JP5491919B2 - Guidance system - Google Patents

Description

  The present invention relates to a guidance system for guiding a designated 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. In the navigation system, it is preferable that the user who has reached the vicinity of the destination visually recognizes the building or the like and realizes guidance that can be sure that the destination is the destination. As one method for realizing such guidance, it is conceivable to show the user the characteristics of a building or the like as a destination, such as “a house with a red roof”.

Patent Document 1 discloses a technique used for guidance after evaluating a guide mark at an intersection based on a distance between the mark and the intersection, a discovery distance, a uniqueness, and the like.
Patent Document 2 discloses a technique for performing guidance using landmarks, and refers to attributes attached to landmarks such as good visibility both day and night, whether during daytime driving or during night driving. A landmark to be used for guidance is selected according to driving conditions.
Patent Document 3 discloses a technique for selecting a mark in the vicinity of an intersection such as a school, a post office, a gas station, etc., and presenting this mark for guidance.
Patent Document 4 discloses a technique for providing guidance indicating the characteristics of the destination building itself, such as “Two-story on the right side, arrived at the destination” when arriving at the destination in addition to route guidance. doing.

JP-A-7-63571 JP-A-7-98800 JP-A-9-292260 Japanese Patent Laid-Open No. 10-9886

In the prior art, landmarks such as landmarks that can be easily understood by the driver are used for guidance. However, the destination selected by the user is not necessarily limited to the place where the mark suitable for guidance exists in the vicinity. Also, depending on the landmark used for guidance, such as a gas station, a number of features corresponding to the landmark are found before reaching the destination, which may confuse the user.
Patent Document 4 discloses a technique for guiding not only a special landmark but also a feature of a destination building itself. However, for example, there is “right two stories” h. Since there are many buildings that fall under the feature of “h”, it was not possible to provide useful guidance. In order to be able to identify the guided building, it is only necessary to describe many features such as “red roof and white walls…”, but even if too many features are described, it falls under that feature Finding a building is very difficult.

In this way, depending on the location where the user travels, it is necessary to use features that cannot be called special landmarks, such as ordinary private houses and buildings, for the purpose of guidance. It was not possible to give accurate information that could be used to uniquely identify the mark. Such a problem is common not only when guiding the destination of a route but also when guiding various points along the route, such as an intersection that turns right and left.
In view of such problems, an object of the present invention is to provide information that allows a user to uniquely determine a guided landmark when guiding a predetermined guidance point on a route without excess or deficiency.

  The present invention can be configured as a guidance system. The guidance system guides a mark or the like so that the designated point can be discriminated on the spot when the user designates a destination or an intermediate point. Further, in combination with the route search, a point may be set after automatically setting points to be guided to the user (hereinafter referred to as guide points) such as a point to turn right or left in the route or a destination.

The guidance system of the present invention includes a map database recording unit, a current position acquisition unit, a guidance information setting unit, and a guidance unit.
The map database storage unit stores guide data for storing a combination of feature elements structured to represent the position of the guide mark that can serve as a mark when guiding a predetermined guide point on the route and the feature. Yes. For example, when a building is used as a guide mark, the feature of each building is expressed by dividing it into feature elements such as a roof color, a wall color, and a floor number. The guidance point may be specified by the user as described above, or may be automatically set by the guidance system. The destination itself can also be included in the guide point.
The current position acquisition unit acquires position information regarding the current position. For example, GPS (Global Positioning System) can be used.

  The guidance information setting unit first sets a predetermined range (hereinafter referred to as “marker search range”) for extracting a guide mark based on the guide point and the current position, and extracts a guide mark within this range. The guide mark can be extracted with reference to the guide data. The mark search range preferably includes a range from the front of the current position to the guide point, but may include a range further ahead of the guide point. Moreover, it is not necessarily limited to the range in which the guide mark is visible from the current position. For example, when there is a guide mark at the point of turning left or right at the intersection, it is also useful to guide the guide mark before turning right or left as in “XX seen after turning the intersection”.

  The guide information setting unit refers to the guide data, compares the structured feature elements, and provides a guide mark that can uniquely specify the guide point, and 1 or 2 that is necessary for uniquely specifying the guide point. The above feature elements are set. That is, it is determined which guidance mark is used and which characteristic element is presented so that the user can uniquely determine the guidance mark at the site. For example, when a building with a red roof and a white wall is used as a guide mark, if there is no building with a red roof around it, only the characteristic element “red roof” can be used. On the other hand, when there is a building with a red roof around it, two feature elements can be used in combination, such as “a white wall with a red roof”. In this way, the characteristic elements or combinations thereof are determined so that the guide landmarks can be uniquely identified.

  And a guidance part guides a guidance point by presenting the feature element about a guidance mark, and the positional relationship between a guidance mark and a guidance point according to the setting of a guidance information setting part. The presentation of information may be displayed on a display or the like, or voice guidance may be provided.

  According to the guide system of the present invention, the feature elements of the guide mark are structured and stored in the guide data, and the feature elements to be used are determined so that the guide mark can be uniquely determined at the site. In this way, the guidance system of the present invention can present information that is not excessive or insufficient to the user and guide the guide mark.

