JP6177498B2 - Route guidance system - Google Patents

Description

  The present invention relates to a system for performing route guidance using an enlarged view of an intersection depicting a sign such as a vehicle traffic zone boundary line drawn on a map.

2. Description of the Related Art Route guidance systems that search for a route from a specified departure place to a destination and provide route guidance, such as a car navigation device, are widely used. The route guidance is usually performed by displaying the route and the current position on a planar or three-dimensional map. When passing through the intersection, the enlarged view is also displayed.
In order to provide route guidance that allows the user to pass through the route that has been guided without error, it is important to accurately inform the user of intersections such as right and left turns and the direction of travel there. Also, depending on the road, it may be necessary to change lanes in order to make a right or left turn, so in order to safely pass the guided route, the direction of travel at the intersection on the route should be communicated in advance as much as possible. It is preferable to keep it.
From this point of view, Patent Document 1 discloses a technique for indicating an advance direction to two adjacent intersections on a route, and indicating the advance direction to a user in advance, separately from a map representing the route. . Patent Document 2 also discloses a technology for displaying a travel direction restriction for each lane in an intersection for a plurality of intersections on the route separately from a map representing the route, and notifying the user of necessity of prior lane change. doing.

JP 2009-058375 A JP 2004-317390 A

However, the method in the prior art has a problem that it is not possible to intuitively link the guidance content in the traveling direction and the actual intersection position. It is preferable to provide information in a format that allows the user to intuitively grasp the intersection being guided in order to safely and safely pass the direction of travel of the intersection on the route. It is desirable to convey the shape and the like of the user as faithfully as possible.
Conventionally, an enlarged view of an intersection is also displayed during route guidance. However, this method displays an enlarged view of an intersection on the basis of image data prepared in advance, and guides due to the effort to prepare such image data in advance and the capacity of the generated image data. There was a problem that possible intersections were limited to major ones.
Such a problem can occur not only at the intersection but also at various branch points such as entrances and exits to toll roads and elevated roads.
In consideration of such a problem, an object of the present invention is to provide an enlarged view capable of intuitively recognizing an intersection or other branch point on a route at the time of route guidance.

The present invention is a route guidance system for guiding a route by displaying a map,
A road network database for storing road network data representing roads by nodes and links;
Based on the road network database, a route search unit for searching for a route from a specified departure place to a destination;
A drawing database that stores map polygon data for drawing roads;
A road marking regulation database that stores road marking regulation data that defines the shape and position of the vehicle lane boundary;
For the searched route, a guidance branch point to be subjected to route guidance is specified, and the guidance in which the vehicle lane boundary line is drawn based on the map polygon data, road network data, and the road marking regulation data A route guidance system including an enlarged map of a branch point, a route guidance unit that displays the enlarged map and guides the route.

According to the route guidance system of the present invention, it is possible to draw a vehicle lane border without using image data in advance by using a road marking regulation database. Since the reality of the enlarged map is improved by drawing the vehicle lane boundary line, the user can easily grasp the number of lanes at each branch point, and the guide branch point and the actual branch point It is possible to intuitively understand the correspondence.
However, in the method of the present invention, there is a possibility that the position and shape of the vehicle lane boundary line do not necessarily completely match the local state. However, even when the position and shape of the road marking are slightly different from the local state, the effect that the user who viewed the map can easily collate with the local state is easily obtained.
Here, the “branch point” is a collective term for points where a plurality of roads can be connected and a plurality of routes can be selected, such as intersections and entrances to toll roads and elevated roads.
The road marking regulation data is data that specifies the thickness, line type, position, etc. of the vehicle traffic zone boundary line based on the shape of the branch point. Based on this, an image for drawing the vehicle traffic zone boundary line This is data for generating data in the form of polygon data or raster data. The road marking regulation data can be set arbitrarily, but it is preferable to prepare it based on laws and regulations such as “commands regarding road signs, lane markings and road markings”. By doing so, since the road marking is drawn using the same rules as the actual road marking, the accuracy can be improved. However, the road marking regulation data can include not only the contents stipulated in the regulations but also other regulations.
The enlarged view can be displayed in various ways. For example, an enlarged view and a map representing a route may be displayed in parallel, or only an enlarged view may be displayed.

The drawing of the vehicle lane border may be performed after setting a branch point area based on road map polygon data. This makes it possible to demarcate the boundary line of the bifurcation area. By using the boundary line as a reference, the position and shape of road markings drawn around intersections, such as stop lines and pedestrian crossings, can be accurately set. It becomes possible to do.
Here, the branch point region can be set by various methods. For example, when map polygon data is prepared for each road, a portion where road map polygon data overlap each other may be used as a branch point region. Further, a branch point area may be set by obtaining a point corresponding to a corner of a branch point based on a distance from a node of the road network data to a road boundary line and connecting the points.
The enlarged view may also display a stop line, a pedestrian crossing, a so-called zebra zone, a traveling direction arrow, and the like in addition to the vehicle traffic zone boundary line. Data for drawing a stop line or the like may be stored in the road marking defining data.

In the present invention, the route guide section may linearize the shape of the link in the area of the guidance branch point to draw the vehicle lane boundary line.
By doing so, the shape of the link connected to the guidance branch point is simplified, and the load of the drawing process of the vehicle traffic zone boundary line based on the road marking regulation data is reduced. Further, the content of the road marking regulation data itself can be simplified.
Even when the shape of each link is linearized, it is preferable to maintain the angle between the links at the guide branch point.

In the present invention, the route guide unit is
Select a plurality of guidance branch points to be provided as the enlarged view,
It is good also as what displays in the format which can list a several enlarged view in order along the said path | route.
This mode displays a list of enlarged views of a plurality of guidance branch points. By doing so, there is an advantage that the user can know not only the latest branch point but also the shape and traveling direction of the previous branch point in advance. Based on this information, the user can change the course in advance as necessary, and can pass more safely.
A plurality of guide branch points can be presented in various ways. For example, a plurality of windows may be provided in the display screen, and an enlarged view of the guidance branch point may be displayed sequentially here. In addition, a balloon may be provided at a guidance intersection in a map for guiding a route, and an enlarged view of each may be displayed here.
It is not necessary to display a plurality of enlarged views all at the same size. For example, the most recent enlarged view may be displayed in a larger size, and the enlarged view may be displayed smaller at a guidance intersection located farther along the route. .

As described above, in an aspect of displaying an enlarged view of a plurality of guide branch points,
The route guidance unit
The enlarged views may be linearly connected and displayed on the road between the guide branch points by linearizing the shape of the links between the plurality of guide branch points.
This is a mode in which a plurality of guide branch points are not displayed in a separated state but are displayed in a connected state along a route. By doing so, the user can intuitively understand the latest guidance branch point and the guidance branch point ahead. By simplifying and showing the route between the guidance branch points with a straight line, there is an advantage that it is possible to give the user a sense of security that the user should proceed along the road without being influenced by the actual road shape.
Furthermore, information such as the distance between guide branch points and the current position may be displayed between a plurality of enlarged views. By doing so, the user can grasp the position of the next guidance intersection more accurately.

  In the case of straightening the road between the guidance branch points, various methods are conceivable when a guidance branch point that turns right or left is included on the route. For example, the display range of the enlarged view may be limited to the guidance branch point where the vehicle turns right or left. Further, the screen may be divided at the guidance branch point for turning left and right, and the rest may be displayed on another screen.

