JPH11132784A - Map display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a map display device which automatically changes a crossing enlarged map displayed on a map into such a reduction as being suited to the actual route guidance. SOLUTION: When a guide crossing belongs to a traffic circle, it is so adjusted that the circle center is set to the center of a screen display and the whole traffic circle is put in the screen display region and displayed in a prescribed size or more. When the crossing circumference only is enlargedly displayed in the guide crossing belonging to the traffic circle, only a part of the traffic circle is displayed so that after entering, a driver may not recognize how ahead retreating path he should turn. If the whole traffic circle is enlargedly displayed in an appropriate size, a user who looks the enlarged map understands the relative positional relation of the retreating path in the whole traffic circle so that the user can drive while recognizing how ahead retreating path he should turn after entering on the ring route.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a map display device, and more particularly to a map display device having a so-called intersection enlargement function for enlarging and displaying a branch point to be guided.

[0002]

2. Description of the Related Art There is known a navigation system which detects a position by a GPS or the like as a vehicle travels, and displays the position together with a road map on a display to smoothly reach a destination.

[0003] Further, there is also known a navigation system which calculates and obtains an appropriate route from a current position to a destination and uses it as a guide, which contributes to a smoother driving. In such a case, the conventional map display device usually displays a route guide from the current location to the destination on a map displaying the vicinity of the current location of the vehicle as route guidance. In the display method, the color of the guidance route is changed to a normal road color to make it easier to see. Further, at a branch point (here, for example, an intersection) where a turn should be made on the guidance route, an enlarged view of the intersection is displayed so that the driver can more accurately grasp the intersection where the turn is to be made next. In this enlarged view of the intersection, the intersection and its surrounding map are enlarged and displayed on the screen. For example, the map data is drawn at a fixed scale such as a scale of 1/500, and is enlarged and displayed on the display. .

[0004]

[0005] By the way, one of the road systems often seen mainly in Europe and the United States is a traffic circle (circular intersection, rotary or rounda).
Also called bout. ). As shown in FIGS. 8 (a) and 8 (c), for example, this traffic circle is formed by connecting a plurality of approach roads and a plurality of egress roads to a closed ring-shaped path, and its size. (Eg, the maximum diameter of the annular path) may vary.

[0005] For example, a traffic circle shown in FIG. 8A has a relatively small annular path portion. If this is enlarged and displayed at a conventional fixed scale, the line may be broken and the details of the traffic circle may not be discriminated as shown in FIG.

On the other hand, the traffic circle shown in FIG. 8 (c) has a relatively large annular path portion. When this is enlarged and displayed at a conventional fixed scale, in this case, FIG.
As shown in FIG. 8B, the line is not broken and the details of the traffic circle cannot be determined. However, as shown in FIG. 8D, only a part of the traffic circle may be displayed. This is because the connection between the circular route and the exit road of the traffic circle is regarded as an intersection,
This is because only the surrounding area is displayed. However, when traveling on a traffic circle, it is necessary to recognize how many exit roads should be made after entering the annular route before traveling. That is, there is a possibility that it is not possible to determine which exit road to exit unless the relative positional relationship in the entire traffic circle is grasped, not just the exit road.

[0007] A similar problem also occurs in a loop-shaped connecting road from a ground road to an elevated road in a grade separation structure.
For example, it is a so-called rampway that passes when traveling from a general road that is a “highway” to a highway that is a “flyover” (or a freeway found in Western countries).

For example, the loop-shaped connecting path shown in FIG. 11A has a relatively large loop-shaped portion. When this is enlarged and displayed at a conventional fixed scale, only a part of the loop shape may be displayed as shown in FIG. This is because the part of the overpass is not considered as an intersection between ordinary roads because it does not actually allow vehicles to pass through, and it is displayed only as a diagonal branch at the intrusion into the loop connection road That's why. However, for the driver who wants to proceed to the route connecting to the elevated road, FIG.
It may not be possible to determine whether the diagonal branch displayed as in (b) is a loop-shaped connection,
Eventually, it becomes difficult to know which branch to turn.

The term "loop-shaped connecting road" as used herein refers to the angle of intrusion into the connecting road among the connecting roads connecting the ordinary roads that are "ground roads" with the expressways and freeways that are "overpasses". Indicates a loop shape having a difference of not less than a predetermined angle. The predetermined angle serving as the condition of the "loop-shaped connection path" may be, for example, about 180 degrees. This is because if the angle is changed by about 180 degrees or more, the possibility that the oblique branch displayed as shown in FIG. Therefore, even if it is less than 180 deg, if it has a shape that causes the above-described problem, it can be regarded as a loop-shaped connection path.

[0010] Further, such a problem must be considered not only for the traffic circle and the loop-shaped connection road described above but also for a complicated intersection. For example,
A road with a small width and a road with a large width intersect at a “diagonal T intersection” or “diagonal crossing”, and a large road including such an intersection at a “diagonal cross intersection”. The situation is such that they cross in an area of about 100 m in a complicated manner. In this case, because there are multiple intersections and diagonal intersections, the color of the guidance route is changed to the normal road color, and even if the corresponding intersection part is enlarged and displayed, it is actually near that intersection. When traveling, it is difficult to grasp an accurate traveling route. That is, there is a possibility that it is not possible to determine which of the roads where the guidance route intersects in a complicated manner in the above-described area having a radius of about 100 m.

Accordingly, an object of the present invention is to provide a map display device capable of automatically changing an enlarged view of an intersection displayed on a map to a scale suitable for actual route guidance.

[0012]

A map display device according to the present invention stores guidance route data connecting a departure point and a destination, which is set with reference to map data stored in advance. ing. During traveling, a map around the current location of the vehicle and a guidance route around the current location of the vehicle are extracted from the map data and the guidance route data, and the map including the current location surrounding map, the current location surrounding guidance route, and the vehicle current position mark are extracted. The image is displayed on the screen, and a predetermined route guidance is performed from the departure place to the destination. Further, when the vehicle approaches a branch point on the route to be guided, a map image including at least the current location surrounding map and the current location surrounding guidance route around the branch point is enlarged and displayed on the screen.

