JP5639776B2 - Route search system - Google Patents

Description

  The present invention relates to a route search system that searches for a route to an alternative destination that can be used when heading to a specified destination.

  2. Description of the Related Art Navigation systems that search and guide a route from a specified departure point to a destination using network data that expresses roads as links and nodes have become widespread. When using a navigation system when moving by car, there is no guarantee that there is a parking lot at the destination. Therefore, use the parking lot around the destination as an alternative destination, and search and guide the route to this alternative destination. It is preferable.

  Conventionally, a parking lot around the destination has been searched in the following procedure. A node at the shortest distance to the destination is found on the network data used for the route search, and a parking lot close to the above-mentioned node is found by performing a route search using the network data with this node as the departure point.

  As another method, Patent Document 1 discloses a technique for searching for a parking lot within a predetermined distance range from a destination. When a plurality of parking lots are searched for within a predetermined distance range, a parking lot to be searched for a route is determined based on congestion information, full vehicle information, etc. of the parking lot.

JP 2007-263581 A

FIG. 1 is an explanatory diagram showing a parking lot search method in the prior art.
Consider a case in which when a destination H0 is designated, a nearby parking lot is searched. From the destination H0, it can reach the road R02 through a narrow passage. The road R02 intersects with roads R00 and R01 located beyond the river RV. Links L00 and L01 and a node N for use in route search are set on the roads R00 and R01. Around the destination, there is a parking lot PK1 facing the road R00, and there is a parking lot PK2 facing the road R02.
In the prior art, the parking lot is searched by route search starting from the node N at the shortest distance from the destination H0. As shown in the figure, since the network data is only maintained on the roads R00 and R01, a route search is performed along the link L00 in the direction of the arrow P, and the parking lot PK1 is selected as a parking lot to be guided.
Even if the network data is maintained on the road R02, the parking lot PK1 close to the node N is still selected as long as the node N is the starting point.

  Further, as described in Patent Document 1, even if the parking lot is selected based on the distance from the destination H0, the distance D1 to the parking lot PK1 is shorter than the distance D2 to the parking lot PK2. The parking lot PK1 is selected.

However, as is apparent from the road conditions in the figure, it is not the parking lot PK1 but the parking lot PK2 that is convenient when going to the destination H0. Thus, in the prior art, a convenient parking lot is not always selected for the destination H0.
The above-mentioned problem is common not only when the parking lot is used as an alternative destination but also when other alternative destinations are used. The present invention has been made in view of such a problem, and an object thereof is to enable guidance to an alternative destination with high convenience based on the state of a road around the destination.

The present invention can be configured as a route search system that searches for a route to an alternative destination that can be used when heading to a specified destination. An alternative destination is a place where a user stops a moving means such as a parking lot when heading to a destination by car, a bicycle parking lot when heading by bicycle, or a horse riding ground when heading by horse. It can be. Also, if you want to buy a souvenir at a flower shop or confectionery before you get to your destination, or if you want to spend time at a coffee shop or restaurant, you can use these stores as alternative destinations.
In the present invention, these alternative destinations are not instructed to the user in advance. The present invention searches for alternative destinations that the user wants to use around the destination and then searches for a route to the alternative destination.
In the present invention, the attributes of these alternative destinations may be determined in advance or specified by the user.

The route search system includes a map database storage unit, an input unit, an arrival point acquisition unit, an alternative destination search unit, and a route search unit.
The map database storage unit stores network data representing roads as nodes and links, and feature data for storing polygons for drawing features including roads. Network data can be prepared by mixing a main network that can be used for route search of automobiles in consideration of traffic regulations and a quasi network that can be used for route searches but cannot be completely developed for traffic regulations. Good.

  The input unit inputs designation of a departure place and a destination. As the departure place, the current position of the user may be automatically input. As the destination, a specific building or the like included in the feature data may be specified, or a coordinate value may be specified on the map. The input unit may further input attributes of alternative destinations such as a parking lot and a store.