Regardless of whether or not the shape of the link between the guide branch points is linearized, in the aspect of displaying a plurality of guide branch points,
The route guidance unit
It is good also as what arrange | positions and displays each enlarged view so that the space | interval between this enlarged view may become the space | interval according to the path | route between the corresponding guidance branch points.
By doing so, the user can intuitively grasp the sense of distance to the nearest guidance branch point and the next guidance branch point.
The interval of each enlarged view does not necessarily have to be proportional to the route between the guide branch points, and the interval may be determined by a function of the route. For example, as in the three-dimensional perspective projection, the scale may be reduced as it goes further.
Further, the display size of each enlarged view may be different. For example, the display size of the enlarged view may be reduced as the distance from the current position increases. By doing so, it is possible to intuitively grasp the sense of distance to the guidance branch point.

In the present invention, regardless of whether or not to display a plurality of guidance branch points,
The road marking regulation database also stores data for defining the shape and position of the traveling direction arrow to be drawn in the vehicle lane,
The route guidance unit
The enlarged view depicting the traveling direction arrow may be displayed based on the road marking regulation database.
By doing so, the reality of the enlarged view of the branch point is further improved, and it is also possible to intuitively grasp the travel direction restriction attached to each lane. Therefore, the user can prepare for traffic at the intersection, such as changing lanes in advance as needed, and can pass more safely.
Data representing the shape of the arrow may be prepared in the form of image data such as polygon data or raster data. In this way, the advancing direction arrow can be easily displayed by pasting the image data at a specified position.

The present invention does not necessarily have all the features described above, and some of them can be omitted or combined as appropriate.
In addition to the configuration as a route guidance system, the present invention may be configured as a route guidance method for performing route guidance by a computer, or as a computer program for causing a computer to execute route guidance. Moreover, you may comprise as a computer-readable recording medium which recorded such a computer program. The recording medium may be a medium separate from the computer such as a CD-ROM or a server, or may be an internal storage device such as a RAM, a ROM, or a hard disk built in the computer.

It is explanatory drawing which shows the structure of a route guidance system. It is explanatory drawing which shows the example of the content of a road marking regulation database. It is explanatory drawing which shows the outline | summary of grouping. It is a flowchart of a road network grouping process. It is a flowchart of a route guidance process. It is a flowchart of guidance intersection data generation processing. It is a flowchart of an intersection enlarged display process. It is a flowchart of the next intersection display process. It is a flowchart of a deformation display process. It is a flowchart of a road marking display data generation process. It is a flowchart of an intersection area | region setting process. It is explanatory drawing which shows the determination method of the candidate value of the intersection angle of a pedestrian crossing. It is a flowchart (1) of a pedestrian crossing angle determination process. It is a flowchart (2) of a pedestrian crossing angle determination process. It is a flowchart (1) of road white line production | generation data processing. It is a flowchart (2) of a road white line data generation process. It is a flowchart (3) of a road white line data generation process. It is a flowchart of a pedestrian crossing data generation process. It is a flowchart of a process direction arrow data generation process. It is explanatory drawing which shows the example of a production | generation of road marking data.

A. System configuration:
FIG. 1 is an explanatory diagram showing the configuration of the route guidance system 10. The route guidance system 10 is a device that performs a route search from a departure point designated by a user to a destination and guides the route while displaying a map and an enlarged view of an intersection. In the enlarged view of the intersection, road markings such as vehicle lane boundaries are drawn. These road markings are not prepared in advance as image data, but are dynamically generated using a road network database or the like. Examples of road markings drawn in this embodiment include vehicle lane boundaries, stop lines, so-called zebra zones (hereinafter sometimes collectively referred to as road white lines), pedestrian crossings, and traveling direction arrows.

  The route guidance system 10 is configured by installing software for realizing map data generation processing in a computer including the route guidance system 10, RAM, and ROM. In the present embodiment, a configuration example as a car navigation apparatus that is a system that operates in a stand-alone manner is shown, but each element illustrated may be realized by distributed processing using a plurality of computers connected by a network or the like. .

The route guidance system 10 includes a map database 20 and a road marking regulation database 40 as databases used for route guidance.
The map database 20 has a road network database 21 and a drawing database 22. The road network database 21 stores road network data represented by nodes and links for route search. In the road network data, attribute data indicating a road type, a road name, the number of lanes, and the like are also set for each link and node. The drawing database 22 stores map polygon data for drawing a map. The map polygon data includes, for example, data for drawing roads, buildings, lakes, and the like.
The road marking definition database 40 stores the road marking definition data which is information for defining the shape and position of the road marking and dynamically generating these images. Road markings to be generated include road white lines such as stop lines and vehicle lane boundaries, pedestrian crossings, and traveling direction arrows. In this embodiment, the road marking regulation data is set based on the regulation contents of “commands relating to road signs, lane markings and road markings” (hereinafter referred to as “laws” in this embodiment). The data structure and contents will be described later.
The map database 20 and the road marking regulation database 40 may be stored in a hard disk or the like in the route guidance system 10, or may be provided from a server connected via a network. Moreover, you may provide with storage media, such as DVD.

The route guidance system 10 is provided with various functional blocks for executing route search and route guidance while utilizing the above-described database. In this embodiment, these functional blocks are configured by software by installing a computer program for realizing each function, but may be configured by hardware.
Hereinafter, the contents of each functional block will be described.

The main control unit 11 performs integrated control of the entire functional blocks, and has a function of realizing route search and route guidance by the route guidance system 10.
The command input unit 12 inputs various commands related to route search and route guidance based on user operations. Examples of the input command include designation of a route search destination, designation of a map display mode during route guidance, and the like.
The current position specifying unit 13 acquires the current position of the route guidance system 10 using GPS (Global Positioning System). A function of improving the accuracy of detection of the current position by performing so-called map matching that corrects the latitude and longitude obtained by GPS with reference to the map may be included.
The route search unit 14 refers to the road network database 21 and searches for a route from the designated departure point to the destination. The route search can take a technique such as the Dijkstra method. As the departure point, the current position detected by the current position specifying unit 13 can be used, but the user may be able to specify it.
The route guidance unit 15 performs route guidance based on the route search result by the route search unit 14. In this embodiment, the route guidance is displayed while displaying a map including the route and displaying an enlarged view of an intersection on the route.
The guidance display control unit 16 displays a map used for route guidance and an enlarged view of an intersection. To display the map, map polygon data stored in the drawing database 22 may be read and displayed. The enlarged view of the intersection is not generated by storing image data in advance, but is dynamically generated by the road marking display unit 30.

Next, functional blocks provided for the road marking display unit 30 to dynamically generate a road marking such as a road white line will be described.
The road network grouping processing unit 31 groups links and nodes on which road white lines should be drawn as a series of roads as a main road as preprocessing for generating road marking data. In the road network data, since all nodes are set at the intersections of the links, a series of links constituting the main road are also divided at each node, but such divided links are grouped together. In this way, in the generation of road marking data, it becomes possible to handle a main road or the like as a series of roads.
This process does not necessarily have to be performed dynamically. Therefore, road network data may be grouped in advance, and an identification symbol representing a group may be stored as attribute information for each link in the road network database. In the case of such an aspect, the road network grouping processing unit 31 can be omitted as the configuration of the route guidance system 10.
The intersection area setting unit 32 sets an intersection area with reference to the map polygon data and the road network data. Since road markings such as pedestrian crossings and stop lines often have positions determined based on the boundary of the intersection area, the intersection area set here has significance as a reference for determining the position of the road marking. Yes. A method for setting the intersection area will be described later.
The pedestrian crossing processing unit 34 sets the shape of the pedestrian crossing and generates data for drawing the pedestrian crossing. The pedestrian crossing is not necessarily drawn to be orthogonal to the road, and depending on the intersection, it may be drawn to cross the road diagonally. In consideration of the shape of the intersection, the pedestrian crossing processing unit 34 can draw a pedestrian crossing that intersects obliquely in this way.
The road white line data generation unit 36 generates data for drawing a road white line, a stop line, and a zebra zone. When the number of lanes increases for a right turn, the road white line data generation unit 36 also generates data for drawing a staying section in which the increased lane is drawn and a rubbing section for smoothly connecting to the staying section.