The guidance system may be combined with route search.
In order to realize the route search, the map database storage unit further stores network data representing roads as nodes and links, and feature data 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 feature data may be integrated with the guidance data described above.
Then, the designation of the starting point and the destination is input. The user's current location may be used as the departure location. 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.
Although the route search from the departure point to the destination may be performed using the above-described network, the route search may be performed by providing an arrival point acquisition unit and a route search unit described below.
The arrival point acquisition unit refers to the network data and the feature data, is a point on the road where the network data is maintained as a road on which the car can pass, and any road from the feature corresponding to the destination Get the arrival point, which is the point you can arrive through.
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 only needs to 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 route search unit searches the route from the departure point to the arrival point with reference to the network data.
In the configuration combined with the route search, the guidance unit provides guidance by presenting the result of the route search according to the position information along with the guidance.

When applied in combination with the route search, guidance such as “destination at the intersection” can be provided based on the route traveled by the user, increasing usefulness.
Further, the above aspect is characterized in that even when a feature deviating from the main network is used as a destination, route search and route guidance can be performed by using the arrival point. In route guidance to a point outside the main network, there are few landmarks that can be called so-called landmarks, and there are often only landmarks that are common. Therefore, when such a route search is used, the present invention in which information that is not excessive or insufficient for specifying a guide mark is provided by a combination of feature elements is particularly useful.

  As described above, the route search unit may automatically set a guide point such as a point where the intersection turns right or left based on the result of the route search. This saves the user the trouble of setting a guide point, and also makes it possible to provide guidance using a guide mark at a point where the route is likely to be mistaken, thereby realizing easy-to-understand route guidance.

Since acquisition of the current position usually includes a predetermined error, it is preferable to consider such an error range when extracting a guide mark or the like. The current position error is a value determined according to the configuration of the current position acquisition unit. It is not always necessary to measure a strict error, and a value set as an approximate error range may be used.
For example, the predetermined range for extracting the guide mark, that is, the mark search range may be set based on the forefront position of the current position obtained in consideration of the error in the current position acquisition unit.
Guidance landmarks are useful for guidance only in front of the user. Thus, if it sets based on the forefront position, a useful guide mark can be extracted.
In the aspect combined with the route search, since the route that the user travels is known, the landmark search range may be set forward along the route from the above-mentioned foremost position. The forefront position may be included, or may be set with a margin further ahead of the forefront position in accordance with the traveling speed of the user.
In an aspect not combined with route search, the landmark search range can be set based on the line segment connecting the forefront position and the guide point. For example, a range in which the line segment has a predetermined width can be used as the landmark search range.

On the other hand, the error of the current position can also be taken into account for the evaluation of the guide mark.
For example, the guidance information setting unit targets a range from the last position of the current position to the guidance point obtained in consideration of errors in the current position acquisition unit (hereinafter referred to as “marking evaluation range”). It may be determined whether or not can be uniquely identified. If there is another building or the like having the same characteristics as the guide mark in front of the user, the guide mark cannot be uniquely identified, and the guide point cannot be specified. When the landmark evaluation range is set with the acquired current position as a reference, if the actual current position is behind the acquired current position due to the effect of error, it is guided to a building that is not included in the landmark evaluation range. There is a possibility that there is a building with the same characteristics as the landmark. On the other hand, if the mark evaluation range is set with reference to the rearmost position of the current position in consideration of errors, the possibility that a building having the same characteristics as the guide mark exists in the traveling direction of the actual user is reduced. This makes it possible to provide useful guidance.

In the present invention, various methods can be used to evaluate the usefulness of the guide mark. For example, an evaluation value representing usefulness as a mark may be stored for each feature element in the guidance data. When there are a plurality of uniquely identifiable guide marks, the guide information setting unit can set the guide marks used for the guide and the characteristic elements thereof by evaluating the usefulness using the evaluation values.
As an example of the evaluation method, a method of extracting a feature element that can uniquely identify a guide point from the feature element attached to the guide mark and evaluating it with the evaluation value attached to the extracted feature element. It may be taken. When combining multiple feature elements to uniquely identify a guide point, the maximum value of evaluation values assigned to each feature element or a predetermined arithmetic expression using these evaluation values Evaluation can be made.
From the viewpoint that the user can easily understand the guide mark, it is preferable that fewer feature elements are presented. In consideration of this point, when the feature elements are used in combination, the evaluation value may be lowered as compared with the case where the feature elements are used alone.

  When the guidance point can be uniquely specified by a combination of two or more guidance landmarks, the guidance information setting unit may use the combination for guidance. The combination of guide marks refers to a guide using two or more guide marks, such as “front of building A, left side of building B”. By making such a combination available, it is possible to guide a destination even when a guide point cannot be specified with a single guide mark.

Guidance that combines two or more guidance landmarks may be more difficult to understand than guidance that uses a single guidance landmark.
From this point of view, the guidance information setting unit is used for guidance after evaluating the usefulness of the feature elements of each guidance element as the number of guidance landmarks necessary for uniquely identifying the guidance point increases. A guide mark or a combination thereof may be set. In other words, when using a single guide mark, such as “the front of a house with a red roof”, and using two guide marks, “the front of a house with a red roof, the left side of a house with a white wall” In the case of guiding in this way, the latter lowers the evaluation value given to the characteristic elements “red roof” and “white wall”. By doing so, priority can be given to a guidance method that uses few guide marks, and guidance that is easy for the user to understand can be realized.