The arrival point acquisition unit refers to a map database including network data and feature data, and is a point on the road where the network data is prepared as the above-described main network, that is, a road through which automobiles can pass. An arrival point that is a point that can be reached through a road from a feature corresponding to is acquired.
The arrival point may be set for each feature such as a building as a part of the feature data. In this case, the arrival point acquisition unit need only read the arrival point data corresponding to the feature designated as the destination. When the destination is designated by the coordinate value, the arrival point acquisition unit may identify the feature corresponding to the designated coordinate and read the data of the arrival point corresponding to the feature.
On the other hand, it can also be set as the structure which does not prepare an arrival point beforehand. In this case, the arrival point acquisition unit finds the arrival point by route search starting from the destination. For route search in this case, it is possible to use a quasi-network where traffic regulations are not completely developed, and roads where no network is established. For roads that do not have a network, it is possible to search for a route by treating the degree of connection of polygon data of roads included in the feature data as network data.

The alternative destination search unit searches for an alternative destination having a predetermined attribute that can be reached from the arrival point by performing a route search starting from the arrival point with reference to the network data. When the alternative destination is searched, the route search unit searches the route from the departure point to the searched alternative destination with reference to the network data.
The search for an alternative destination may use only the main network, or may use a quasi-network or road polygon data in combination. When only the main network is used, since the alternative destination should be associated with the main network, the route search unit may perform the route search from the departure point by regarding the alternative destination as it is. .
When the quasi-network and road polygon data are used in combination, the alternative destination is not necessarily associated with the main network. Therefore, the route search unit acquires an arrival point for the alternative destination, and performs a route search from the departure point by regarding this arrival point as the destination.

  According to the route search system of the present invention, an alternative destination is searched from an arrival point corresponding to the destination. The arrival point is not simply the shortest distance from the destination, but is set in consideration of the road conditions from the destination. Therefore, alternative destinations that are highly convenient can be set.

In the present invention, when a plurality of alternative destinations are searched, a route search from the departure point may be performed for all, but any of the searched alternative destinations is prioritized according to the following mode. May be. Priority means selecting only one alternative destination or narrowing down several candidates for route search among a plurality of alternative destinations.
As a first aspect, priority may be given to an alternative destination having a short distance from the arrival point to the alternative destination. By doing so, the distance from the alternative destination to the destination can be shortened.
As a second aspect, priority may be given to an alternative destination where the route from the arrival point to the alternative destination overlaps in part or in whole with the route from the destination to the arrival point. An alternative destination may be searched on the opposite side of the arrival point across the destination. Such alternative destinations may be highly convenient in that they can reach the destination without returning from the alternative destination to the arrival point. As described above, it is possible to give priority to an alternative destination on the opposite side of the arrival point across the destination by considering the overlap of the route.
The first aspect and the second aspect may be applied together.

The search for an alternative destination may use road polygon data included in the feature data in addition to the network data. That is, the search using the main network, the quasi-network, and the polygon may be performed.
By doing so, the range of search is expanded, and it becomes easier to search for a more appropriate alternative destination.
Even if the traffic regulations for the quasi-network and polygons are not sufficiently developed, vehicles may be able to pass on roads with parking lots or roads with sufficiently wide lanes. When searching for alternative destinations using these data in combination, it can be used for searching after determining whether or not traffic is possible based on the features existing along the road and the attributes of the road. You may make it narrow down a road.

  In addition, the present invention may be configured as a route search method using a computer, or may be configured as a computer program for causing a computer to execute such route search. Moreover, you may comprise as a computer-readable recording medium which recorded such a computer program. 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.

It is explanatory drawing which shows the search method of the parking lot in a prior art. It is explanatory drawing which shows the structure of a route search system. It is explanatory drawing which shows the structure of a map database. It is explanatory drawing shown about the setting of an arrival point. It is a flowchart of a route search process (1). It is a flowchart of a route search process (2). It is explanatory drawing which shows the search example (1) of an alternative destination. It is explanatory drawing which shows the search example (2) of an alternative destination.