  The traveling direction arrow data generation unit 38 generates data for drawing a traveling direction arrow representing traffic restrictions such as a right turn, a left turn, and a straight travel on each lane. In the present embodiment, the shape of the traveling direction arrow is also determined dynamically based on the position and the content of regulation and the data for drawing is generated, but the shape of the traveling direction arrow is relatively limited. Therefore, a method may be adopted in which image data is prepared in advance and displayed at a position specified by road marking definition data.

B. Road marking regulation database:
FIG. 2 is an explanatory diagram showing an example of the contents of the road marking definition database 40. The road marking regulation database 40 is data that regulates the shape and position of road markings based on the legal regulation contents in order to dynamically generate data for drawing road markings. FIG. 2A illustrates the signs, contents, and numerical values of each parameter constituting the road marking definition database 40. FIG. 2B shows the significance of each parameter in association with the marking on the road. The contents of the parameters exemplified here will be described below.
The lane width WLN is the width of the lane in which the vehicle travels, and can be set to 3.0 m, for example.
The vehicle lane outermost line width and the vehicle lane boundary line width WLL are the width (thickness) of the road white line, and can be, for example, 0.15 m.
The vehicle lane boundary line length (broken line) LL is the length of the road white line drawn with a broken line, and can be set to, for example, 5.0 m.
The white line width (zebra) ZW in the current-carrying zone is the width of the white line constituting the zebra zone, and can be set to 0.45 m, for example.
The distance between white lines (Zebra) ZS in the current-carrying zone is an interval between white lines constituting the zebra zone, and can be set to, for example, 1.0 m.
The stop line width WSL is the width of the stop line, and can be set to 0.45 m, for example.
The distance DS between the pedestrian crossing and the stop line is an interval between the pedestrian crossing and the stop line, and can be set to 2.0 m, for example.
The lane change prohibition line DPC in front of the stop line is the length of the section in which the road white line should be drawn with a solid line instead of a broken line until the stop line is prohibited, for example, 30.0 m Can do.
The pedestrian crossing line width WCW and the line interval SCW are the widths and intervals of the white lines constituting the pedestrian crossing, and can be both 0.45 m, for example.
The traveling direction arrow position DA represents the position where the traveling direction arrow shown in the lane is drawn by the distance from the stop line to the tip of the arrow, and can be set to 2.0 m, for example. Different values may be used depending on the shape of the arrow, such as a straight arrow or a right / left turn arrow.
In this embodiment, these numerical values are set based on laws and regulations. In addition to this, various parameters that determine the position and shape of the road marking can be set in the road marking definition database 40. Further, not all parameters need to be set based on laws and regulations, and parameters that are not regulated by laws and regulations may be defined in order to accurately reproduce the actual state.

C. Road network grouping:
Next, grouping of road networks corresponding to preprocessing for generating road markings in the present embodiment will be described. In the present embodiment, the configuration in which the road network grouping processing unit 31 dynamically performs processing is illustrated, but the processing described below is performed in advance, and the result is stored in the road network database 21. It is also possible to leave. Below, after showing the meaning and outline | summary of a process first, a flowchart is shown.

FIG. 3 is an explanatory diagram showing an outline of grouping.
FIG. 3A shows a road in which a link L53 of a narrow street intersects with links L51 and L52 constituting the main road at a node N50. In road network data, a node is always set at the intersection of links regardless of the road type. Accordingly, the links L51 and L52 constituting the main road are also stored on the road network data in a state of being divided into a plurality of links, and the node N50 is recognized as an intersection. An intersection area A50 (hatched portion) is set around the node N50 by a processing method described later. Since the road white line is usually drawn avoiding the intersection area, as a result of setting the intersection area A50, the road white line divided as road white lines LL51 and LL52 is drawn for the main road. Become.
However, in general, for a portion where a narrow street intersects with a main road, the road white line of the main road is usually drawn continuously without being divided as shown in FIG.
Therefore, in the network grouping process, links and nodes that should not generate intersection areas, such as intersection area A50, are defined as groups. In the example of FIG. 3A, in the process of generating road marking data in the direction D51, the link L51, the node N50, and the link L52 are defined as a group. In this way, when the road marking data is generated for the links L51 and L52, it is recognized that these links and nodes should be handled as a series, and the setting of the intersection area A50 is avoided. The road white lines LL51 and LL52 can be generated in a continuous state.
Conversely, no grouping is performed in the process of generating road marking data in the direction D52. By doing so, since the intersection area A50 is set, the road outermost lines LL53 and LL54 can be generated in a state of being divided by the intersection area A50.
Consider a case where road marking data of link L53 is generated for this intersection. The link L53 is not defined as a group in any of the links L51 and L52. In this way, at the time of processing the link L53, the intersection area A50 around the node N50 can be set, and a stop line and a crosswalk can be drawn on the straight line of the intersection.

FIG. 3B shows another example in which grouping should be performed. In the example shown in the figure, links L58 and L59 that run in parallel across a relatively narrow separation band M51 intersect with links L54 to L57 at nodes N51 and N52. Such a situation can occur in places such as urban areas where the vertical lines are separated by the separation band M51.
When processing is performed without grouping in such a place, the node N51 is recognized as an intersection, and the intersection area A51 is set. This is because the position of the node N52 and the link L59 is not considered when processing the node N51. When the intersection area A51 is set, a pedestrian crossing is set based on the intersection area A51. Therefore, the pedestrian crossing CW51 is set so as to cross the separation zone M51.
Therefore, in the network grouping process, when the process is performed in the D53 direction, the link L55, the node N51, and the link L54 are defined as a group. By doing this, it is possible to exclude the node N51 and set an intersection area only around the node N52, so that it is possible to generate the pedestrian crossing CW52 instead of the unnatural pedestrian crossing CW51.
When processing in the D54 direction, the link L55, the node N52, and the link L56 are defined as a group. By doing so, it is possible to exclude the node N52 and set an intersection area only around the node N51, so that a pedestrian crossing CW53 can be generated.
For the other links L57, L58, and L59, if a process is performed without defining a group, it is possible to generate a pedestrian crossing at an appropriate position.
As described above, as shown in FIGS. 3 (a) and 3 (b), by performing grouping, it is possible to switch whether or not to set an intersection area, and to reflect the situation of each intersection A sign can be generated. Next, specific processing for grouping will be described.

FIG. 4 is a flowchart of the road network grouping process.
The route guidance system 10 reads road network data (step S1), and selects a node to be processed for grouping (step S2). Then, a link connected to this node is extracted (step S3).
Next, the route guidance system 10 determines the road conditions for the extracted links (step S4). The road condition is a condition for judging whether or not a plurality of links divided by nodes should be treated as a series of roads in the generation of road marking data, and is a basis for judgment for grouping. It is a condition. In this embodiment, it is assumed that whether or not the road is a road is set individually in the vertical direction of each link as an attribute in the road network data.
A three-way road composed of links L1 to L3 shown in the figure is illustrated. Among these, the direction P12 from the link L1 to the link L2 and the direction P21 from the link L2 to the link L1 are set to be “roadways”, and the other directions (link L1 → L3, etc.) are It is assumed that “Road” is not set. Based on this attribute, the route guidance system 10 extracts the result of whether or not each link is a road as shown in the figure.
Whether it is a road or not may be determined analytically based on the road type, road name, lane width, shape, etc., in addition to being set as an attribute. For example, it is determined that links with the same road name and road type are determined to be roads, or that the links are determined to be roads if the angle between the links is within a predetermined range from 180 degrees. Can do.