Under such a premise, the map display device of the present invention further provides that if the branch point to be guided belongs to a predetermined complex intersection area, the entire complex intersection area falls within the screen display area and Adjust so that it is displayed in the size of or more. The expression “more than a predetermined size” means that, for example, the maximum straight-line distance in the complex intersection area is half or more of the minimum display width of the screen display area. of course,
Although it may be larger or smaller than half, it is meaningless to enlarge and display if the size is not larger than a certain level.
It is preferable that it is about half or more.

As the complex intersection area to be adjusted, for example, a traffic circle can be considered. As described above, the traffic circle is configured by connecting a plurality of approach roads and a plurality of exit roads to the closed circular path (see FIG. 8), and the maximum diameter of the circular path varies. For example, the traffic circle shown in FIG. 8 (c) has a relatively large circular route portion, and when this is enlarged and displayed at a conventional fixed scale, in this case, as shown in FIG. Only a part may be displayed. This is because the connection between the circular route and the exit road of the traffic circle is regarded as an intersection, and only the surrounding area is displayed. However, when traveling on a traffic circle, it is necessary to recognize how many exit roads should be made after entering the annular route before traveling. That is, there is a possibility that it is not possible to determine which exit road to exit unless the relative positional relationship in the entire traffic circle is grasped, not just the exit road.

On the other hand, according to the map display device of the present invention, when the guidance junction belongs to the traffic circle, the display does not include the guidance junction but includes the guidance junction. Displaying the entire traffic circle in an appropriate size "can be realized. Therefore, the user who sees the enlarged map understands the relative positional relationship of the exit routes in the whole traffic circle, etc., and recognizes how many exit routes after entering the circular route should be turned. Will be able to run.

As a complicated intersection area to be adjusted, a loop-shaped connecting road can be considered. The loop connection path is
As described above, when traveling from an underground road to an elevated road, the connecting path is a loop-shaped connecting path that connects them, and the size of the loop shape varies. For example, the loop-shaped connecting path shown in FIG. 11A has a relatively large loop-shaped portion, and when this is enlarged and displayed on a conventional fixed scale, FIG.
In some cases, only a part of the loop shape is displayed as shown in FIG. In this way, when the display is displayed only as a diagonal branch at the intrusion into the loop-shaped connection road, for the driver who wants to proceed to the path connected to the elevated road, the displayed diagonal branch is fulfilled at the loop-shaped connection road. There is a possibility that it may not be possible to determine whether or not there is, and after all, it becomes difficult to determine which branch to turn.

On the other hand, according to the map display device of the present invention, when the guidance junction belongs to the loop-shaped connecting road,
Instead of "displaying around the guidance junction",
It is possible to realize an enlarged display from the viewpoint of "displaying the entire loop-shaped connecting road including the guide junction at an appropriate size". Therefore, the user who saw the enlarged map can confirm that the displayed loop-shaped connecting road connects to the elevated road that he / she wants to go to, and confidently determine that the user should turn at the displayed diagonal branch. You can do it.

As described above, the enlarged view of the intersection displayed on the map can be automatically changed to a scale suitable for actual route guidance. In addition, from the viewpoint of displaying the entire traffic circle and the entire loop-shaped connection road with an appropriate size, it is also preferable that the center of the traffic circle as the complex intersection area be the center of the screen display. .

The complex intersection area to be adjusted includes:
Not only traffic circles, but also complex intersections. For example, a road having a small width and a road having a large width intersect at a “diagonal T intersection” or “diagonal intersection”, and a road having a large width including such an intersection “diagonally crosses” to form a plurality of roads. Intersect in an area with a radius of about 100 m.
In this case, because there are multiple intersections and diagonal intersections, the color of the guidance route is changed to the normal road color, and even if the corresponding intersection part is enlarged and displayed, it is actually near that intersection. When traveling, it is difficult to grasp an accurate traveling route. That is, there is a possibility that it is not possible to determine which of the roads where the guidance route intersects in a complicated manner in the above-described area having a radius of about 100 m.

Therefore, also in this case, it is possible to realize an enlarged display from the viewpoint of "displaying the entire complex intersection area in an appropriate size" in units of a predetermined area regarded as the complicated intersection. Therefore, the user who has viewed the enlarged map can easily grasp the exit route or the like in the set guidance route from the complicated intersecting road conditions. Also in this case, it is preferable that the center of the complex intersection area be the screen display center.

When the map image around the guidance junction is displayed on an enlarged screen as described above, a plurality of map data representing predetermined areas at different scales are stored, and the map data of the minimum scale among the plurality of map data is stored. It is conceivable to use the map image enlarged display around the junction. In such a situation, when the guidance junction belongs to a predetermined complicated intersection area, the map image using the map data of the minimum scale is enlarged or reduced, and the entire complex intersection area is displayed in the screen display area. What is necessary is just to make it fit and to be displayed in a predetermined size or more.

When a traffic circle is assumed as a complex intersection area, the following is also preferable. In other words, the traffic circle attribute is set to the nodes and links constituting the traffic circle, and if the node indicating the guidance branch point has the traffic circle attribute, it is determined that the guidance branch point belongs to the traffic circle. Further, starting from a link including the node indicating the guidance branch point and having the traffic circle attribute, the search is sequentially performed until the link having the traffic circle attribute goes around once, and the traffic circle obtained by the search is used for the traffic circle. To understand the shape and the like.

On the other hand, when a loop-shaped connecting road is assumed as a complicated intersection area, the following is also preferable.
That is, if a node indicating a branch point to be guided has a loop connection attribute, the guidance branch point is set to a predetermined complicated intersection area. Is determined to belong to the loop-shaped connection path. In addition, starting from a link including the node indicating the guidance branch point and having a loop-shaped connection path attribute, a link having a loop-shaped connection path attribute is sequentially searched to the end, and the search is performed from the start point to the end. Ascertain the shape of the loop-shaped connection path using links.