Embodiments of the present invention will be described in the following order.
A. System configuration:
B. data structure:
B1. Network data:
B2. Character data:
B3. Feature data:
B4. Character data:
C. Route search process:
D. Route search example

A. System configuration:
FIG. 2 is an explanatory diagram showing the configuration of the route search system. The route search system is configured as a navigation device 100. In this embodiment, the navigation apparatus 100 is connected to the server 200 that provides map data and the like through the network NE, and can receive the update of the map database from the server 200. The navigation device 100 may be configured to operate stand-alone, or may be configured to execute part of its functions on the server 200 or the like.

  The server 200 includes a map database storage unit 210, a transmission / reception unit 201, and a database management unit 202. Although the transmission / reception unit 201 and the database management unit 202 may be configured in hardware, in this embodiment, the transmission / reception unit 201 and the database management unit 202 are configured in software by installing a computer program that realizes these functions.

The transmission / reception unit 201 communicates with the navigation device 100 via the network NE. In the present embodiment, data stored in the map database storage unit 210, a command for requesting provision thereof, and the like are communicated.
The database management unit 202 reads the map information requested from the navigation device 100 from the map database storage unit 210. The map database storage unit 210 stores feature data 211, character data 212, and network data 213.
The feature data 211 is polygon data of features to be drawn on a map such as roads and buildings. The character data 212 is character information to be displayed on the map. For example, text information such as a building name and a place name is included. The network data 213 is data representing roads as nodes and links.

The navigation device 100 includes various functional blocks that operate under the main control unit 101. In the present embodiment, the main control unit 101 and each functional block are configured by installing software that realizes the respective functions, but part or all of them may be configured by hardware.
The transmission / reception unit 102 communicates with the server 200 via the network NE. In this embodiment, transmission / reception of a map database and a command for receiving the map database are mainly performed.
The command input unit 103 inputs an instruction from the user through operations of buttons, levers, touch panels, and the like provided in the navigation device 100. Examples of instructions in the present embodiment include designation of a starting point and a destination for route search.
The GPS input unit 104 inputs a user's current position using GPS (Global Positioning System).
The map database storage unit 105 stores a map database stored in the map database storage unit 210 provided from the server 200. In the present embodiment, the entire map database included in the server 200 is also stored in the map database storage unit 105 in the navigation device 100. However, only the part necessary for route search and map display is stored in the server each time. It is good also as what is acquired from 200.
The route search unit 107 searches for a route with reference to the map database.
The display control unit 106 displays the map and the searched route on the display of the navigation device 100 using the map database storage unit 105.

B. data structure:
FIG. 3 is an explanatory diagram showing the structure of the map database. An overview of information stored in feature data, character data, and network data is shown.

B1. Network data:
Network data is data representing roads as links and nodes. In this embodiment, two types of network data, main network data and semi-network data, are prepared. In the figure, links L1 to L4 and nodes N1 and N2 indicated by solid lines are main network data, and links L11 to L13 and nodes N11 and N12 indicated by broken lines are semi-network data.
Both main network data and semi-network data store link data and node data belonging to each. The link data records the coordinates of the point sequence forming each link, the type of national road / prefectural road, the number of lanes, other attribute information, and traffic regulation information. The node data records coordinate values, traffic restrictions, and the like.
However, the main network data is data whose traffic regulations have been sufficiently established by field surveys, and can be used without any trouble for vehicle route search. On the other hand, the quasi-network data is data that cannot be said to have sufficient traffic regulations, and is preferably not used in the vehicle route search. Also in this embodiment, the route search is basically performed using the main network data.

B2. Character data:
The character data 212 is data defining a character for displaying a feature name or a place name. In the figure, an example of data for displaying the name of the building BLD is shown. Character data stores information such as contents, position, feature, font, size, and the like.
The content is a character string to be displayed, and in the example in the figure, is the company name “ΔΔ (stock)”.
The position is a position where a character is displayed. In this embodiment, the coordinate value is designated with the lower left point P5 of the character string as a reference point.
The feature is a polygon name of the feature data with which the character is associated.
The font and size are designation of the font and size for display.
In addition, various attributes such as color and bold may be specified.