When the determination of the road condition is completed, the route guidance system 10 performs grouping based on the determination result (step S5). In this embodiment, a group is set when any one of cases 1 and 2 shown in the figure is satisfied. A case where the link La is a processing target will be described as an example with respect to the three-way road including the links La, Lb, and Lc shown in the drawing.
Case 1 is a case where, in step S4, it is determined that both the direction Pab of the link La → Lb and the direction Pba of the link Lb → La are on the road.
Case 2 is a case where, in step S4, it is determined that only the direction Lab of the link La → Lb is a road, and it is determined that the link Lc and the links La and Lb are not a road.
Cases 1 and 2 are set as a result of investigating a portion that is not handled as an intersection on an actual road. If grouping is performed according to this condition, road white lines can be appropriately generated in the cases shown in FIGS. 3 (a) and 3 (b). However, various conditions can be set as the grouping condition, and conditions other than those shown in step S5 can be used.
If the link La in the above condition is replaced with the link Lb or the link Lc, the grouping condition for these links can be set. In step S5, the route guidance system 10 performs grouping determination for all links connected to the processing target node. The route guidance system 10 repeatedly executes the above processing until all the nodes are finished (step S6).

D. Directions:
Next, route guidance by the route guidance system 10 will be described.
FIG. 5 is a flowchart of route guidance processing. When the process is started, the route guidance system 10 inputs a departure place and a destination (step S10). The destination can be set in various manners by the user's operation. As the departure point, the current position specified by the current position specifying unit 13 may be used, or a point designated by the user may be used.
Next, the route guidance system 10 searches for a route from the designated departure point to the destination (step S12). The route search can be performed by referring to the road network data 21 and using a method such as the Dijkstra method.
When the route is obtained in this way, the route guidance system 10 performs guidance intersection data generation processing (step S20). This process is a process for extracting a guidance intersection, that is, an intersection for which an enlarged view of the intersection is displayed during route guidance. Here, the guidance intersection data generation process will be described once away from FIG.

  When the road network grouping described in FIGS. 3 and 4 is dynamically performed, it is preferable to perform these processes along the obtained route after the above route search is completed.

D1. Guided intersection data generation processing:
FIG. 6 is a flowchart of the guidance intersection data generation process. In this process, the route guidance system 10 reads a route search result (step S22), and extracts a guidance intersection according to the following conditions a to d (step S24). All of these conditions are conditions for extracting an intersection that is likely to be erroneous when the user passes the guided route. In the embodiment, “intersection” is used as a broad term including a branch point such as an entrance to a toll road.
Condition a: intersection that turns right and left;
Condition b: an intersection that follows a route that is not a road;
Condition c: entrance / exit of toll road and elevated road;
Condition d:
Intersections where the number of lanes on the intersecting road is greater than or equal to the number of lanes on the route in progress;

An example of extracting a guidance intersection is shown on the right side of the figure. In this example, intersections IS1 to IS6 exist on the route from the departure point to the destination. For these intersections, other than the intersection IS2 is extracted as a guide intersection according to the conditions shown in the table.
For example, the intersection IS1 is a straight-ahead intersection, but is extracted as a guidance intersection because it corresponds to the condition d “the number of intersections on the intersecting road is greater than or equal to the number of lanes on the route in progress”. This is because a user tends to select a main road when traveling in an unknown area, and thus may make a right or left turn accidentally when attempting to cross a road that is wider than an ongoing road.
Since the intersection IS3 is a road connected to the interchange IC of the toll road, it is set as a guidance intersection according to the condition c.
Intersections IS4 and IS5 are intersections that turn left and right, respectively, and are therefore guided intersections according to condition a.
The intersection IS6 is a Y-junction, and if it goes to the right along the road, it will deviate from the route.
The extraction conditions for the guidance intersection can be set arbitrarily, and some of these may be omitted, or additional conditions may be provided.

The route guidance system 10 calculates the distance between the intersections (the route along the route) for the extracted guidance intersection (step S26). As shown in the table on the right side of the figure, the distance from the departure point is calculated for the guidance intersection IS1. Since the intersection IS2 is not a guide intersection, the distance is not calculated. For the guidance intersection IS3, the distance from the guidance intersection IS1 is calculated. The same applies to other intersections. The distance between the intersections calculated here is used later for displaying an enlarged view of the intersection at the time of route guidance.
The route guidance system 10 stores the result thus obtained as guidance intersection data (step S28). The contents of the guidance intersection data may include the intersection identification information and the distance between the intersections shown in the table in the figure. Extraction conditions can be omitted.
In the present embodiment, the guidance intersection is extracted and the distance between the intersections is calculated prior to the route guidance. However, these processes may be sequentially performed in the course of the route guidance.

D2. Route guidance process:
Returning to FIG. 5, the route guidance process will be described. When the route guidance system 10 ends the guidance intersection data generation process (step S20), the route guidance system 10 performs route guidance according to the following procedure.
That is, the route guidance system 10 inputs the current position (step S30), and according to the guidance display mode (step S32), the intersection enlarged display process (step S40), the next intersection display process (step S50), and the deformation display process. While displaying a guidance screen such as (Step S60), route guidance is performed until the destination is reached (Step S70). The intersection enlarged display process (step S40) is a process for supporting the passage by appropriately displaying an enlarged view of the guidance intersection along with route guidance by a map. The next intersection display process (step S50) is a process of displaying an enlarged view of the nearest guide intersection that passes and an enlarged view of the next guide intersection that is scheduled for currency. The deformation display process is a process of displaying an enlarged view of a plurality of passing guide intersections in a state where they are linearly arranged.
Hereinafter, the contents of each display process will be described in order.

D3. Crossing magnified display:
FIG. 7 is a flowchart of the intersection enlargement display process. This process corresponds to step S40 in FIG.
A display example is shown on the right side of the figure. In this display mode, a map for guiding the route is displayed on the screen 1, and an enlarged view of the next intersection is displayed on the screen 2 on the right side. Various timings can be set for displaying the enlarged view of the intersection. For example, it may be displayed when it approaches a predetermined distance to the guidance intersection, or an enlarged view of the next guidance intersection may be displayed when it passes through a certain guidance intersection. Hereinafter, a processing example will be described assuming that an enlarged view is displayed near the guidance intersection.
In this process, the route guidance system 10 determines whether or not the current position is near the guidance intersection (step S41). What is necessary is just to judge by the distance from the present position to the guidance intersection to pass next is below a predetermined value.
If it is not near the intersection (step S41), the route guidance system 10 displays a guidance map on the entire screen (step S42). What is necessary is just to draw a map using the map polygon data stored in the drawing database 22. Although an example in which a two-dimensional map is displayed is shown here, a three-dimensional map may be displayed.
If it is near an intersection (step S41), the route guidance system 10 executes a road marking display data generation process (step S100). This process is a process for generating polygon data (hereinafter, referred to as “road marking polygon”) for drawing road markings such as intersections and road white lines in the vicinity thereof. The processing contents will be described later. Then, the route guidance system 10 performs the enlarged guidance display of the intersection using the road marking polygon (step S43).
As shown in the screen 2 in the figure, in this embodiment, in the enlarged view near the intersection, the vehicle lane border, the stop line, the pedestrian crossing, the traveling direction arrow, and the like are drawn in detail. All of these road markings are drawn using road marking polygons dynamically generated by the road marking display data generation processing (step S100). In the enlarged view, an arrow indicating the route is also displayed.
By displaying an enlarged view of a realistic intersection in this way, the user can intuitively determine whether or not the immediate intersection is a guidance intersection, and can pass through the route without error. In the enlarged view, the number of lanes and arrows in the direction of travel are displayed, so the user can know in advance that a lane change is necessary to make a right turn, etc., and can safely pass through the guidance intersection. It becomes.