  In addition, the present invention may be configured as a route guidance method using a computer, or may be configured as a computer program for causing a computer to execute such route guidance. 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 structure of a guidance 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 explanatory drawing which shows the structure of guidance data. It is a flowchart of a guidance process. It is explanatory drawing which shows the setting method of a mark search range and a mark evaluation range. It is a flowchart of a mark guidance process. It is explanatory drawing which shows the evaluation method of a mark. It is a flowchart of a marker candidate extraction process.

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. Setting the arrival point:
B5. Guidance data:
C. Guidance process:
D. Placemark guide processing:
D1. Setting of placemark search range:
D2. Contents of placemark guidance processing:
D3. Evaluation of placemark:
D4. Marker candidate extraction processing:

A. System configuration:
FIG. 1 is an explanatory diagram showing the configuration of the guidance system. The guidance 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, network data 213, and guide data 214.
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 guidance data 214 is data used for guiding the guide mark to the user at the time of route guidance, and is data representing the characteristics of the guide mark in a structured manner. These data structures will be described later.
The guide data 214 and the feature data 211 can be integrated, but in this embodiment, they are provided separately.

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 position information 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 stored in the map database storage unit 210 included in the server 200 is also stored in the map database storage unit 105 in the navigation device 100, but is necessary for route search and map display. It is good also as what acquires only the part which becomes from the server 200 each time.
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.
The guidance control unit 108 realizes guidance using a guidance mark so that the user can determine the destination at the site.

B. data structure:
FIG. 2 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, entrance / exit 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. 3 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.

B5. Guidance data:
FIG. 4 is an explanatory diagram showing the structure of guidance data. The guidance data is data used to provide a guide mark so that the user can determine the destination at the time of route guidance. In the guidance data, features of a building or the like that can serve as a guide landmark are structured and stored by a plurality of feature elements. It is not necessary to prepare the guidance data for all the features included in the feature data. It is only necessary to prepare the guidance data for the features that can be structured and describe the features. From this point of view, in this embodiment, the guidance data is separate from the feature data. However, since the feature data is targeted, the integrated data is obtained by incorporating a feature element into a part of the attribute of the feature data. It is also possible to construct.

In the figure, the guide data of the buildings H41 to H43 are illustrated. The guidance data stores information such as name, position, type, floor number, wall, roof, solar, and roof shape. The contents will be described taking the building H41 as an example.
The name is a name given to the building and is an index associated with the feature data.
The position is the position coordinate (latitude, longitude) of the building H41.
The type is the type of the building H41. In this example, it is “private house”, but it may be a more subdivided type such as “Western style private house”.
The number of floors indicates that the building H41 is two stories. It is good also as the content showing the external appearance structure of a building in detail like "total 2 floors".
The wall represents the color and structure of the wall of the building H41. In this example, it is described by a combination of (brick, 50, *). This indicates that the color is brick color or brick, the evaluation value is 50 points, and “*” indicates that there is no restriction on the direction in which the feature can be visually recognized. The evaluation value is an index representing the effectiveness when the feature element is used for guidance, and can also be referred to as an index representing how conspicuous the feature element is. The evaluation value can be arbitrarily set in consideration of such a psychological influence. You may prepare a list that gives evaluation values for the wall color in advance and give a unified evaluation value, but how much it stands out depends on the size, material, and vividness of the wall Since it is also influenced by the surrounding environment, it is preferable to set based on a sensory test by several investigators.
In the example shown in the figure, the wall color is only a single color. However, it may be possible to express a two-ton color such as “first floor: brown, second floor: cream”. Further, data corresponding to the direction such as (red, 50, south), (brown, 30, east-west north) may be held. This example shows that the south side is red and the other directions are brown.
The roof is the color of the roof. Described in the same combination as the wall. In other words, (green, 50, *) indicates that there is no limit on the green roof, the evaluation value of 50 points, and the direction in which it can be visually recognized.
Solar represents the installation of facilities such as solar power or solar water heaters. (None, 0, *) indicates that these facilities are not installed, have an evaluation value of 0 points, and are not installed, and thus cannot be viewed from any direction.
The roof shape is a roof shape. (Triangle, 30, *) represents a triangular roof like a so-called pointed hat, an evaluation value of 30 points, and no restriction on visibility. Although the shape of the roof is easy to use as a characteristic element of the landmark, it is not only relatively easy to understand, such as a wing, gable, flat, etc. You may make it also provide the image data which can show a shape to a user with an illustration etc. collectively.
The guide data records various features in this way. In the example in the figure, no evaluation value is provided for the floor number, but it can be prepared in the form of (number of floors, evaluation value, visible orientation) as with other features.

The building H42 is an example of a two-story Japanese style private house, and records the same characteristic elements as the building H41. Although the type is “private house”, it may be described as “Japanese style private house”.
Building H43 is an example of a three-story modern-style private house. Since the roof shape is flat and the color of the roof is difficult to see from the road, the evaluation value for the roof is set to 0 points such as (white, 0, *). Moreover, since the building H43 has a bay window and a balcony, data was recorded as a characteristic element for these.