In this way, it is not necessary to separately store the data indicating the area where the traffic circle or the loop connection exists, the shape data of the traffic circle or the loop connection in the map data. .
That is, it can be generated from node and link data when needed. This is also advantageous in that the amount of map data is not increased.

On the other hand, when the complex intersection area is displayed on the screen with an appropriate size, for example, it is conceivable that the maximum width of the complex intersection area is about half the display area width.
When the complicated intersection area is a traffic circle or a loop-shaped connecting road, the traffic circle is determined based on the maximum straight-line distance of the traffic circle and the size of the screen display area. The map image is enlarged and displayed on the screen so that the circle or the loop-shaped connecting road falls within the screen display area and is displayed with a predetermined size or more.

The maximum straight line distance in the case of a traffic circle is the maximum diameter. The reason why the maximum diameter is adopted in this way is that, for example, in the case of an elliptical shape, the major diameter must fit within the screen display area. In that sense, when the screen display area is rectangular, it is necessary to adopt the shorter display width. On the other hand, the maximum straight-line distance in the case of a loop-shaped connecting path is literally the distance between two points that are most separated in the overall shape.

The traffic circle shown in FIG. 8 (a) has a relatively small annular route.
As described above, when this is enlarged and displayed at a conventional fixed scale, the line may be broken as shown in FIG. 8B and the details of the traffic circle may not be discriminated due to the relationship of the link width to be drawn. A similar situation can be assumed for a loop-shaped connecting path.

In order to cope with such a situation, claim 9
As shown in the above, if the complicated intersection area is a traffic circle or a loop-shaped connecting road, and the map image is enlarged and displayed on the screen with a normal line width, the inside of the traffic circle or the loop-shaped connecting road is collapsed. What is necessary is just to reduce the line width when performing. However, if the screen is not visible when the screen is displayed with the reduced line width, it is preferable to display the screen with a preset minimum visible line width.

With respect to the display position of the complex intersection area, for example, it is conceivable that the screen is displayed such that the approach route to the complex intersection area is located near the lower end of the display area. In this way, the guidance route is displayed from the approach route near the lower end of the display area to the vicinity of the center of the display area, which matches the user's feeling based on the traveling direction of the vehicle.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. It is needless to say that the embodiments of the present invention are not limited to the following examples, and can take various forms as long as they belong to the technical scope of the present invention. [First Embodiment] FIG. 1 is a block diagram showing the overall configuration of an on-vehicle map display device 2 as an embodiment. The on-vehicle map display device 2 includes a position detector 4, a map data input device 6, an operation switch group 8, a control unit 10 connected thereto, an external memory 12 connected to the control unit 10, a display 14, and a remote controller. The sensor 15 is provided. The control unit 10 is configured as a normal computer, and includes a C
A PU, a ROM, a RAM, an I / O, and a bus line for connecting these components are provided.

The position detector 4 includes a well-known geomagnetic sensor 16, a gyroscope 18, and a distance sensor 2.
0, and GP for Global Positioning System (GPS) that detects the position of the vehicle based on radio waves from satellites
It has an S receiver 22. These sensors, etc.
Each of 8, 20, and 22 has an error having a different property, and is configured to be used while being interpolated by a plurality of sensors. It should be noted that depending on the accuracy, a part of the above-described components may be used, and a rotation sensor for the steering wheel, a wheel sensor for each rolling wheel, or the like may be used.

The map data input device 6 is a device for inputting various data including so-called map matching data for improving the accuracy of position detection, map data, and facility data described later. As a storage medium, a CD-ROM is generally used because of its data amount, but another medium such as a DVD or a memory card may be used.

The map data is formed by connecting a plurality of nodes such as intersections with links to form a map. For each link, a unique number (link ID) for specifying the link, the length of the link , The X and Y coordinates of the start and end of the link, the road width of the link, and the link information including the data of the road type (indicating road information such as a toll road) are stored. The configuration of the map data using the link information and the like is the same as the conventional one. However, in the case of the present embodiment, in order to display maps of different scales on the display unit 14, for example, a plurality of maps representing a predetermined area at eight kinds of scales are stored. The smallest scale (for example, 1/4000) of these is used for intersection enlargement. However, in this embodiment, this 4
1 / 500th using 1 / 000th scale map
Make a considerable enlargement. Then, the enlarged map equivalent to 1/500 is drawn by further scaling it to an arbitrary scale.
It can be displayed.

The position detector 4, the map data input device 6, the operation switch group 8, the control section 10, the display 14, the remote control sensor 15, and the like constitute a so-called navigation device. The screen of the display 14 includes a vehicle current position mark (described later) input from the position detector 4 and a map data input device 6.
The input map data and additional data such as a guide route, a name, and a mark to be displayed on the map can be displayed in a superimposed manner.

The on-vehicle map display device 2 is a remote control terminal (hereinafter, referred to as a remote controller) 15.
When the position of the destination and the designation of a specific route such as an expressway (that is, the designation of a passing point) are input from the remote control sensor 15 or the operation switch group 8 via a, the destination is changed from the current location to the destination. It also has a so-called route guidance function of automatically selecting the optimal route up to and forming and displaying a guidance route. As a technique for automatically setting the optimum route, a technique such as the Dijkstra method is known. As the operation switch group 8, for example, a touch switch or a mechanical switch integrated with the display 14 is used, and is used for various inputs. Note that the setting and display of the guide route is not a main feature of the present invention, and a detailed description thereof will be omitted.

The processing executed by the control unit 10 is shown in FIG.
Is shown in the flowchart of FIG. Here, the guidance route setting process, the present location surrounding map display process, and the intersection enlarged view display process are mainly shown. When the power switch of the on-vehicle map display device 2 is turned on, the process of FIG. 2 starts after predetermined initial settings.

First, a current location calculation process (S100) is performed. Here, the current position of the vehicle is calculated based on a signal from the position detector 4. Next, it is determined whether or not guidance is being performed (S110). That is, it is determined whether or not a mode for displaying route guidance (here, intersection guidance) to the destination by a driver's setting operation (hereinafter, referred to as a guidance display mode) is set. If it is not the guidance display mode (S110: NO), the display processing of the map around the current location (S1)
20) is the CD set in the map data input device 6
-It is performed by reading the map data of the corresponding area from the ROM.