D4. Next intersection display:
FIG. 8 is a flowchart of the next intersection display process. This process corresponds to step S50 in FIG.
A display example is shown on the right side of the figure. In this display mode, a map for guiding the route is displayed on the screen 1, and an enlarged view of the next intersection to be passed is displayed on the right screen 2, and an enlarged view of the next intersection to be passed is displayed on the screen 3. The screens 2 and 3 may be in the reverse order. Further, more screens may be provided so that enlarged views of a large number of guidance intersections can be displayed. Moreover, it is also possible to provide a balloon at the guidance intersection in the screen 1 and display each enlarged view.

In this process, the route guidance system 10 reads two guidance intersections ahead of the current position (step S51). Then, the distance from the current position to the next guidance intersection is calculated (step S52). Although the distance between the guidance intersections has already been calculated (see step S26 in FIG. 6), the distance from the current position to the next guidance intersection changes with the movement of the current position, and thus needs to be calculated again. Because.
Then, the route guidance system 10 executes a road sign display data generation process (step S100). This process is a process for generating polygon data (hereinafter, referred to as “road marking polygon”) for drawing road markings such as intersections and road white lines in the vicinity thereof. The points for generating road marking polygons around the guidance intersection are the same as when the road marking display data generation processing is executed in the intersection enlarged display processing (FIG. 7), but here the road marking polygon is generated. The difference is that there are two guided intersections.
When the road marking polygon is generated in this way, the route guidance system 10 displays an enlarged view of the intersection as shown in screen 2 and screen 3 in the figure (step S53). Further, the distances to the respective guidance intersections are displayed together on the screen 2 and the screen 3, respectively.
Thus, by displaying a plurality of guidance intersections, the user can grasp in advance the route after passing the next guidance intersection. For example, taking into account turning right at the previous guidance intersection, the user can easily take measures such as stopping in front of the right lane when passing the nearest guidance intersection. Therefore, it is possible to pass the guide intersection more safely.
In this embodiment, the distance to each guidance intersection can be grasped by displaying the distances on the screens 2 and 3. Therefore, it is possible to make preparations such as lane selection in consideration of the distance to the next guidance intersection, and it is possible to travel with ease.

D5. Deformed display:
FIG. 9 is a flowchart of the deformation display process. This process corresponds to step S60 in FIG.
A display example is shown on the right side of the figure. In this display mode, a map for guiding a route is displayed on the screen 1, and enlarged views of a plurality of guidance intersections are displayed on the screen 2 on the right side. However, unlike the next intersection display process (see FIG. 8), the feature of this display mode is that a plurality of guided intersections are displayed as a series of routes connected by roads therebetween. By displaying the guide intersections as a series of routes without separating them in this way, the user can intuitively understand the nearest guide intersection and the next guide intersection as continuous intersections on the route. become able to.
In this display mode, the road between the guidance intersections is displayed with a straight line. In this way, showing the route between the guidance intersections with a straight line has the advantage that the process of generating the road marking data is simplified, but not only that, but also the actual road shape for the user. There is also an advantage that it is possible to give a sense of security that it is only necessary to proceed along the way without being influenced by. As shown in the screen 2, an enlarged view obtained by straightening a road is called a deformation guidance display in this embodiment.

When there is a guidance intersection that turns right or left along the route, the deformation guidance display is performed in the range up to the guidance intersection that turns right or left. After passing the guidance intersection, the deformation guidance display ahead is displayed again.
As another mode, the deformation guidance display up to the guidance intersection that turns right and left may be displayed, and the next deformation guidance display from the guidance intersection may be performed on a separate screen as in the next intersection display (FIG. 8). .

In this process, the route guidance system 10 reads a plurality of guidance intersections ahead of the current position (step S61), and calculates the distance from the current position to the next guidance intersection (step S62).
Then, the route guidance system 10 executes a road sign display data generation process (step S100). This process is the same as the process in other display modes (step S100 in FIGS. 7 and 8). In this display mode, road marking data is generated not only for the intersection but also for the road between the intersections. Is different. The route guidance system 10 performs deformation guidance display (screen 2) using the road marking polygon (step S63).
By displaying a plurality of guided intersections in this way, as with the next intersection display mode, the user can proceed while being aware of the passage of the previous guidance intersection, and more safely guide passages and routes can be passed. There is an advantage to become. In addition, since the guidance intersection is presented in a straight line and simple state, it is possible to avoid giving excessive information to the user when the guided route is advanced, and there is an advantage that the route can proceed without error. .

E. Display of road markings:
FIG. 10 is a flowchart of the road marking display data generation process. Polygon data for drawing road white lines at intersections, etc., which are commonly used in the intersection enlargement display process (FIG. 7), the next intersection display process (FIG. 8), and the deformation display process (FIG. 9). It is a process to generate.

In this process, the route guidance system 100 includes an intersection area setting process (step S200), a pedestrian crossing angle determination process (step S300), a road white line data generation process (step S400), a pedestrian crossing data generation process (step S500), and Each of the advancing direction arrow data generation processing (step S600) is executed to generate polygon data for road marking.
Hereinafter, each processing will be described.

E1. Intersection area setting:
FIG. 11 is a flowchart of intersection area setting processing. This process corresponds to the function of the intersection area setting unit 32 (see FIG. 1).
In this process, the route guidance system 10 selects a processing target node (step S202). At this time, the nodes on the grouped links are excluded from the processing targets by the above-described road network grouping processing (FIGS. 3 and 4).
The route guidance system 10 reads map polygon data around the processing target node from the drawing database 22 and acquires a road area (step S204). The state of the process is illustrated on the right side in the figure. When the node N70 is a processing target node, the road area (white portion in the figure) corresponding to the links L71 to L74 connected thereto is specified. It is not always necessary to acquire map polygon data of the road itself, and map polygon data of a background portion other than the road (hatched portion in the figure) may be acquired.
As shown on the right side, the road area around the processing target node N70 is divided into four areas I to IV by links L71 to L74. The route guidance system 10 acquires the intersection, that is, the nearest point from the processing target node N70 for each of the regions I to IV (step S206). As shown in the figure, point P1 for region I, point P2 for region II, point P3 for region III, and point P4 for region IV are the nearest points.
When the nearest neighbor is found, the route guidance system 10 connects these and sets an intersection area (step S208). In the figure, a portion surrounded by a thick line connecting points P1, P2, P3, and P4 is an intersection region. The route guidance system 10 repeatedly executes the above processing until all the nodes are finished (step S210).
The intersection area set in this way is used as a reference for the position when the white road line is drawn.

E2. Crosswalk angle determination:
The pedestrian crossing is not necessarily drawn so as to be orthogonal to the edge of the road, and depending on the shape of the intersection area, the pedestrian crossing may be drawn obliquely with respect to the road. Therefore, first, after determining the angle for drawing the pedestrian crossing based on the shape of the intersection area, drawing data for the pedestrian crossing is generated. This process is a process corresponding to the function of the pedestrian crossing processing unit 34 (see FIG. 1).
In the following, a method for determining the crossing angle of a pedestrian crossing is first described, and then a flowchart thereof is shown.