The guide data is data in which the characteristic elements are described for each guide mark as described above, but the description of the data itself can take various forms.
For example, the guidance data may be a so-called table type database. In this case, for buildings H41 and H42, it is necessary to prepare data (no balcony, 0, *) for items such as bay windows and balconies (indicating that there is no balcony and the evaluation value is 0 points). Although not useful, there is an advantage that a unified structure can be achieved for the guide mark.
The guide data may be in a data format using a markup language such as HTML or XML. That is, it is possible to take a form in which the content elements are specified after identifying the characteristic elements such as “roof” and “wall” by the tags. By doing so, it is not necessary to prepare data for the building elements H41 and H42, such as bay windows and balconies, which are not useful for evaluation of guide landmarks, and the data capacity can be reduced. It becomes. In addition, when a new feature element that is not initially planned is generated (for example, when a building having a “weathercock” is newly found), there is an advantage that the feature element can be flexibly added.

C. Guidance process:
FIG. 5 is a flowchart of the guidance process. This is a process mainly executed by the route search unit 107, the guidance control unit 108, and the display control unit 106 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. is there.

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. 3 may be performed to obtain the arrival point.
Next, the CPU searches for a route from the departure place to the arrival point (step S12). Further, a route from the arrival point to the destination may be output.

When the route is obtained in this way, the CPU executes route guidance.
Position information is input by GPS or the like (step S20), and a route guidance process is performed (step S21). The route guidance process is a process for displaying the searched route and the current position on the display of the navigation device 100. In addition, voice guidance may be provided.
Then, the CPU performs a landmark guidance process (step S100). The landmark guidance process is a process of performing guidance that presents a landmark to the user so that the user can identify a building or the like as a destination on site. Details of the processing will be described later. In the present embodiment, an example in which the landmark guide process is performed on the destination is shown, but this process may be performed on a guide point such as an intersection that turns right or left on the route. In addition to the destination, the guide point where the guide guidance process should be performed may be set by the user specifying each point on the route, or by automatically extracting and setting an intersection that turns right and left. Moreover, even if it is a part that goes straight, it can be added to the guide point in order to make the user sure that the route in progress is correct.
The CPU repeatedly executes the above processing (steps S20 to S100) until it arrives at the destination (step S200).

D. Placemark guide processing:
D1. Setting of placemark search range:
FIG. 6 is an explanatory diagram showing a method for setting the landmark search range and the landmark evaluation range. The landmark search range and the landmark evaluation range are ranges set in the landmark guidance process. For convenience of explanation, a method for setting these ranges will be described prior to the processing contents.
First, it is assumed that the current position PP of the vehicle is obtained by GPS. The GPS includes a predetermined detection error depending on a code to be used, a radio wave reception condition, and the like. It is assumed that this detection error is an error EP1 in the forward direction and an error EP2 in the backward direction. As a result of including the error, the current position of the vehicle is estimated to be between the foremost position PP1 and the rearmost position PP2. A range from the foremost position PP1 to the rearmost position PP2 is referred to as a self-position estimation range.
The error in the current position varies depending on devices such as GPS, and fluctuates depending on the reception status of radio waves even while traveling. However, the self-position estimation range does not need to accurately reflect these errors. This is because, as will be described later, the self-position estimation range is used as a reference for extracting a feature as a landmark and its evaluation. However, it is not preferable that the current position of the vehicle deviates from the self-position estimation range. Therefore, the self-position estimation range is preferably set based on the estimated maximum error. This error can be arbitrarily set based on specifications such as GPS.

It is assumed that the features LM1 to LM4 serving as landmarks exist beside the road RD on which the user travels. The feature LM1 is positioned ahead of the destination DEST, and the features LM2 to LM4 are positioned in front.
The landmark search range, that is, the range in which the landmark feature is searched is set based on the current position of the vehicle and the position of the destination DEST. In the present embodiment, the destination search range is set from the foremost position PP1 of the vehicle to the position of the distance L1 beyond the destination DEST. The range represented by the distances L1 and L2 in the figure is the landmark search range. The mark within the mark search range is used for guidance.
The reason why the landmark search range is set in this way will be described. If the landmark search range is set ahead of the rearmost position PP2, the feature LM4 may be extracted as a landmark. However, the current position may be the forefront position PP1. In the forefront position PP1, the feature LM4 cannot already be a valid mark because it has already passed the feature LM4. In this embodiment, the landmark search range is set based on the foremost position PP1 in order to suppress the possibility of such a trouble. In this way, if the landmark search range is set in the range of the distances L1 and L2 in the figure, no matter where the current position of the vehicle is in the self-position estimation range (the range of PP1 to PP2), it is ahead of it. Since there is a mark on the, effective guidance can be performed.

  The distances L1 and L3 for determining the landmark search range can be arbitrarily set. It is preferable to set the mark in a visible range. In addition, when the traveling speed of the vehicle is high, it is preferable to guide the vehicle early, so that the distance L3 may be increased as the traveling speed increases.