Next, it is determined whether a destination setting operation has been performed (S130). If the destination setting operation has not been performed (S130: NO), the process returns to the current position calculation processing in step S100. Therefore, it is not being guided (S1
10: NO) and if the destination setting operation has not been performed (S130: NO), the display of the map around the current position according to the movement of the vehicle (S120) is repeated.

Next, when the driver performs a destination setting operation (S130: YES), a map around the destination input by the driver is displayed, and accurate position data of the destination is displayed in accordance with the driver's input. Acquisition and designation of a specific road as necessary are performed (S140). Next, the process waits for a route calculation start operation (S150). If the route calculation start operation is performed by the driver (S150: YES), the route calculation between the set destination and the current location is performed by link information in the map data. By using, for example, the Dijkstra method is used to calculate a route that minimizes the route cost from the current location to the destination via the passing point (S
160). Corresponding to the calculated route, the node ID indicating the position of the intersection and the link ID indicating the road connecting the position of the intersection are set in the map data input device 6 in C.
The control circuit 10 is extracted from the map data in the D-ROM.
Is stored in the work memory.

Next, it is determined whether or not the driver has performed a guidance start operation (S170). If there is no guidance start operation within a predetermined time (S170: NO), the process returns to step S100 and returns to the above-described step. S10
0, S110, S120, and S130 are repeated.

If there is a guidance start operation within a predetermined time (S1
70: YES), the process returns to step S110 to determine whether or not guidance is being performed. However, since the guidance start operation has been performed, “YES” is determined in step S110, and it is determined whether or not it is within Am before the guidance target intersection. Is performed (S180). The guidance target intersection means an intersection (hereinafter referred to as a route target intersection) extracted as a node ID in step S160, where the route is bent. Am is a distance of, for example, about 200 m or 400 m. If the guidance target intersection is not within Am (S180: NO), the process proceeds to step S120, and the process of displaying a map around the current location as usual is continued.

If the distance is within Am before the guidance target intersection, an intersection enlarged view display process (S200) is executed. This S
Details of the intersection enlarged view display processing at 200 will be described with reference to the flowchart of FIG. In this processing, the type of the next guidance intersection is acquired (S210), and it is determined whether or not the guidance intersection is a traffic circle (S220).
Since an ID indicating a traffic circle is set in the map data corresponding to the node ID, it can be determined whether or not the intersection is in the traffic circle by referring to the ID. In the case of the present embodiment, even if it is an intersection in a traffic circle, it does not correspond to entering the node, and it is determined that the guidance intersection is a traffic circle only when exiting from the node. Like that.

If the guidance intersection is not a traffic circle (S220: NO), the process proceeds to S290, where the scale is set to 1 and the target guidance intersection itself is set as the display center. In the case of an intersection enlargement, as described above, a map having a minimum scale (for example, 1/4000) of a plurality of maps representing a predetermined area at eight kinds of scales is used to obtain a map of 5 points.
An enlarged view equivalent to 1/1000 is shown. The enlarged map corresponding to the 1 / 500th of the map can be drawn and displayed at a further enlarged / reduced scale. The magnification of the 1 / 500th of the enlarged map is determined. It is this scale factor that determines

Therefore, in S280 to which the process proceeds after the processing of S290, the scale (1) set in S290 is set.
Times), draws a map with the guidance intersection at the display center. On the other hand, if the guidance intersection is a traffic circle (S220: YES), the process proceeds to S230, and node information having the attribute of the traffic circle including the guidance intersection is acquired.

The details of the node information acquisition processing in S230 will be described with reference to the flowchart shown in FIG.
Note that, in order to clarify the details of this processing, the description will be made on the premise of a traffic circle as shown in FIG. Therefore, first, data set for this traffic circle will be described.
In this traffic circle, the circular route has links L1 to L1.
Links L9 to L18 are provided for nodes N1 to N8, which are end nodes of the links L1 to L8, and serve as entrance and exit routes to and from inside and outside the traffic circle. It should be noted that the direction of passage of the annular route constituted by the links L1 to L8 is determined, and in the order of the links, for example, when L1 is the starting point, L1 → L2 → L3 →
It is a one-way street of L4 → L5 → L6 → L7 → L8.

Here, a detailed description will be given to which nodes the links L9 to L18 serving as entrance and exit routes to and from the traffic circle are connected. First, an ingress link L9 from outside the traffic circle is connected to the node N1.

An exit link L10 to the outside of the traffic circle and an ingress link L18 from inside the traffic circle are connected to the node N2, and an ingress link L11 and a traffic circle from outside the traffic circle to the node N3. Is connected to the exit link L17 to the inside.

The exit link L12 to the outside of the traffic circle is connected to the node N4.
Has an incoming link L1 from outside the traffic circle
3 are connected. An exit link L14 to the outside of the traffic circle and an ingress link L17 from the inside of the traffic circle are connected to the node N6.
The ingress link L15 from outside the traffic circle and the exit link L18 from inside the traffic circle are connected to the node N7.

The exit link L16 to the outside of the traffic circle is connected to the node N8. The above is the description of the data set in the prerequisite traffic circle, so the flowchart of FIG. 4 will be described next. This process is a process for acquiring information on nodes constituting a traffic circle based on a guidance intersection.

First step S in the flowchart of FIG.
At 2310, the initial values of the end node and the search node i are set. Here, a description is given assuming a route that exits from the node N6 via the link L14. In this case, the end node is the node N6, and the search node i is a node immediately before the end node on the set route. The end point node (N6) and the initial value (N5) of the search node i are stored in a storage area in the control unit 10.

Then, in subsequent S2320, it is determined whether or not the search node i matches the end node. If the search node i is the initial value (N5), the two nodes do not match (S2320: YES), and the flow shifts to S2330. In S2330, a link connected to the search node i is obtained. When the search node i = N5, there are three links L5, L6, and L13 to be connected as shown in FIG. However, in S2310, the node N5 connected to the end node N6 on the set route via the link L6 is set as the initial value of the search node i. As described above, the present processing routine is processing for acquiring node information constituting a traffic circle based on the guidance intersection, and thus the link L6 may be excluded from the candidates here. Therefore, when the search node i = N5, the link acquired in S2330 is L5, L13
One.