B3. Feature data:
The structure of the feature data 211 is shown by taking the building H1 as an example. The feature data 211 is polygon data for drawing features such as buildings and roads, and stores names, shapes, representative points, doorway lines, arrival points, attributes, and the like.
The name is the name of the feature. An ID unique to the polygon may be used.
The shape is a sequence of coordinates indicating the vertexes of the polygon of the feature. In the illustrated example, the coordinates of the vertices P1, P2, P3, and P4 of the polygon of the building H1 are stored.
The representative point is the coordinates of the point C that represents the position of the feature. The representative point often uses the centroid of the feature, but can be set arbitrarily.
The entrance / exit line is information for associating a feature with a road. In the case of the building H1, a line segment D for exiting from the entrance to the road is registered as an entrance / exit line. Specifically, the coordinates of both ends of the line segment D are registered. As for the entrance / exit line, only the end point on the road among the line segment D may be registered. In addition, the entrance / exit line is set for a feature such as a building or a parking lot, and it is not necessary to set it for all the features. In the example in the figure, the entrance / exit line DB1 on the front side for the building BLD, the entrance / exit line DB2 on the parking lot BLDP side, the entrance / exit lines DH2 to DH4 for the buildings H2 to H4, and the entrance / exit line DPK for the parking lot PK are set. Has been.

The arrival point G is a point on the network that can be reached from an end point on the road of the feature entry / exit line via any road. In the case of the building H1, the arrival point G is set on the link L2 because it can reach the link L2 via the road R21 associated with the entrance / exit line D as indicated by the dotted line in the drawing. It is also possible to follow the road R21 from the entrance / exit line D in the right direction in the figure, turn right at the node N11 and take a route to the node N2, and use the node N2 as an arrival point. In the present embodiment, since the route from the building H1 to the node N2 is shorter than the route from the building H1 to the node N2, the setting is made in this way. Since the arrival point need not be limited to one, the node N2 may also be set as the arrival point.
In the example of the figure, the arrival point for the buildings H2 to H4 is set as a point GH. For the building BLD, the points GH and GBLD2 are set. The arrival point can be set in the parking lot as well as the entrance / exit line, and in the example shown in the figure, the arrival point GPK is set for the parking lot PK. Since the parking lot PK faces the link L2, the end point of the entrance / exit line DPK and the arrival point GPK coincide with each other.

B4. Setting the arrival point:
FIG. 4 is an explanatory diagram showing setting of arrival points. The arrival point for the entrance / exit line DB of the building BLD1 is shown.
As main network data around the building BLD1, there are a link L7, a node N7, links L5 and L6, and nodes N5 and N6. As the quasi-network data, there is a link L14 indicated by a broken line.
The route reaching the main network from the entrance / exit line DB of the building BLD1 via one of the roads includes three types shown by dotted lines in the figure. The route reaches the link L7 via the road R24, and the route reaches the link L6 and the link L5 via the road R25. The points where these routes reach links L7, L6, and L5 are arrival points G7, G6, and G5.

These arrival points can be obtained by route search. In this embodiment, each feature is associated with one of the roads by an entry / exit line, so the arrival point may be obtained by route search starting from the entry / exit point, that is, the end point on the road of the entry / exit line. .
This route search may use all of the main network data, quasi-network data, and road polygons. Road polygons are not composed of links and nodes, but because there is data specifying adjacent polygons, the relationship between polygons is defined, and as with links and nodes, routes It can be used for searching. As a result of the route search starting from the entrance / exit point, a point where the main network data is reached may be set as the arrival point.

When three arrival points G7, G6, and G5 are found as in the example of the figure, these three points may be used as the arrival point of the building BLD1, for example, the point where the road from the feature is the shortest , Even if you select by the criteria such as the point with the shortest distance from the feature, the point where there is a lot of overlap between the route from the feature to the arrival point and the quasi-network data, or the point close to the direction from the feature to the departure point Good.
In the example shown in the figure, if the route or distance from the feature is selected as a reference, the point G5 closest to the building BLD1 is the arrival point. If an overlapping portion with the quasi-network data is selected as a reference, the point G6 becomes the arrival point. If the departure point is in the leftmost direction in the figure, the point G7 becomes the arrival point if the direction of the departure point is selected as a reference.