Whether or not the landmark extracted from the landmark search range can uniquely specify the destination DEST is evaluated based on whether or not there is a similar landmark within a predetermined range in the vicinity. The range in which this evaluation is performed is the mark evaluation range. In this embodiment, the mark evaluation range is set at a position ahead of the rearmost position PP2. A range surrounded by a broken line in the mark diagram is a mark evaluation range ALM. The forefront is the same as the forefront of the landmark search range (position at a distance L1 from the destination).
The reason for this setting will be described. If the landmark evaluation range is set in front of the foremost position PP1, that is, the same as the landmark search range, the features LM3 and LM4 are not considered in the evaluation of whether or not the destination can be uniquely identified. Become. In such a state, even if the extracted landmark, for example, the feature LM1 or LM2 has the same characteristics as the features LM3 and LM4, it is determined that the destination can be uniquely specified. However, if the actual position of the vehicle is the rearmost position PP2, the user sees the features LM3 and LM4 having the same characteristics, and the destination DEST is uniquely determined by the guided landmark. It becomes impossible to identify. In this embodiment, in order to avoid such trouble, the mark evaluation range is set based on the rearmost position PP2.

  That the mark evaluation range is set based on the rearmost position PP2 means that the mark evaluation range is set in consideration of the self-position estimation accuracy. When the self-position estimation accuracy is high, the mark position evaluation range becomes narrow because the rearmost position PP2 moves forward according to the accuracy. Therefore, since it becomes easy to extract a mark and its features that can uniquely specify the destination, the processing period can be shortened, and the guidance content can be made simple and easy to understand. That is, according to the above aspect, it is possible to provide appropriate guidance information for preventing misunderstanding of the user according to the self-position estimation accuracy.

  In the present embodiment, guidance using a mark is performed based on the various ranges set above. The timing at which this guidance is performed is a range in which the foremost position PP1 of the vehicle is not less than a distance L3 and not more than a distance L3 + L4 from the destination DEST (the hatched range in the figure is hereinafter referred to as “guidance section”). It is time to enter. If guidance is performed in a state where the vehicle is too close to the destination DEST, the user may pass the destination DEST. Also, if guidance is provided while at a location far from the destination, the user may be confused without finding the landmark. The distances L3 and L4 can be arbitrarily set in consideration of these circumstances. The guidance section is also affected by the traveling speed of the vehicle. When the traveling speed is fast, it is preferable to increase both the distances L3 and L4. The distances L3 and L4 may be fixed values or values that change in accordance with the vehicle speed in this way.

D2. Contents of placemark guidance processing:
FIG. 7 is a flowchart of the landmark guidance process. This process corresponds to step S100 of the guidance process (FIG. 5).
In this process, the CPU first sets a self-position estimation range (step S102). The acquisition error (the errors EP1 and EP2 in FIG. 6 are reflected on the acquired current position, and the foremost position PP1 and the rearmost position PP2 are obtained.
Then, it is determined whether or not the foremost position PP2 of the vehicle is in the guidance section. First, it is determined whether distance L2 ≦ distance L3 (step S104). The distance L2 is a distance from the destination DEST to the forefront position PP1, and the distance L3 is a distance from the destination DEST to the forefront position of the guidance section.
In the case of distance L2 ≦ distance L3, it means that the vehicle is too close to the destination DEST, and thus the CPU performs short distance guidance (step S106). In the short distance guidance, a message indicating that the user has already arrived around the destination is displayed or voiced, such as “around the destination”. In addition, the current position of the vehicle and the map around the destination may be enlarged and displayed. In this case, considering that the current position of the vehicle includes an error, the map is preferably enlarged at a magnification that includes the vehicle's own position estimation range and the destination.
When the distances L3 and L4 are values that change in conjunction with the vehicle speed, the distance L2> distance L3 may occur when the user decreases the speed according to the short distance guidance. As shown in FIG. 5, the landmark guidance process (step S100 in FIG. 5) is a process that is repeatedly executed until the vehicle arrives at the destination. Therefore, as a result of the reduction in the vehicle speed, the distance L2> the distance L3 is changed. In this case, the determination in step S104 is changed to “NO”, the short distance guidance is ended, and guidance using a mark described later is performed.

  When distance L2> distance L3 (step S104), if distance L2 ≦ distance L3 + L4 is not satisfied (step S108), it means that the vehicle is in front of the guidance section. Accordingly, the CPU ends the process without performing any landmark guidance process.

If distance L2 ≦ distance L3 + L4 (step S108), it means that the foremost position PP1 of the vehicle is in the guidance section. Therefore, the CPU sets a landmark search range (step S110). As described with reference to FIG. 6, the mark search range is from the foremost position PP1 of the vehicle to the position of the distance L1 beyond the destination (range of distance L1 + L2 in FIG. 6).
Then, the CPU extracts landmark candidates from the landmark search range (step S120). That is, features belonging to the landmark search range are extracted from the features registered in the guidance data (see FIGS. 1 and 4), and the destination DEST can be uniquely specified in consideration of the feature elements. Choose things. Details of the processing will be described later.
The mark that can uniquely specify the destination DEST is not limited to one. Therefore, the CPU evaluates the features of the landmarks based on the evaluation points registered in the guide data.
The CPU determines a mark used for guidance based on the evaluation value of the mark candidate (step S140), and performs guidance using the mark (step S142). “The destination is the front of the house with a red roof”, and the determined landmark is explained with the characteristic elements and the positional relationship with the destination is shown. This guidance can be performed by display on the display and by voice.