Then, in the following S2340, S2330
It is determined whether or not there is a link having a circle attribute among the links obtained in. Since an ID indicating a traffic circle is set in the map data corresponding to the link ID, it can be determined by referring to the ID.

If there is no link having the circle attribute (S2340: NO), the process is terminated. If there is a link having the circle attribute (S234).
0: YES), to S2350. Search node i =
In the case of N5, since there is a link L5 having a circle attribute, the flow shifts to S2350.

In S2350, the terminal node of the link having the circle attribute is obtained. In the case of link L5, the terminal node is N4. This terminal node N4 is
Is stored in the storage area. Then, the process returns to S2320, and this time, assuming that the search node i = N4, S2320 to S2
Step 350 is executed. As a result, in S2350,
N3, N2, N1, N8, and N7 are sequentially acquired as end nodes. Then, the link having the circle attribute connected to the node N7 is L7, and the end node N6 of the link L7 matches the end node, so a negative determination is made in S2320, and the present processing routine is terminated and FIG.
To S240.

In S240 of FIG. 3, the maximum value Xmax and the minimum value X of the X-axis of the coordinates forming the traffic circle using the node information of the circle attribute acquired in S230.
The maximum value Ymax and the minimum value Ymin of the min and Y axes are obtained. Specifically, in the case of the traffic circle shown in FIG. 7, the coordinates (Xn, Yn) (n) in the map data of the eight nodes N1 to N8 constituting the traffic circle
= 1 to 8) to obtain the maximum value and the minimum value of each of the X axis and the Y axis.

At S250, the maximum value Xmax and the minimum value Xmin of the X-axis acquired at S240 and the maximum value Ym of the Y-axis are obtained.
ax and the minimum value Ymin, the center coordinates (Xc, Y
c) is calculated by the following equation. Xc = (Xmax + Xmin) / 2 Yc = (Ymax + Ymin) / 2 Then, the center coordinates (Xc, Yc) are set as the display center when the traffic circle is displayed.

At S260, processing is performed to obtain a scale factor such that the traffic circle is displayed in an appropriate size for the display area of the display unit 14. This scale ratio acquisition processing will be described in detail with reference to the flowchart of FIG. In the first step 2610 of FIG.
The maximum diameter C is obtained using the maximum and minimum X, Y coordinates (Xmax, Xmin, Ymax, Ymin) of the traffic circle acquired at 240. Specifically, in FIG.
Assuming that the diameter in the axial direction is C1 and the diameter in the Y-axis direction is C2,
Since C1 = Xmax-Xmin and C2 = Ymax-Ymin, the larger one of C1 and C2 is defined as the maximum diameter C.
In the case shown in FIG. 7, since the diameter C1 in the X-axis direction is larger, C = C1.

At S2620, the length D1 on the map indicated by the horizontal display width of the display area of the display 14 and the length D2 indicated by the vertical display width on the map are D1> D.
2 is determined. As described above, in the case of intersection enlargement, a 1 / 500th enlarged map is used. Therefore, when the 1 / 500th enlarged map is used, the horizontal display width of the display area indicates the map width. Is D1, and the length on the map indicated by the vertical display width is D2.

When D1> D2, (S2
620: YES), and proceeds to S2630 to set the scale-ratio calculation display width D = (1/2) D2. This is D1> D
2 means that the display area has a horizontally long display area, so that the shortest vertical display width D2 is used as a reference, and the maximum diameter C of the traffic circle is about 1/2 of the vertical display width D2. (1/2)
It has been doubled.

On the other hand, if D1> D2 is not satisfied, that is, D1
If ≦ D2 (S2620: NO), the flow shifts to S2640 to set the scale-ratio calculation display width D = (1/2) D1. This means that since D1 ≦ D2 means that the display area is vertically long or the same in the horizontal and vertical directions, the shorter horizontal display width D1 is used as a reference.

After the scale width calculation display width D is obtained in S2630 or S2640, the flow shifts to S2650, where the scale ratio R is obtained by the following equation. R = C / (D · A) Here, A is a coefficient for increasing the precision. When the precision is not increased, the coefficient A is set to 1, and when the precision is increased, the coefficient A is set to a value larger than 1.

For example, D2 = 1000 m, C = 100 m
Then, the scale ratio R is calculated by setting A = 1. Display width D for scale calculation is (1/2) D2 and 500m
Therefore, R = 100 m / 500 m = 1/5.
Therefore, if the traffic circle (C = 100 m) is treated as a normal intersection, the traffic circle (C = 100 m) is only about one-tenth the vertical display width (1000 m) of the display area. If the traffic circle is displayed at ５ times, the traffic circle can be displayed with a size of about half of the vertical display width. For example, 50
Reduce the scale of a map with a scale of 0 to 1/5, that is, 100
Display in more detail on a scale of 1/100. Also,
Conversely, for example, let D2 = 1000 m, C = 2000 m, and further set A = 1 to calculate the scale R.
Since the scale width calculation display width D = 500 m, R = 20
00m / 500m = 4. Therefore, when treated as a normal intersection, the traffic circle (C = 100
m) is twice as large as the vertical display width (1000 m) of the display area, and the entire area cannot be displayed. However, if the map is displayed at a reduced scale of four times, the traffic circle becomes twice the vertical display width. The size can be reduced to about one-half. For example, the scale of a map with a scale of 1/500 is quadrupled,
In other words, the scale is reduced to 1/2000 and displayed as a wide-area map.

In the following S2660, it is determined whether or not the scale R is inappropriate, and if not, (S266)
0: YES), the scale ratio is set to R = 1, this processing routine is ended, and the routine goes to S270 in FIG. On the other hand, if the scale R obtained in S2650 is appropriate, the processing routine is terminated and the process proceeds to S270.

