
The route search unit is a route search device that preferentially selects a pull-in point at a short distance from the waypoint among the multiple pull-in points. The route search device according to claim 1,
The route search unit is a route search device that preferentially selects a link or a pull-in point on a node that is not associated with the traffic restriction information among the multiple pull-in points. The route search device according to claim 1,
The route search unit is a route search device that makes a candidate a pull-in point with a high priority determined based on both the distance from the waypoint and the presence / absence of association of the traffic regulation information among the pull-in points at the plurality of locations. . A route search device according to any one of claims 1 to 5,
At least one of the approach search and the exit search is performed by a local search;
The local search for the approach search is a route search performed from the waypoint side on the condition that the route is suitable for the traffic regulation information when traveling in the reverse direction within a predetermined range including the waypoint. ,
The route search device is a route search in which the local search for the exit search is a route search performed from the waypoint according to the traffic regulation information in a predetermined range including the waypoint. The route search device according to claim 6,
The route search device, wherein the route search unit omits at least one of the approach search and the exit search for a pull-in point on a link or node without the traffic restriction information. As a route search method, which is executed by a computer,
A database reference step for referencing road network data comprising links, nodes, and traffic control information associated with said links or nodes;
A point input process for inputting the starting point of the route search, the destination, and at least one waypoint;
For route search, for a transit point that is not on the link or node, a pull-in point setting step for setting a plurality of pull-in points on behalf of the transit point on any link or node;
A condition of using a pull-in point that uses both an entrance search that searches for a route with a pull-in point as a search end point and an exit search that searches for a route with the pull-in point as a search start point for each of the transit points. A route search method comprising: a route search step for searching for a route that passes through the departure point, one of the pull-in points, and a destination based on the road network data so as to satisfy A computer program for performing a route search by a computer,
Database reference program code for referencing road network data comprising links, nodes, and traffic control information associated with the links or nodes;
Program code for point input that inputs the starting point, destination, and at least one waypoint for route search,
For route search, for route points that are not on the link or node, on any link or node, a program code for setting a pull-in point that sets a plurality of pull-in points instead of the route point,
A condition of using a pull-in point that uses both an entrance search that searches for a route with a pull-in point as a search end point and an exit search that searches for a route with the pull-in point as a search start point for each of the transit points. A computer program comprising: a route search program code for searching for a route passing through the departure point, any of the pull-in points, and a destination based on the road network data so as to satisfy