D3. Evaluation of placemark:
FIG. 8 is an explanatory diagram showing a mark evaluation method. A specific example of the marker candidate extraction process (step S120 in FIG. 7) is shown.
In this example, let us consider a state in which houses H80 to H90 are arranged on both sides of the route traveled by the user as shown in the upper diagram. The destination DES8 is located between the houses H80 and H81. In the figure, houses H81, H82, H85, H87, H89, and H90 with roof and wall colors are houses registered in the guide data. Other houses are houses that are not registered in the guidance data but registered only in the feature data. The characteristics of the house are represented by various characteristic elements, but here, for the sake of simplicity, they are represented only by the color of the roof and the color of the wall.
Further, it is assumed that the mark search range and the mark evaluation range are the same.

  Next, three coefficients, a combination coefficient, a distance coefficient, and an eave number coefficient described in the table shown at the bottom of the figure will be described. These are coefficients used for obtaining the evaluation value of the entire mark based on the evaluation value of each feature element.

The combination coefficient is a coefficient for reducing the evaluation points as the number of feature elements used to represent one house increases. This is because, in order to express a mark, it is preferable that it is simply expressed with a small number of feature elements because it is easier to understand. The relationship between the feature element and the combination coefficient can be arbitrarily set, but is set as follows in this embodiment.
Number of feature elements 1, 2, 3, 4
Combination coefficient 1.0, 0.5, 0.3, 0.1

The distance coefficient is a coefficient for reducing the evaluation points as the distance from the destination DES8 to the landmark house increases. This is because it is preferable that the mark is closer to the destination DES8. The relationship between the distance and the distance coefficient can be arbitrarily set, but is set as follows in this embodiment.
Distance (eaves) 0, 1, 2, 3, 4
Distance coefficient 1.0, 0.9, 0.5, 0.3, 0.1
A distance of 0 means that the destination itself is used as a guide mark.

The number-of-eaves coefficient is a coefficient for reducing the evaluation points as the number of houses used as landmarks increases. In this embodiment, it is possible to use a mode of guiding with a combination of a plurality of houses, but in order to express a landmark, it is preferable in that it is easier to understand and find it easier to express with a small number of houses. Because. The relationship between the number of eaves and the number of eaves coefficient can be arbitrarily set, but in the present embodiment, it is set as follows.
Number of eaves 1, 2, 3, 4
Eaves factor 1.0, 0.5, 0.3, 0.1

Using these coefficients, the mark evaluation value is calculated by the following equation.
Evaluation value of mark 1 = (feature element 1 + feature element 2+...) × combination coefficient of mark 1 × distance coefficient of mark 1;
Evaluation value of mark 2 = (feature element 1 + feature element 2+...) × combination coefficient of mark 2 × distance coefficient of mark 2;
:
Overall evaluation value = (Evaluation value of mark 1 + Evaluation value of mark 2+...) × Number of eaves coefficient;
According to the above formula, first, after reflecting the coefficient according to the combination of the feature elements and the distance, the evaluation values of the feature elements are added to obtain the evaluation value for each mark. Then, the overall evaluation value is obtained by the procedure of adding the evaluation value for each mark and multiplying by the number of eaves coefficient.

Based on the lower table in the figure, the evaluation results using the above evaluation values and the like will be described. Since the landmark is preferably closer to the destination DES8, it is first evaluated whether or not the houses H81 and H82 closest to the destination DES8 are the landmarks.
Case 1 shows a case where the house H81 is used as a mark. The color of the wall (blue, with an evaluation value of 50 points) is used as the feature element. Since the feature elements are only the color of the wall, the number of feature elements is 1, so the combination coefficient is 1.0. Since the distance is next to one destination, the distance coefficient is 0.9. Since only the house H81 is used, the number of houses is one and the number of houses coefficient is 1.0. As a result, the evaluation value of case 1 is 45 (= evaluation value of wall color 50 × distance coefficient 0.9).
In the case 1, the destination is guided as “one house ahead of the house with a blue wall”, but the house corresponding to this is the house H84 in addition to the destination DES8. Therefore, in case 1, the destination DES8 cannot be uniquely guided and cannot be used as guidance.

Case 2 is a case where the color of the roof (green, with an evaluation value of 10 points) is used as a characteristic element of the house H81. In this case, the evaluation value is 9.
In Case 2, the destination is guided as “one house ahead of a house with a green roof”, but the destinations corresponding to this are destinations DES8, houses H84, H86, and H89. Therefore, the case 2 cannot be used for guidance.

  Similarly, Case 3 shows a case where the wall color (gray, with an evaluation value of 20 points) is used as a characteristic element of the house H82. Case 4 shows a case where the color of the roof (yellow, evaluation value 30 points) is used as a characteristic element of the house H82. None of these can be used as guidance because there are houses other than the destination DES8.