In S270 of FIG. 3, the width of the drawing line is determined. This drawing line width determination processing will be described in detail with reference to the flowchart of FIG. In the first step 2710 of FIG. 6, the maximum and minimum X, Y coordinates (Xmax, Xmin, Yma) of the traffic circle acquired in S240.
x, Ymin) to determine relative quantities △ X, △ Y. The relative amount in this case is ΔX = Xmax−Xmin, and ΔY = Y
max-Ymin.

Then, in S2720, it is determined whether or not the default line width is larger than the relative amounts ΔX and ΔY.
If the default line width is larger than the relative amounts △ X and △ Y (S2720: YES), the line width as it is will collapse the inside of the traffic circle, so the line width is reduced in the processing after S2730. Specifically, S273
At 0, the smaller of the relative amounts △ X and △ Y is substituted for で L,
In subsequent S2740, the line width is set to ΔL−α. Thereby, since the interval of α is secured inside the traffic circle, the traffic circle can be prevented from being crushed.

However, when the line width is too small, there is a possibility that the image cannot be visually recognized when displayed. Therefore, S
At 2750, the line width set at S2740 (△ L−
It is determined whether α) is smaller than the minimum guaranteed value. The minimum guaranteed value is a minimum value of a line width at which a line can be visually recognized when displayed. If the line width (△ L−α) is smaller than the minimum guaranteed value (S2750: YES), the line width is changed to the minimum guaranteed value (S2760), and this processing routine ends, and the process proceeds to S280 in FIG. .

It should be noted that a negative determination is made in S2720 described above,
That is, when the default line width is equal to or less than the relative amounts △ X and △ Y (S2720: NO), or when a negative determination is made in S2750, that is, when the line width (△ L-α) is equal to or more than the minimum guarantee value (S2750: NO) ), The processing routine is terminated as it is, and the flow shifts to S280.

Therefore, in S280 to which the process proceeds after S270, the center coordinates (Xc, Yc) of the traffic circle set in S250 are set as the display center, and S26
Scale ratio R obtained at 0, and if necessary S270
Draw the map with the changed drawing line width.

As described above, according to the map display device 2 of the present embodiment, for a guidance intersection that is not a traffic circle, the target guidance intersection itself is displayed and centered.
For example, an enlarged map of, for example, a 1/500 scale for intersection enlargement is enlarged and displayed. On the other hand, when the guidance intersection belongs to the traffic circle, the center of the traffic circle is set as the screen display center, and the adjustment is made so that the entire traffic circle fits within the screen display area and is displayed in a predetermined size or more. The size of the traffic circle varies, and, for example, as shown in FIG. 8 (c), when the circular route portion is relatively large, if the enlarged map is displayed as it is using a 1/500 enlarged map for intersection enlargement as it is. In this case, only a part of the traffic circle may be displayed as shown in FIG. This is because the connection between the circular route and the exit road of the traffic circle is regarded as an intersection, and only the surrounding area is displayed. However, when traveling on a traffic circle, it is necessary to recognize how many exit roads should be made after entering the annular route before traveling.
That is, there is a possibility that it is not possible to determine which exit road to exit unless the relative positional relationship in the entire traffic circle is grasped, not just the exit road.

On the other hand, according to the present map display device 2,
Instead of "displaying around the guidance intersection",
An enlarged display is performed from the viewpoint of “displaying the entire traffic circle including the guidance intersection at an appropriate size”. Therefore, the user who sees the enlarged map understands the relative positional relationship of the exit routes in the whole traffic circle, etc., and recognizes how many exit routes after entering the circular route should be turned. Will be able to run. In this way, the enlarged view of the intersection displayed on the map can be automatically changed to a scale suitable for actual route guidance.

The traffic circle shown in FIG. 8 (a) has a relatively small circular route portion. If the traffic circle is enlarged and displayed as it is using a 1 / 500th enlarged map for enlarging an intersection, As described above, as shown in FIG. 8B, the line may be broken and the details of the traffic circle may not be determined. Against this problem, the map display device 2 reduces the line width at the time of displaying the map image with a normal line width when the inside of the traffic circle is crushed when the screen image is displayed on the screen. (S2740 in FIG. 6). However, in the case where it is impossible to visually recognize the screen when the screen is displayed with the reduced line width, the screen is displayed with the preset line width of the minimum guarantee value that can be visually recognized (S2750 and S2760 in FIG. 6). ). [Second Embodiment] In the above-described first embodiment, a case where a traffic circle is considered as a complicated intersection area has been described. In this second embodiment, a case where a loop-shaped connection road is considered as a complex intersection area will be described. I do. The overall configuration of the in-vehicle map display device 2 and mainly the guide route setting process and the present location surrounding map display process executed by the control unit 10 are the same as those of the first embodiment shown in FIGS. Since this is the same as the case, the description will not be repeated here.

Therefore, among the processes executed by the control unit 10, an intersection enlarged view display process different from that of the first embodiment will be described with reference to FIG. In the intersection enlarged view display processing shown in FIG. 9, first, the link type is acquired (S301).
0), it is determined whether or not the link type is a connection road (S3020). The connecting road is a road connecting the ground road to the elevated road as described above, and is called a rampway or the like. Here, it does not matter whether the connection path is loop-shaped or not. That is, in the map data, an ID indicating that all roads connecting the ground road and the elevated road are connection roads is set, and the determination is made with reference to the ID.

If the target link is a connecting road (S3020: YES), all link shape points forming the connecting road are acquired (S3030). Then, the starting point coordinate Si of the exit link is obtained (S3040), and the next shape point coordinate Si + 1 is obtained (S3050), and the azimuth vector from the starting point coordinate Si to the next shape point coordinate Si + 1 is obtained. (S3060).

If it is the starting point of the loop-shaped connecting road (S
3070: YES), and sets the azimuth vector acquired in S3060 as an initial azimuth (S3080), and S3120.
Move to. In S3120, it is determined whether or not all the link shape points acquired in S3030 have been processed to the last. If not the last (S3120: NO),
It returns to S3050.