FIG. 12 is an explanatory diagram showing a method of determining candidate values for the intersection angle of a pedestrian crossing. The example of setting the four candidate values of FIGS. 12A to 12D is shown by taking the case where the link L81 is a processing target at the intersection where the links L81 to L84 intersect.
FIG. 12A shows an example in which a pedestrian crossing WC81 orthogonal to the link L81 is set. As shown in the figure, at the intersection where the roads intersect diagonally, if it is drawn like a pedestrian crossing WC81, the space to the intersection is opened on the right side of the link L81 (link L84 side), and it becomes an unnatural state. . In such a case, it is preferable to draw the pedestrian crossing obliquely in a state of rising to the right in the drawing.
12B to 12D are examples in which a pedestrian crossing WC82 is set obliquely with respect to the link L81. The pedestrian crossing WC82 in FIG. 12B is drawn by a parallelogram having sides parallel to the link L83 intersecting the left side of the link L81. The pedestrian crossing WC83 in FIG. 12C is drawn by a parallelogram having sides parallel to the link L84 intersecting the right side of the link L81. The pedestrian crossing WC84 in FIG. 12D has points P83 and P84 that are equidistant from the node N on the links L83 and L84, and has a parallelogram having sides parallel to the line segment connecting these points P83 and P84. be painted. It can also be said to be a parallelogram having a side whose normal is the bisector of the corner between the links L83 and L84.
In this embodiment, one of the three candidate angles shown in FIGS. 12B to 12D is selected according to the intersection, and the intersection angle of the pedestrian crossing is determined. The determination method will be described according to the following flowchart.

13 and 14 are flowcharts of the pedestrian crossing angle determination process.
The route guidance system 10 first selects a processing target link, and acquires an intersection link that intersects the processing target link (step S302). Although it is possible to acquire all the links that intersect the processing target link, in this embodiment, the acquisition is limited to those satisfying the following conditions 1 and 2. Here, “A9 *” is an angle between the link L9 * (* = 1, 2,...) Intersecting the processing target link and the processing target link.
Condition 1: | A9 * -90 ° | is minimized on both sides of the processing target link;
Condition 2: 90 ° −TH ≦ A9 * ≦ 90 ° + TH;
Condition 1 is a condition for selecting a link that intersects the processing target link at an angle closest to 90 ° one by one on both sides of the processing target link. Condition 2 is a condition that the angle between the selected link and the processing target link is within a predetermined range from a right angle. Under these conditions, a link that intersects at an angle close to a right angle is obtained on both sides of the processing target link.

The above conditions 1 and 2 are illustrated in the figure. Assume that at the node Nob at the end of the processing target link Lob, the links L91 and L93 intersect on the left side and the link L92 intersects on the right side. The angles between the processing target link Lob and the links L91 to L93 are represented by A91 to A93, respectively. The hatched portion in the figure represents a range that satisfies the condition 2. That is, the boundary line BL1 is a line whose angle with the processing target link Lob is “90 ° −TH”, and the boundary line BL2 is a line whose angle is “90 ° + TH”. In the state shown in the figure, since the links L91 to L93 are all within the hatched area, the condition 2 is satisfied.
Only the link L92 exists on the right side of the processing target link Lob. Therefore, in the condition 1 that | A9 * −90 ° | is the minimum, the link L92 is selected without comparing with other conditions.
Links L91 and L93 exist on the left side of the processing target link Lob. Of these, the link L91 intersects the processing target link Lob at an angle close to a right angle. Therefore, on the left side, the link L91 is selected according to the condition 1. If expressed in a form corresponding to condition 1, | A91−90 ° | <| A93−90 ° |.

When the intersection link is acquired in this way, the route guidance system 10 calculates the left and right intersection angles (step S304). The definition of the left / right crossing angle is shown in the figure. In order to avoid complication of the figure, the left and right parts are shown separately. The left figure shows the left intersection angle, and the right figure shows the right intersection angle. The left intersection angle is defined by an angle AN91 between the normal line NL91 of the link L91 intersecting the left side and the processing target link Lob. The right intersection angle is defined by an angle AN92 between the normal line NL92 of the link L92 that intersects the right side and the processing target link Lob. Since the evaluation of the left crossing angle and the right crossing angle is performed using absolute values, it is not necessary to consider the sign of positive or negative depending on whether the angles AN91 and AN92 appear on the left or right of the processing target link.
When the pedestrian crossing is drawn using the left crossing angle, the state shown in FIG. 12B is obtained. When the pedestrian crossing is drawn using the right crossing angle, the state shown in FIG. 12C is obtained.
Next, the route guidance system 10 calculates an average intersection angle (step S306). As shown in the figure, the average intersection angle is an angle AN93 between the bisector NL93 of the left and right intersection links L91 and L92 and the processing target link Lob. When a pedestrian crossing is drawn using this angle, the state shown in FIG.

The route guidance system 10 sets the minimum value of the left and right intersection angles and the average intersection angle obtained above as the pedestrian crossing angle (step S308). The angle was evaluated as an absolute value. Drawing of a pedestrian crossing at the set pedestrian crossing angle is performed by a pedestrian crossing drawing process (FIG. 18) described later.
The route guidance system 10 repeatedly executes the above processing until it ends for all links (step S310).

E3. Generation of road white line data:
15 to 17 are flowcharts of the road white line generation process. This process is a process content corresponding to the function of the road white line data generation unit 36 (see FIG. 1).
When the process is started, the route guidance system 10 acquires a link group to be processed (step S402). Then, the link group is linearized (step S404). The linearization method is shown in the figure. As shown in the upper side of the figure, a link group including links L111 and L112 and nodes N111 to N113 is considered. It is assumed that this link group is defined by a broken line that is bent along the road shape.
In the linearization process, as shown on the lower side of the figure, the nodes N111 to N113 are mapped onto one-dimensional coordinates while maintaining the lengths of the links L111 and L112. The mapped results are referred to as linearization links L111s and L112s and linearization nodes N111s to N113s.

  The range of link groups to be processed and linearized are selected according to the display mode. In the case of the intersection enlargement display process (FIG. 7) and the next intersection display process (FIG. 8), the range around the intersection that is the display target of the enlarged view may be the processing target and the linearization target. In the case of the deformation display process (FIG. 9), since the route between the intersections is also shown as a straight line, it is necessary to set the entire route as a processing target and a straightening target. However, if there is a guidance intersection that turns right or left in the middle of the route, the range up to the guidance intersection may be divided into a section and the object to be processed and straightened.

The route guidance system 10 determines the positions of the outermost vehicle line and the center line (step S406). These determination methods are shown in the figure. The determination method is as follows.
The road network data includes road width Wrd and the number of lanes as road attributes. The road marking definition data (see FIG. 2) has the lane width as a parameter. Accordingly, by calculating the lane width × the number of lanes using these data, the width D used for the lane among the road width Wrd is determined. By arranging the width D evenly within the road width Wrd, the positions of the vehicle lane belt outermost lines BL1 and BL2 can be determined. Moreover, the position of the center line CL can be determined by dividing the width D by the number of lanes on the upper and lower lines. Since the number of lanes of the upper and lower lines is not necessarily the same, the center line CL does not necessarily come to the center of the width D. For example, on a road with two lanes going up and one lane going down, the center line is set at a position where the width D is internally divided by 2: 1.

When the center line is set in this way, the route guidance system 10 divides the road up and down by the center line and generates road marking data for each. Specifically, an intersection area, a pedestrian crossing area, and a stop line are set, and the outermost line length and the center line length of the vehicle lane are corrected based on the results (step S408).
An example of processing is shown in the figure. Consider a case where processing is performed in the direction D12. The route guidance system 10 arranges the intersection area CS set in the intersection area setting process (FIG. 11). Then, based on the pedestrian crossing angle determined in the pedestrian crossing angle determination process (FIGS. 13 and 14), the reference line LCS0 is drawn from the end point of the intersection area. An angle ACS between the reference line LCCS0 and the processing target link L11s corresponds to a pedestrian crossing angle.
Next, a pedestrian crossing area CW is set as a parallelogram having a predetermined width LCW at a position shifted by a predetermined distance OST from the reference line LCS0 in a direction away from the intersection area. These distance OST and width LCW may be set in the road marking regulation data.
The route guidance system 10 cuts the vehicle traffic zone outermost line BL2 and the center line CL at the boundary line of the pedestrian crossing area CW. Further, the stop line SL is set at a position shifted from the intersection of the center line CL and the pedestrian crossing area CW by the distance DS between the pedestrian crossing and the stop line. In addition, a vehicle lane boundary line is set in parallel to the vehicle lane outermost line BL2 and the center line CL according to the number of lanes.
A road marking can be drawn on the down line in the same manner. The procedure described here is only an example, and may be generated by another method / procedure.