Case 5 is a case where two characteristic elements of the wall H and the roof color are combined for the house H81. Since two feature elements are used, the combination coefficient is 0.5. The distance coefficient and the number of eaves coefficient are the same as in cases 1 and 2. This evaluation value is 27 (= (10 + 50) × 0.5 × 0.9).
In Case 5, the destination is guided by specifying a landmark with two characteristic elements such as “one house in a house with a blue wall and a green roof”, but this applies to other destinations DES8. There is a house H84. Therefore, the case 5 cannot be used as a guide.
Case 6 is a case where two characteristic elements are similarly combined for the house H82. The case 6 is applicable to the destination DES8 as well as the house H86 and cannot be used as a guide.
As described above, it can be understood that the houses H81 and H82 cannot be used as landmarks only by using the houses H81 and H82 alone.

Next, a case where the houses H81 and H82 are used in combination will be considered.
Case 7 is a case where the characteristic element “blue wall” is used for the house H81 and the characteristic element “gray wall” is used for the house H82. For the houses H81 and H82, only one feature element is used, so that the combination coefficient is 1.0. Both distance coefficients are 0.9. Since this is a combination of two houses, the number of houses is 0.5. Therefore, the evaluation value is 31.5 (= (the evaluation value 45 of case 1 + the evaluation value 18 of case 3) × 0.5).
In case 7, the destination is guided by a combination of two houses, such as “one house ahead of the blue wall and the front of the house with the gray wall”. This applies only to the destination DES8. Therefore, the case 7 can be used as a guide. In the figure, a case that can be used as a guide is marked with a circle.

  Case 8 is an example in which the characteristic element “blue wall” is used for the house H81 and the characteristic element “yellow roof” is used for the house H82. The evaluation value calculated according to Case 7 is 36 (= (Evaluation value 45 of Case 1 + Evaluation value 27 of Case 4) × 0.5). Since only the destination DES8 exists, this can be used as a guide.

  Case 9 uses the feature element “green roof” for house H81, and feature element “gray wall” for house H82. Case 10 uses the feature element “yellow roof”. It is. In these cases, since the house H86 corresponds to the destination DES8, it cannot be used as a guide regardless of the evaluation value.

The case 11 is an example using the characteristic element “blue wall” for the house H81 and using two characteristic elements “gray wall” and “yellow roof” for the house H82. The combination coefficient is 1.0 for the house H81, but the combination coefficient is 0.5 for the house H82 because two feature elements are used. As a result, the evaluation value is 33.75 (= (the evaluation value 45 of case 1 + the evaluation value 22.5 of case 6) × 0.5).
In the case 11, the destination is guided as “a front of a house with a blue wall and a yellow roof with a gray wall”. Since this only applies to the destination DES8, it can be used as a guide.

The case 12 is an example using the characteristic element “green roof” for the house H81 and using two characteristic elements “gray wall” and “yellow roof” for the house H82. The evaluation value calculated according to the case 11 is 15.75 (= (the evaluation value 9 of the case 2 + the evaluation value 22.5 of the case 6) × 0.5). Since only the destination DES8 corresponds to the case 12, it can be used as a guide.
For the house H81, two characteristic elements “blue wall” and “green roof” are used, and for the house H82, the characteristic element “grey wall” is used for the case 13, and the characteristic element “yellow roof” is used. Case 14 was present. The evaluation value of case 13 is 22.5 (= (evaluation value 27 of case 5 + evaluation value 18 of case 3) × 0.5), and the evaluation value of case 14 is 27 (= (evaluation value 27 of case 5 + case 4). Evaluation value 27) × 0.5) is obtained. Since only the destination DES8 is applicable, it can be used as a guide.

  The case 15 is an example in which two characteristic elements “blue wall” and “green roof” are used for the house H81, and two characteristic elements “gray wall” and “yellow roof” are also used for the house H82. The combination coefficient is 0.5 for both houses H81 and H82. The evaluation value is 24.75 (= (the evaluation value of case 5 + the evaluation value of case 6) × 0, 5). The case 15 can also be used as a guide because only the destination DES8 is applicable.

Thus, for each case, if narrowing is first performed from the viewpoint of whether or not the destination DES8 can be uniquely specified, seven cases marked with ○ in the figure are extracted. Of these seven cases, the case 11 with the highest evaluation value is extracted as being suitable for guidance.
In the example of FIG. 8, the example using only the houses H81 and H82 is shown, but the evaluation may be performed using the house H85 or the like.

D4. Marker candidate extraction processing:
FIG. 9 is a flowchart of the landmark candidate extraction process. This is processing for extracting a mark by the method described in FIG.
The CPU searches for a landmark candidate as a landmark candidate within the landmark search range (step S122). What is necessary is just to search the thing which exists in a landmark search range among the features registered into guidance data.
Next, the CPU selects one of the landmark candidates (step S124). The order of selection is arbitrary, but it is preferable to select from landmark candidates close to the destination as shown in FIG.
The CPU calculates an evaluation value for each feature element of the selected landmark candidate, and searches for a feature corresponding to the guidance evaluation using the feature element within the landmark evaluation range (step S126). This processing is performed for a case where the selected landmark candidate is used alone and a combination case with other landmark candidates.
Referring to FIG. 8, when a house H81 is selected as a candidate for a mark, cases 1, 2, and 5 that use the house H81 alone are evaluated, and cases 7 to 15 that are used in combination with other houses H82. Will be evaluated.
After the processing of the house H81 is completed, when the house H82 is selected as a candidate for the landmark in step S124, the cases 3, 4, and 6 in which the house H82 is used alone are evaluated. The case used in combination with house H85 etc. will be evaluated.