On the other hand, if it is not the start point (S3070: N
O), the difference between the initial azimuth set in S3080 and the azimuth vector acquired in S3060, that is, the current azimuth is 180
It is determined whether it is not less than deg. 180 misdirection
If it is not less than deg (S3090: YES), a flag (flg) is set (S3100), and then S3
Move to 110. If the azimuth difference is less than 180 deg (S3090: NO), the process directly proceeds to S3110.

In S3110, the maximum distance between the coordinates of the shape points is registered. This process is to search for and register the combination having the largest distance among the combinations between all the shape points obtained so far. After the processing of S3110, S3
Move to 120. In this way, after the processing of S3030 to S3120 is repeatedly performed for the link path in link units (S3120: YES), the process proceeds to the next link (S3130) and returns to S3010.

Note that even if there is substantially one connection road, the map data may be set to include a plurality of links. Therefore, the process proceeds to the next link in S3130. The link type acquired again in S3010 may become a connecting road again (S3020: Y
ES). In that case, the processing of S3030 and subsequent steps are repeatedly performed.

If the link type obtained in S3010 is not a connection road (S3020: NO), S3
The routine proceeds to 140, where it is determined whether the flag (flg) is set. As described above, the flag (flg) is set when the azimuth difference from the initial azimuth is 180 deg or more. Therefore, when the flag (flg) is set, it can be said that the road is a loop-shaped connection path. . On the other hand, if the flag (flg) is not set, it can be said that the road is not a connecting road, or even if it is a connecting road, it is "not in a loop". That is, assuming that the road is a connecting road (S3020: YES),
Even if the process of 3120 is executed, if the azimuth difference from the initial azimuth of the entire connection road is less than 180 deg, it is not determined that the connection road is a “loop connection road”.

Therefore, when the flag (flg) is set (S3140: YES), the center coordinates of the loop-shaped connecting road are set as the display center (S3150). For the center coordinates, the same method as that of the traffic circle of the first embodiment described above can be adopted. That is,
The maximum value Xmax and the minimum value Xmin of the X coordinate and the maximum value Ymax and the minimum value Ymin of the Y coordinate that constitute the loop-shaped connection path are obtained, and the center coordinates (Xc, Yc) are calculated by the following equation, for example.

Xc = (Xmax + Xmin) / 2, Yc = (Y
max + Ymin) / 2 In subsequent S3160, a scale is determined based on the maximum distance registered in S3110. The processing related to the determination of the scale is the same as the determination of the scale using the maximum diameter C in the case of the traffic circle of the first embodiment described above. That is, the maximum distance was used instead of the maximum diameter C. This is because the concept of the diameter can be applied in the case of a traffic circle because it is annular, but the concept of the maximum distance is applied because it is not annular in the case of a loop connection.

Then, a map is drawn according to the scale determined in S3160 and the display center obtained in S3150 (S3170). The outline of the drawn map is shown in FIG.
Shown in The entire loop-shaped connection path is within the display screen. On the other hand, when the flag (flg) is not set (S3040: NO), the guidance intersection is set as the display center (S3180), and the scale is set to 1 (S319).
0). Therefore, S3 is shifted to after the process of S3190.
At 170, a map at a scale of 1 is drawn with the guidance intersection as the display center.

As described above, in the case of the second embodiment, when the guidance intersection belongs to a loop-shaped connecting road, the center of the loop-shaped connecting road is used as the screen display center, and the entire loop-shaped connecting road is displayed on the screen. An adjustment is made so that the image is displayed within a predetermined area and within a predetermined size. The size of the loop shape of the loop-shaped connecting path varies, and for example, the loop-shaped connecting path shown in FIG. 11A has a relatively large loop-shaped portion, which is enlarged and displayed at a conventional fixed scale. Then, as shown in FIG. 11B, only a part of the loop shape may be displayed. In this way, when the display is displayed only as a diagonal branch at the intrusion into the loop-shaped connection road, for the driver who wants to proceed to the path connected to the elevated road, the displayed diagonal branch is fulfilled at the loop-shaped connection road. There is a possibility that it may not be possible to determine whether or not there is, and after all, it becomes difficult to determine which branch to turn.

On the other hand, in the case of the second embodiment, when the guidance intersection belongs to the loop-shaped connecting road, the viewpoint "displaying the periphery of the guidance intersection" is not used. Enlarged display from the viewpoint of "displaying the entire loop-shaped connection path with an appropriate size" can be realized. Therefore, a user who has viewed the enlarged map as illustrated in FIG. 10 can confirm that the displayed loop-shaped connection road is connected to an elevated road to which he / she wants to travel, and can turn at the displayed diagonal branch. You will be able to judge with confidence.

After the process of S3160 in FIG. 9, the first
As in the case of the traffic circle of the embodiment, the process of determining the width of the drawing line in S270 of FIG. 3 may be added. [Others] For example, in the above-described embodiment, a traffic circle or a loop-shaped connecting road is considered as an example of a complicated intersection area, but a complicated intersection may also be mentioned. For example, a road with a small width and a road with a large width are “diagonally T
Intersections "and" diagonal intersections ", and roads with a large width including such intersections" diagonal crossing ", and multiple roads intersect in an area with a radius of about 100m in a complicated manner. The situation. In this case, since there are a plurality of intersections and diagonal intersections, it is difficult to grasp an accurate traveling route when actually traveling near the intersection. That is, there is a possibility that it is not possible to determine which of the roads where the guidance route intersects in a complicated manner in the above-described area having a radius of about 100 m. Therefore, also in this case, it is possible to realize an enlarged display from the viewpoint of “displaying the entire complex intersection area in an appropriate size” in units of the predetermined area that is regarded as the complex intersection. for that reason,
A user who sees the enlarged map can easily grasp an exit route or the like in the set guidance route from the complicated intersecting road conditions. Also in this case, it is preferable that the center of the complex intersection area be the screen display center.