The route guidance system 10 calculates a slag length Lt and a required stagnation length Ls in order to generate a stay section and a rubbed section for the lane increase portion (step S410). These lengths can be calculated as follows based on the law.
Required residence length Ls = 1.5 × N × S;
Rubbing length Lt = V × WLN / 6;
N: Average number of stays per cycle;
S: Average vehicle head distance (distance between the heads of the front and rear vehicles);
V: Design speed;
WLN: Lane width;
Of the above parameters, the lane width may be stored in the road marking definition data as a value common to all roads. Since the parameters N and V are values specific to the road, it is preferable to set them as attributes in the road network data. These default values may be set in the road marking regulation data. For example, the design speed V can be set according to the number of lanes, such as 30 km / h for a one-lane road, 40 km / h for a two- to three-lane road, and 50 km / h for four or more lanes.
The parameter S may be set as an attribute of road network data, considering a value unique to the road, or may be set in the road marking definition data as a value common to all roads.
Furthermore, these default values may be set for the case where the above-mentioned parameters are insufficient and the necessary staying length Ls and rubbing length Lt cannot be calculated. For example, the necessary staying length Ls can be the same value as the distance DPC (see FIG. 2) of the lane change prohibition line before the stop line.

The route guidance system 10 adjusts the calculated rubbing length Lt and the required staying length Ls so that the staying section and the rubbing section are within the road length (step S412). For the road length, the outermost vehicle lane and the minimum value min of the center line are used as the reference value Lrd. The reason why the minimum value min is used is that, as depicted in step S408 of FIG. 16, the pedestrian crossing area is set obliquely, and the length of the center line may differ from the outermost side of the vehicle lane. is there.
As shown in the upper side of the figure, consider a case where “necessary staying length LS0 + rubbing length Lt0” is larger than the reference value Lrd. In such a case, as shown in the figure, the staying section and the rubbing section are protruded from the road.
In this embodiment, in such a case, the necessary retention length is shortened while ensuring the rub length, so that the sum of both is adjusted to be equal to or less than the reference value Lrd. The adjustment results are shown in the lower part of the figure. In this example, the rubbing length Lt1 is the same as the initial length Lt0, and the required length Ls1 is made shorter than the initial length Ls0, so that the entire length falls within the reference value Lrd. In this aspect, even if the required staying length Ls is reduced to a preset limit such as the length of one vehicle, if the total length exceeds the reference value Lrd, the rubbing length Lt is reduced. It will be. However, various adjustment methods can be used for the necessary residence length and the rub length, and a method of shortening both at a fixed ratio can also be used.

The route guidance system 10 polygonizes each white line set in the above processing (step S414). A white line here means a stop line, a center line, and a road white line (a vehicle traffic zone outermost line, a vehicle traffic zone boundary line). The pedestrian crossing is not yet drawn at this point.
The route guidance system 10 combines the upper and lower road marking data with the center line, and then sets the gap between the upper and lower rubbing sections as a guiding fluid (zebra zone) (step S416). The zebra zone ZZ set in the gap between the upper and lower rubbing sections LSA and LSB is illustrated in the figure. The width and interval of the white lines constituting the zebra zone are defined in the road marking definition data (see FIG. 2).
The route guidance system 10 repeatedly executes the above processing until all the groups are completed. With these processes, generation of road markings excluding pedestrian crossings is completed.

In the present embodiment, road marking data is generated after linearly linking a polygonal line link, and an enlarged view is displayed using the road marking data. When displaying the enlarged map in a state that reflects the shape of the road without straightening, after generating the straight road marking data, return the link shape to the original shape, and according to this, What is necessary is just to perform the process which deform | transforms road marking data.
Such processing can be performed, for example, by the following procedure. First, the generated road marking data is divided for each linearized link. Then, the divided road marking data is arranged on the original link in the original polygonal line shape. As a result of this arrangement, an area where polygons overlap and an area where gaps occur are generated. For these areas, the polygons may be smoothly interpolated between the polygons according to the link shape.

E4. Generate crosswalk data:
FIG. 18 is a flowchart of pedestrian crossing data generation processing. The route guidance system 10 reads the pedestrian crossing area set in step S408 of FIG. 16 (step S502).
Then, crosswalk polygon data is generated in this area (step S504). Parameters set in the road marking definition data are used for the width WCW and the interval SCW of the white lines PCW1 to PCW3 constituting the pedestrian crossing. When the pedestrian crossing area CW is a parallelogram, the shape of each of the white lines PCW1 to PCW3 is also a parallelogram composed of sides parallel to the side of the pedestrian crossing area CW.
The route guidance system 10 repeatedly executes the above processing until all the pedestrian crossing areas are completed (step S506).
The pedestrian crossing can also be drawn together when the pedestrian crossing area is set in step S408 of FIG.

E5. Generation of direction arrow data:
FIG. 19 is a flowchart of the direction arrow data generation process. This corresponds to the function of the traveling direction arrow data generation unit 38.
The route guidance system 10 reads the information of the traveling direction arrow for each lane of the guidance intersection (step S602). The information of the traveling direction arrow can be stored in the form of the exit angle α for each lane, for example. An example of information storage is shown in the figure. Lane 3 is a right turn lane, and exit direction 3 is a direction of 270 degrees with reference to the approach direction to the intersection. Therefore, for lane 3, information of α = 270 ° is recorded as arrow 1 (meaning the first arrow). Lane 2 is a straight lane, and the exit direction 2 is 0 degrees. Therefore, information that α = 0 ° is recorded as the arrow 1 for the lane 2. Lane 1 is a lane that goes straight and turns left. Therefore, information of α = 0 ° indicating straight travel is recorded as the arrow 1, and α = 90 ° indicating left turn is recorded as the arrow 2 (meaning the second arrow). When a plurality of pieces of information are recorded as indicated by arrows 1 and 2, it means that an arrow combining these as in lane 1 is drawn.

The information of the traveling direction arrow may be stored by other methods. For example, since the shape of the traveling direction arrow is relatively limited, such as straight ahead, left turn, straight forward + left turn, etc., a method of storing codes representing these shapes may be used. According to this method, there is an advantage that the information of the traveling direction arrow can be set and stored in a relatively simple format.
Depending on the shape of the intersection, the exit angle is not limited to 90 °, and there are also intersections with special shapes such as five-forks. Therefore, according to the mode shown in FIG. There is an advantage that it can respond.

  Next, the route guidance system 10 sets the drawing position of the arrow of each lane according to the information of the traveling direction arrow (step S604). As shown in the drawing, the position in the lane width direction is set so that the shaft portion of the arrow is located at the center of the lane width. Further, the position in the direction along the lane is set so that the tip of the arrow becomes a position corresponding to the traveling direction arrow position DA stored in the road marking definition data. Here, an example of a straight-going arrow is shown, but the same applies to a right-left turn arrow.