  In this embodiment, the arrival point is set according to the above-described procedure, and is set in advance in the feature data 211. The arrival point may not be set in advance, but may be obtained in the course of processing such as route search.

C. Route search process:
FIG. 5 is a flowchart of the route search process (1). This is a process mainly executed by the route search unit 107 of the navigation device 100, and is a process executed by a CPU of the navigation device 100 (hereinafter simply referred to as “CPU”) in terms of hardware.

In this process, the CPU inputs a departure place and a destination (step S10). The departure point may be specified by the user, or the current position acquired by GPS or the like may be set as the departure point.
As the destination, a feature may be designated, or a coordinate value may be designated.

The CPU acquires an arrival point for the designated destination (step S11). When a destination feature is designated, the arrival point may be read from the feature data corresponding to the designated feature. When the destination is designated by coordinates, it is only necessary to identify which polygon the coordinates are included in and to read the arrival point corresponding to the feature data of the identified polygon.
If the arrival point is not stored in advance in the feature data, the route search described in FIG. 4 may be performed to obtain the arrival point.

Next, the CPU performs a route search starting from the arrival point and searches for a parking lot (step S12). This parking lot is a point used for a route search to be described later as an alternative destination.
An example of searching for a parking lot is shown on the right side of the figure. It is assumed that an arrival point GH0 located at a position via the road R03 with respect to the destination H0 designated by the user is set. When performing the route search starting from the arrival point GH0, the CPU can search the parking lot PK2 that follows the link L02 upward and the parking lot PK1 that follows the link L02 downward and the parking lot PK1 that follows the link L00. The search range is regulated by conditions such as being within a predetermined distance from the destination H0 and being within a predetermined route from the arrival point GH0.
The reason why the respective parking lots can be found in the search is that the arrival points GPK1 and GPK2 are set on the links of the main network for the parking lots PK1 and PK2, respectively. By setting the arrival point in this way, the CPU can specify that the entrances and exits of the parking lots PK1 and PK2 are opened to the links L00 and L02, respectively, and extract these parking lots as search results. Can do it.

The CPU selects a parking lot having the shortest journey from the arrival point among the parking lots searched in this way (step S13). In the example in the figure, the parking lot PK2 close to the arrival point GH0 is selected.
Then, a route search is performed using the selected parking lot PK2 as an alternative destination (step S14), and a route from the departure point to the arrival point GPK2 of the parking lot PK2 and a route from the parking lot GPK2 to the arrival point GH0 are output. (Step S15). Furthermore, a route from the arrival point GH0 to the destination H0 may be output.

  FIG. 6 is a flowchart of the route search process (2). Similar to the processing described with reference to FIG. 5, the CPU inputs a departure point and a destination (step S10), and acquires an arrival point for the destination (step S11).

Then, the CPU searches for a parking lot by a route search starting from the arrival point (step S12a). Here, the search is performed using not only main network data but also quasi-network data and road polygon data.
A search example is shown on the right side of the figure. The main network data is the links L00 and L01 and the node N indicated by solid lines. The quasi-network data is L02a indicated by a broken line. The arrival point for the destination H0 is a point GH0a that reaches the main network via the road R03 and the link L02a of the semi-network data (matches the node N).
When a route search starting from the arrival point GH0a is performed, the CPU follows the link L00 to find the parking lot PK1. Further, in order to utilize the semi-network data, the parking lot PK2 is found by following the link L02a. The search range may be restricted by the distance from the destination or the like, as described with reference to FIG.

  When the parking lots PK1, PK2 are found in this way, the CPU selects a parking lot where the route from the arrival point and the route from the destination to the arrival point overlap (step S13a). In the example of the figure, the route from the destination to the arrival point is a route passing through the road R03 and the link L02a as indicated by the dotted line in the figure. Since the route from the arrival point to the parking lot PK1 is a left arrow along the link L00, it does not overlap with the dotted route described above. On the other hand, since the route from the arrival point to the parking lot PK2 is an upward arrow route along the link L02a, it overlaps with the above-described dotted line route. Therefore, in the example shown in the figure, the parking lot PK2 is selected.