In the above embodiment, the scale R is set to R in step S2650 of the scale acquisition process shown in FIG.
= C / (DA), and the maximum diameter C used for this is the larger one of the diameter C1 in the X-axis direction and the diameter C2 in the Y-axis direction (S2610), and is displayed for scale reduction calculation. The width D is the smaller one of (1/2) D2 and (1/2) D1 (S2630, S2640). This is for the purpose of, for example, in the case of a rectangular display area, to make the maximum diameter of the traffic circle about half the display width of the shorter one. Of course, if it is desired that the maximum diameter C of the traffic circle is about one third of the display width D, the coefficients multiplied by D2 and D1 in S2630 and S2640 may be set to (1/3), If it is desired to be about three-fifths, (3/5) may be used.

Further, as the complex intersection area, the traffic circle in the first embodiment and the loop-shaped connection road in the second embodiment are individually taken, but of course, both may be processed. That is, in the intersection enlarged view display processing, the corresponding processing in FIG. 3 is executed for a traffic circle, and the corresponding processing in FIG. 9 is executed for a connecting road. What is necessary is just to display based on a reduced scale and a display center.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of an on-vehicle map display device according to an embodiment.

FIG. 2 is a flowchart illustrating a process executed by a control unit according to the embodiment.

FIG. 3 is a flowchart illustrating an intersection enlarged view display process of the first embodiment.

FIG. 4 is a flowchart illustrating a node information acquisition process according to the first embodiment.

FIG. 5 is a flowchart illustrating a scale ratio acquisition process according to the first embodiment.

FIG. 6 is a flowchart illustrating a drawing line width determination process according to the first embodiment.

FIG. 7 is an explanatory diagram of route data set for a traffic circle, the size of a traffic circle, the size of a display area, and the like.

FIG. 8 is an explanatory diagram showing a display example of a traffic circle by a conventional intersection enlarging process.

FIG. 9 is a flowchart illustrating an intersection enlarged view display process according to the second embodiment.

FIG. 10 is an explanatory diagram showing an outline of a loop-shaped connecting road displayed in the intersection enlarged view display processing of the second embodiment.

FIG. 11 is an explanatory diagram showing a display example of a loop-shaped connecting road by a conventional intersection enlarging process.

[Explanation of symbols]

 2 ... on-board map display device 4 ... position detector 6 ... map data input device 8 ... operation switch group 10 ... control unit 12 ... external memory 14 ... display device 15 ... remote control sensor 15 a ... remote control 16 ... geomagnetic sensor 18 ... gyroscope 20: distance sensor 22: GPS receiver

Claims (11)

[Claims] 1. A method according to claim 1, further comprising: storing guidance route data connecting the departure point to the destination, which is set with reference to map data stored in advance, and selecting from the map data and the guidance route data during traveling. A map around the current location of the vehicle and a guidance route around the current location of the vehicle are extracted, and a map image including the current location around map, the current location around the guidance route and the vehicle current position mark is displayed on the screen, and the departure point to the destination Perform a predetermined route guidance to, further, when approaching a branch point to be guided present on the route, magnify a map image including at least the current location surrounding map and the current location surrounding guidance route around the branch point In the map display device configured to display a screen, when the junction to be guided belongs to a predetermined complicated intersection area, the entire complex intersection area is included in the screen display area. Mari, and predetermined as represented by the magnitude or more, the map display device characterized by screen display by enlarging the map image. 2. A plurality of map data each representing a predetermined area on a different scale are stored, and the smallest one of the map data is used for enlarged display of a map image around the junction. If the branch point to be guided belongs to a predetermined complicated intersection area, the map image using the minimum scale map data is enlarged or reduced so that the entire complex intersection area fits in the screen display area and is The map display device according to claim 1, wherein the map is displayed in a size equal to or larger than. 3. A traffic circle is included as the complex intersection area.
2. The map display device according to 1. 4. A traffic circle attribute is set for the nodes and links constituting the traffic circle. If the node indicating the branch point to be guided has the traffic circle attribute, the guide branch point has a predetermined complicated intersection. It is determined that the link belongs to the traffic circle that is the area, and the link including the node indicating the guidance branch point and having the traffic circle attribute is set as a starting point, and the search is sequentially performed until the link having the traffic circle attribute is circled. 4. The map display device according to claim 3, wherein the shape of the traffic circle and the like are grasped by the link for one round. 5. The map display device according to claim 1, wherein the complex intersection area includes a loop-shaped connecting road from a ground road to an elevated road in a three-dimensional intersection structure. 6. A loop connection path attribute is set for each of the nodes and links constituting the loop connection path. If the node indicating the branch point to be guided has the loop connection path attribute, the guide branch is provided. It is determined that the point belongs to a loop-shaped connecting road that is a predetermined complicated intersection area, and links having a loop-shaped connecting road attribute sequentially including a node indicating the guidance junction and having a loop-shaped connecting road attribute are used as starting points. 6. The map display device according to claim 5, wherein the search is performed to the end, and the shape or the like of the loop-shaped connecting road is grasped by a link from the starting point to the end obtained by the search. 7. The screen display center according to claim 3, wherein when the complicated intersection area is a traffic circle or a loop-shaped connecting road, the center of the traffic circle or the loop-shaped connecting road is set as a screen display center. A map display device as described in Crab. 8. When the complicated intersection area is a traffic circle or a loop connection, the traffic circle or the loop is determined based on the maximum linear distance of the traffic circle or the loop connection and the size of the screen display area. The map display according to any one of claims 3 to 7, wherein the map image is enlarged and displayed on a screen so that the shape-connected road is displayed within a screen display area and is displayed at a predetermined size or more. apparatus. 9. When the complicated intersection area is a traffic circle or a loop-shaped connecting road, and when the map image is enlarged and displayed on a screen with a normal line width, the inside of the traffic circle or the loop-shaped connecting road is crushed. Reducing the line width at the time of the display.
8. The map display device according to any one of 8. 10. The screen display according to claim 9, wherein when the screen is not visible when the screen is displayed with the reduced line width, the screen is displayed with a preset minimum visible line width. Map display device. 11. The map display device according to claim 1, wherein a screen is displayed such that an approach route to the complex intersection area is located near a lower end of a display area.