Then, the route guidance system 10 generates arrow polygon data (step S606). The shape of the arrow can be generated by storing the thickness of the arrow, the shape of the arrow portion, and the like in advance in road marking defining data, and combining them in accordance with the traveling direction arrow information read in step S602. For the direction arrows that are frequently used, such as going straight and turning left and right, the arrow polygon data itself is stored in the road marking regulation database or the drawing database, and this image data is arranged at the arrow drawing position set in step S604. Thus, a method of generating arrow polygon data may be taken.
The route guidance system 10 generates the polygon data of the direction arrow in the intersection area by the above processing, and displays these.
Thus, according to the enlarged view of the present embodiment, by displaying the traveling direction arrow, the reality of the guidance intersection is improved, and the actual intersection and the guided intersection can be intuitively associated with each other. . Moreover, since the traffic regulation of each lane can be grasped by an enlarged view, the user can change the lane in advance, and the traffic safety can be improved.

E6. Example of road marking data generation:
FIG. 20 is an explanatory diagram illustrating an example of generation of road marking data. FIG. 20A shows a generation example according to the present embodiment, and FIG. 20B shows an aerial photograph of the corresponding region.
At first glance, the pedestrian crossing CW16 and the like, it can be seen that the actual state can be accurately reproduced to the extent that it can be recognized that FIG. 20 (a) and FIG. 20 (b) correspond to each other. Although the shape of the zebra zone ZZ16 is different from the actual state, the correspondence between FIG. 20A and FIG. 20B is relatively easy because the zebra zone ZZ16 is drawn at this position. Can be recognized.
Thus, according to the present embodiment, it is possible to reproduce road markings with an accuracy sufficient for the purpose of intuitively recognizing the correspondence between each actual point and the map. According to the present embodiment, there is an advantage that road marking data for drawing such a road marking can be generated with a light processing load.

F. Effects and variations:
According to the route guidance system 10 of the embodiment described above, since it is possible to provide an enlarged view of the intersection that reproduces the road marking, the reality of the intersection is improved, and the user can intuitively understand the actual intersection and the intersection that is being guided. Can be associated with each other. In addition, since the route guidance system 10 does not need to prepare an enlarged view of the intersection as image data in advance, such display can be realized with a small data capacity.
Furthermore, in the road marking of the embodiment, the traveling direction arrow of each lane is also displayed, and the next intersection display (FIG. 8) and the default display also guide the previous guidance intersection, thereby improving the safety of user traffic. Is also possible.

  Although the embodiments of the present invention have been described above, the various processes described in the above-described embodiments are not necessarily all provided, and some of them may be omitted or replaced with other processes. I do not care. In the above-described example, the process executed in software may be executed in hardware and vice versa.

  The present invention can be used for route guidance that provides an enlarged view depicting road markings.

DESCRIPTION OF SYMBOLS 10 ... Route guidance system 11 ... Main control part 12 ... Command input part 13 ... Current position specific | specification part 14 ... Route search part 15 ... Route guidance part 16 ... Guidance display control part 20 ... Map database 21 ... Road network database 22 ... Drawing database DESCRIPTION OF SYMBOLS 30 ... Road marking display part 31 ... Road network grouping process part 32 ... Intersection area | region setting part 34 ... Crosswalk processing part 36 ... Road white line data generation part 38 ... Traveling direction arrow data generation part 40 ... Road marking prescription | regulation database

Claims (8)

A route guidance system for displaying a map and guiding a route,
A road network database for storing road network data representing roads by nodes and links;
Based on the road network database, a route search unit for searching for a route from a specified departure place to a destination;
A drawing database that stores map polygon data for drawing roads;
Including lane width, line width, and line length in case of broken line for vehicle lane boundary line , white line width in the current basin, distance between white lines in the current basin, stop line width, distance between pedestrian crossings and stop lines, stop Stores road marking regulation data that prescribes the shape and position of road markings, including at least a part of the banned line change prohibition line, pedestrian crossing line width, pedestrian crossing line interval, and direction arrow direction, as common parameters based on laws and regulations. A road marking regulation database,
For the searched route, a guidance branch point to be a route guidance target is specified, and the vehicle traffic band with respect to the map including the route based on the map polygon data, the road network data, and the road marking regulation data An enlarged view in which the guide branch point is enlarged to the extent that a boundary line can be drawn is generated, and a vehicle traffic band for the guide branch point is generated in the enlarged view according to the shape of the guide branch point based on the road marking regulation data A route guidance system comprising: a route guidance unit that dynamically draws a road marking including a boundary line and displays the enlarged view to guide the route. The route guidance system according to claim 1,
The route guidance unit linearizes the shape of the link in the area of the guidance branch point and draws the vehicle lane boundary line. The route guidance system according to claim 1 or 2,
The route guidance unit
Select a plurality of guidance branch points to be provided as the enlarged view,
A route guidance system that displays a plurality of enlarged views in a list that can be listed in order along the route. A route guidance system according to claim 3,
The route guidance unit
Display the map and the enlarged view side by side,
In the enlarged view, the shape of the link between the plurality of guide branch points is linearized, and the enlarged view of the plurality of guide branch points is linearly connected with the road between the guide branch points without being separated . A route guidance system that displays deformation . The route guidance system according to claim 3 or 4,
The route guidance unit
A route guidance system that arranges and displays each enlarged map so that an interval between the enlarged maps corresponds to a distance between corresponding guide branch points. A route guidance system according to any one of claims 1 to 5,
The road marking regulation database also stores data for defining the shape and position of the direction arrow to be drawn in each lane,
The route guidance unit
A route guidance system for displaying the enlarged view depicting the traveling direction arrow based on the road marking regulation database. A route guidance method for guiding a route by displaying a map using a computer,
The computer
A road network database for storing road network data representing roads by nodes and links;
A drawing database that stores map polygon data for drawing roads;
Including lane width, line width, and line length in case of broken line for vehicle lane boundary line , white line width in the current basin, distance between white lines in the current lane, stop line width, distance between pedestrian crossings and stop lines, stop Stores road marking regulation data that prescribes the shape and position of road markings, including at least a part of the banned line change prohibition line, pedestrian crossing line width, pedestrian crossing line interval, and direction arrow direction, as common parameters based on laws and regulations. And a road marking regulation database
The route guidance method is:
Searching for a route from a designated departure point to a destination based on the road network database;
Identifying a guidance branch point to be a route guidance target for the searched route;
Based on the map polygon data, the road network data, and the road marking regulation data, an enlarged view in which the guidance branch point is enlarged to the extent that the vehicle traffic zone boundary line can be drawn on a map including a route is generated , and the enlarged view is generated. In the figure, dynamically drawing a road marking including a vehicle traffic band boundary line for the guidance branch point according to the shape of the guidance branch point based on the road marking regulation data ;
A route guidance method comprising: displaying the enlarged view and guiding the route. A computer program for displaying a map and guiding a route by a computer,
The computer
A road network database for storing road network data representing roads by nodes and links;
A drawing database that stores map polygon data for drawing roads;
Including lane width, line width, and line length in case of broken line for vehicle lane boundary line , white line width in the current basin, distance between white lines in the current basin, stop line width, distance between pedestrian crossings and stop lines, stop Stores road marking regulation data that prescribes the shape and position of road markings, including at least a part of the banned line change prohibition line, pedestrian crossing line width, pedestrian crossing line interval, and direction arrow direction, as common parameters based on laws and regulations. And a road marking regulation database
The computer program is
A function of searching for a route from a specified departure place to a destination based on the road network database;
A function for specifying a guidance branch point to be a route guidance target for the searched route;
Based on the map polygon data, the road network data, and the road marking regulation data, an enlarged view in which the guidance branch point is enlarged to the extent that the vehicle traffic zone boundary line can be drawn on a map including a route is generated , and the enlarged view is generated. In the figure, a function of dynamically drawing a road marking including a vehicle lane boundary line for the guidance branch point according to the shape of the guidance branch point based on the road marking regulation data ;
A computer program for causing a computer to realize the function of displaying the enlarged view and guiding the route.