  When the parking lot is selected in this way, the CPU searches for the route using the selected parking lot as the destination (step S14), and finds the route from the departure location to the parking lot PK2 and the route from the parking lot PK2 to the arrival point. Output (step S15a). In this processing example, when these two routes partially overlap, the overlapping portion of the route from the parking lot PK2 to the arrival point may be deleted and displayed. In this way, unnecessary large turns can be avoided.

  The process of selecting a parking lot (step S13 in FIG. 5 and step S13a in FIG. 6) may be applied in accordance with both criteria. For example, in step S13a of FIG. 6, when a process for selecting a parking lot with overlapping routes is performed, and this process does not determine one parking lot, that is, when a plurality of parking lots are selected in this process. If no parking lot is selected, a parking lot with the shortest path may be selected from the remaining parking lots (step S13 in FIG. 5).

Further, in the route search of the parking lot, it is also possible to set the arrival point as a point that reaches the quasi network from the destination H0 in accordance with using the quasi network. In the example of FIG. 6, the point GH1a where the road R03 intersects the quasi-link L02a is the arrival point. Although the parking lots PK1 and PK2 can also be found by route search based on this point, the parking lot PK2 that is the shortest route is selected.
However, in this case, it is necessary to use the quasi-network in the route search from the departure point to the arrival point GH1a. In order to avoid such a situation, both the arrival point GH1a for searching for an alternative destination such as a parking lot and the arrival point GH0a used when searching for a route from the departure point are set for the building H0. You may do it.

D. Route Search Example According to the processing of the present embodiment, as shown in FIGS. 5 and 6, by searching for a parking lot that should be an alternative destination by route search starting from the arrival point for the destination H0, the river It is possible to select a convenient parking lot PK2 instead of the inconvenient parking lot PK1 across the RV.
Hereinafter, another example in which a highly convenient parking lot is selected according to the present embodiment will be described.

FIG. 7 is an explanatory diagram of an alternative destination search example (1). Consider a case where a destination H7 in the figure is designated. The arrival point is set at a point G7 that reaches the link L71 via the road R70.
If the conventional technique is used, a parking lot is searched by a route search starting from the node N71 located at the shortest distance D7 from the destination H7. Therefore, a route search along the link L73 is performed as indicated by an arrow P72. The parking lot PK72 is selected.
On the other hand, according to the embodiment, since the route search is performed with the arrival point G7 as the starting point, the route search is performed along the link L71 as shown by the arrow P71, and the parking lot PK71 is selected.
In the embodiment, as a result of the route search starting from the arrival point G7, the parking lot PK2 may be found, but the parking lot PK71 having the shortest path from the arrival point is selected ( (See step S13 in FIG. 5).

FIG. 8 is an explanatory diagram showing an alternative destination search example (2). Consider a case where a destination H8 in the figure is designated. The arrival point is set to a point G8 (which coincides with the node N82) that reaches the link L81 via the road R80. The road R83 near the destination is a three-dimensional intersection that passes under the road R80.
If the conventional technique is used, a parking lot is searched by a route search starting from the node N81 located at the shortest distance D8 from the destination H8, and therefore, along the links L83 and L82 as indicated by arrows P81 and 82. A route search is performed and the parking lot PK82 is selected.
On the other hand, according to the embodiment, in order to search for a route starting from the arrival point G8, a route search is performed along the link L81 as shown by the arrow P83, and the parking lot PK81 is selected.
In the embodiment, as a result of the route search starting from the arrival point G8, the parking lot PK82 may be found, but the parking lot PK81 having the shortest path from the arrival point is selected ( (See step S13 in FIG. 5).

As shown in these examples, according to this embodiment, it is possible to select a convenient parking lot reflecting the state of the road around the destination.
In the above embodiment, an example in which the alternative destination is a parking lot has been described. However, the present invention can also be applied to a case where an alternative destination other than the parking lot is used. For example, if you want to stop at a store around the destination and then go to the destination, the store may be used as an alternative destination. In this embodiment, a process for searching for a designated store may be performed instead of the process for searching for a parking lot. Whether each feature corresponds to the designated store can be determined by referring to the attribute of the feature data. In addition, what kind of store is used as an alternative destination may be specified when the user performs a route search, or may be set in advance.
By doing this, even if the user is unfamiliar with the geography of the vicinity of the destination, the user can know the route to a convenient place to go to the destination by specifying the attribute of the alternative destination.