Based on the evaluation result of each case, the CPU deletes cases where there are two or more corresponding features (step S128). By this processing, cases 1 to 6, 9, and 10 in FIG. 8 are deleted.
The CPU executes the above processing for all landmark candidates (step S130). A restriction may be imposed so that only the landmarks within a predetermined distance range from the destination DES8 are executed.
In this way, landmark candidates that can uniquely identify the destination are extracted and their evaluation values are also obtained. In step S140 of the landmark guidance process (FIG. 7), a case with a high evaluation value is selected. It becomes possible to do.

  According to the guide system of the present embodiment described above, the feature elements of the guide mark are structured and stored in the guide data, so that the user can appropriately combine the feature elements and guide the guide point such as the destination at the site. It is possible to present information that is not excessive or insufficient for uniquely determining the. In this embodiment, an example of guiding the destination is shown, but the present invention can be applied to various guidance points such as when guiding an intersection that turns right or left. In addition, the present embodiment is particularly useful for route guidance in an area where there is no landmark that can express features in one word, such as a residential area.

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 guidance system in the present embodiment can also be realized as a guidance method.
A computer having a map database storage unit for storing guidance data for storing a combination of feature elements structured so as to represent the position of the guidance landmark that can be a landmark when guiding a predetermined guidance point on the route and the feature thereof A current position acquisition step of acquiring position information and storing it in a memory, and a guide mark within a predetermined range set based on the guide point and the current position. Extracting from the database, comparing the structured feature elements, setting a guide mark that can uniquely identify the guide point, and one or more feature elements that are necessary to uniquely identify it The guidance information setting step stored in the memory, the characteristic elements for the guide mark stored in the memory, and the guide mark and the guide point. By presenting the location relation, a guidance method and a guide step of guiding the guide point.

Moreover, the guidance system in a present Example is realizable also as a computer program.
A computer having a map database storage unit for storing guidance data for storing a combination of feature elements structured so as to represent the position of the guidance landmark that can be a landmark when guiding a predetermined guidance point on the route and the feature thereof The current position acquisition function for acquiring position information relating to the current position and storing it in a memory, and extracting the guide mark within a predetermined range set based on the guide point and the position information from the map database, By comparing the structured feature elements, a guide mark that can uniquely identify the guide point, and one or more feature elements necessary to uniquely identify the guide point are set and stored in the memory. By presenting the guide information setting function, the characteristic elements of the guide mark stored in the memory, and the positional relationship between the guide mark and the guide point, Is a program for realizing a guide function to perform the guidance of the serial guide point.

  The present invention can be used to guide a specified destination.

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 ... Route search part 108 ... Guidance control part 200 ... Server 201 ... Transmission / reception Unit 202 ... Database management unit 210 ... Map database storage unit 211 ... Feature data 212 ... Character data 213 ... Network data 214 ... Guidance data

Claims (8)

A guidance system for guiding a predetermined point,
A map database storage unit for storing guidance data for storing a combination of feature elements structured so as to represent the position of a guide mark that can serve as a mark when guiding a predetermined guide point, and its features;
A current position acquisition unit for acquiring position information related to the current position;
Extracting a guide mark within a predetermined range set based on the guide point and the position information, comparing the structured feature elements, and a guide mark that can uniquely identify the guide point; And a guide information setting unit for setting one or more characteristic elements necessary for uniquely specifying,
A guide system comprising: a guide unit that guides the guide point by presenting the characteristic elements of the guide mark and a positional relationship between the guide mark and the guide point. The guidance system according to claim 1,
The map database storage unit further stores network data representing roads as nodes and links, and feature data for drawing features including roads,
An input section for entering a starting point and a 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 that acquires an arrival point that is a point that can be
A route search unit that performs a route search from the departure point to the arrival point with reference to the network data;
The guidance system presenting the result of the route search according to the position information together with the guidance. A guidance system according to claim 2, wherein
The route search unit further sets the guide point based on a route search result. The guidance system according to any one of claims 1 to 3,
The guidance information setting unit is a guidance system that sets a predetermined range for extracting the guidance mark based on a forefront position of a current position obtained in consideration of an error in the current position acquisition unit. The guidance system according to any one of claims 1 to 4,
Whether the guide information setting unit can uniquely identify the guide point for a range from the last position of the current position to the guide point obtained in consideration of an error in the current position acquisition unit. Guidance system that makes such judgments. The guidance system according to any one of claims 1 to 5,
The guidance data stores an evaluation value representing usefulness as the mark for each feature element,
The guidance information setting unit is configured to set a guidance mark used for guidance and its characteristic elements by evaluating the usefulness using the evaluation value when there are a plurality of uniquely identifiable guidance marks. The guidance system according to claim 6, wherein
When the guidance information setting unit can uniquely identify the guidance point by a combination of two or more guidance landmarks, the combination is also used for the guidance, and the guidance point is uniquely identified. A guide system that sets the guide mark used for the guide or a combination thereof after evaluating the usefulness of the characteristic element of each guide element as the number of necessary guide marks increases. The guidance system according to any one of claims 1 to 6,
When the guide information setting unit can uniquely identify the guide point by a combination of two or more guide marks, the combination is also used for the guide.

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