The present invention does not necessarily have all the functions of the above-described embodiments, and only a part may be realized. Moreover, you may provide an additional function in the content mentioned above.
Needless to say, the present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the spirit of the present invention. For example, a part configured in hardware in the embodiment can be configured in software and vice versa.

The present invention can also be configured as a route search method described below.
Up to alternative destinations that can be used when heading to a destination specified by a computer system having network data representing roads as nodes and links, and feature data storing polygons for drawing features including roads A route search method for searching for a route,
An input step for inputting the designation of the starting point and destination and storing them in a memory;
Referring to the map database, points on the road where the network data is maintained as roads through which automobiles can pass, and can be reached from any feature corresponding to the destination through any road An arrival point acquisition step of acquiring an arrival point that is and storing information representing the arrival point in a memory;
By referring to the network data, an alternative destination having a predetermined attribute reachable from the arrival point is searched by a route search starting from the arrival point, and information representing the alternative destination is stored in a memory. An alternative destination search step;
A route search method comprising: a route search step of searching for a route from the departure point to the searched alternative destination with reference to the network data.

Furthermore, you may comprise as a computer program shown below.
Up to alternative destinations that can be used when heading to a destination specified by a computer system having network data representing roads as nodes and links, and feature data storing polygons for drawing features including roads A computer program for searching for a route,
An input function for inputting the designation of the starting point and destination and storing them in the memory;
Referring to the map database, points on the road where the network data is maintained as roads through which automobiles can pass, and can be reached from any feature corresponding to the destination through any road An arrival point acquisition function for acquiring an arrival point that is and storing information representing the arrival point in a memory;
By referring to the network data, an alternative destination having a predetermined attribute reachable from the arrival point is searched by a route search starting from the arrival point, and information representing the alternative destination is stored in a memory. Alternative destination search function,
A computer program for causing a computer to implement a route search function for searching for a route from the departure point to the searched alternative destination with reference to the network data.

  The present invention can be used to guide a route to a highly convenient alternative destination when a destination is designated.

DESCRIPTION OF SYMBOLS 100 ... Navigation apparatus 101 ... Main control part 102 ... Transmission / reception part 103 ... Command input part 104 ... GPS input part 105 ... Map database memory | storage part 106 ... Display control part 107 ... Path | route search part 200 ... Server 201 ... Transmission / reception part 202 ... Database management Unit 210 ... Map database storage unit 211 ... Feature data 212 ... Character data 213 ... Network data

Claims (4)

A route search system that searches for a route to an alternative destination that can be used when traveling to a specified destination,
A map database storage unit for storing network data representing roads as nodes and links, and feature data for storing polygons for drawing features including roads;
An input part for inputting the designation of the starting point and destination;
Referring to the network data and feature data, it is a point on the road where the network data is maintained as a road on which a car can pass, and passes through any road from the feature corresponding to the destination. An arrival point acquisition unit for acquiring an arrival point that can be
An alternative destination search unit that refers to the network data and searches for an alternative destination having a predetermined attribute that can be reached from the arrival point by route search starting from the arrival point;
A route search system comprising: a route search unit that performs a route search from the departure point to the searched alternative destination with reference to the network data. The route search system according to claim 1,
The route search system is a route search system that preferentially searches for an alternative destination having a short distance from the arrival point to the alternative destination when a plurality of alternative destinations are searched. The route search system according to claim 1 or 2,
The route search unit, when a plurality of alternative destinations are searched, an alternative destination where a route from the arrival point to the alternative destination partially or entirely overlaps with a route from the destination to the arrival point Route search system that performs route search with priority. A route search system according to any one of claims 1 to 3,
The alternative destination search unit is a route search system that searches for the alternative destination by route search using road polygon data included in the feature data in addition to the network data.

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