JPH05281904A - Map display device for vehicle - Google Patents

Abstract

PURPOSE:To speedily extract and displays road information that a person on the vehicle requires from a road map data base by extracting road information in road kind units according to set display priority order. CONSTITUTION:Road map data on an area to be displayed which is set with input keys is read in a D-RAM 22 from a CD-ROM 16. The road map data stored in the D-RAM 22 are retrieved to extract object roads to be displayed according to the set display priority order and visibility evaluation criteria. The respective data on the extracted object roads to be displayed are converted from an earth coordinate system to the coordinate system of a display screen and developed as bit map data in a V-RAM 20, and a mark indicating the current position of the vehicle and the names of places, etc., are superimposed on the road map. Further, the bit map data in the V-RAM 20 are transferred to a CRT 18 through a graphic controller 19 to display the road map based upon the set display priority order and visibility evaluation criteria on the CRT 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle map display device for displaying a road map around a current position of a vehicle and guiding an occupant to a destination.

[0002]

2. Description of the Related Art A map display device for vehicles is known in which the display form of a road map is changed according to a set scale or density (see, for example, Japanese Patent Laid-Open No. 59-164583). This kind of map display device adds level information indicating what scale or density condition each road is to be displayed to the road map data stored in a storage medium, and sets from the road map data. Road information to which a level corresponding to the reduced scale or density is added is extracted and displayed on the display device.

[0003]

However, in the above-described vehicle map display device, since the road to be displayed is determined according to the scale or the display density of the display map, the road of the type required by the occupant is displayed. It may not be done. For example, when a map of a certain area is enlarged and displayed, even a narrow street that is not necessarily required by an occupant traveling on a national road is displayed in detail and the displayed map becomes difficult to see.
On the contrary, when a map of a certain area is reduced and displayed, only roads with high importance such as national roads are displayed, and necessary general roads are not displayed. Further, if the display density of the map is made coarse, only roads of high importance such as national roads are displayed, and necessary general roads are not displayed. On the other hand, if the display density is made fine, all roads such as highways, national roads, and prefectural roads that are not necessarily required by passengers traveling on the street are displayed, making the display map difficult to see.

Further, in the above vehicle map display device,
In order to extract the road information to which the corresponding level is added according to the set scale or display density, the search and extraction processing is performed for each individual road information, so the data search time and data extraction time are long and the display speed is slow. There is also a problem.

It is an object of the present invention to provide a vehicle map display device for quickly extracting and displaying road information required by an occupant from a road map database.

[0006]

The present invention will be described with reference to FIG. 1, which is a claim correspondence diagram, and the invention of claim 1 stores road map information of a data structure hierarchically classified by road type. A storage unit 100, a first setting unit 101 that sets a display priority order for each road type, and an extraction unit 102 that extracts road map information of a corresponding road type from the road map information according to the set display priority order.
And display means 103 for displaying the extracted road map information.
And to achieve the above object. The invention according to claim 2 further comprises second setting means 104 for setting the reference value of the road map information amount displayed on the display means 103, and the extracting means 102A stops the extraction when the road map information amount exceeds the reference value. It was done. Further, the invention of claim 3 is a detection means 105 for detecting a non-connected road from the road map information extracted by the extraction means 102, 102A.
And a connecting means 106 for connecting the unconnected roads based on the road map information stored in the storage means 100 when the detecting means 105 detects the unconnected roads. The connected roads are displayed in a display mode different from that of other roads.

[0007]

According to the vehicle map display device of the present invention, the road map information is extracted for each road type in accordance with the set display priority order from the road map information having a hierarchical data structure for each road type. Quickly display the required type of road map information. In the vehicle map display device according to the second aspect, the displayed road map information amount is limited to the reference value or less. In the vehicle map display device according to the third aspect, the unconnected roads are connected based on all the stored road map information, and are displayed in a display form different from other roads.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 2 and 3 are block diagrams showing the structure of a vehicle map display device according to an embodiment. As shown in the figure, this device is composed of a microcomputer centered on a CPU 1. The CPU 1 exchanges data with various devices via the system bus 2 to perform various arithmetic processes. A direction sensor 3 detects the traveling direction of the vehicle, and is connected to the system bus 2 via the amplifier 4, the A / D converter 5 and the I / O controller 6. Reference numeral 7 is a distance sensor that detects the traveling distance of the vehicle, and is connected to the system bus 2 via the I / O controller 6. 8
Is a key to input various commands and data to the device,
It is connected to the system bus 2 via the I / O controller 9. Reference numeral 10 is a voice output speaker, which is connected to the system bus 2 via the sound generator 11 and the I / O controller 9.

Reference numeral 12 is a position detection system (Global Positioning System) using a satellite.
m, hereinafter referred to as GPS) (hereinafter referred to as GPS receiver), and is connected to the system bus 2 via the extended I / O controller 13. The current position of the vehicle is detected based on the current position information from the GPS receiver 12, the traveling direction information of the vehicle from the azimuth sensor 3, and the traveling distance information from the distance sensor 7. Further, 14 is a receiver, which receives road traffic information and position information such as traffic congestion, road construction, traffic regulation, and the like via an antenna 15 from road beacons installed at roads and intersections.

Further, in FIG. 3, reference numeral 16 is a CD-ROM storing road map data, which is an interface S-ROM.
It is connected to the system bus 2 via the CSI controller 17. 18 is a VDT (Visual Display)
CRT that functions as y Terminal)
System bus 2 via graphic controller 19
Connected to and display a road map around the vehicle's current location.
Further, the system bus 2 has a VRT for image storage of the CRT 18.
A RAM 20, a ROM 21 for storing a control program described later, a D-RAM 22 for temporarily storing data, a Chinese character ROM 23, and a battery backup RAM 24 for storing information such as a current position when the ignition is off are connected.

Now, the road map data stored in the CD-ROM 16 will be described. Road map data is composed of road network data, name data such as place names, etc., and is divided and stored for each district. As shown in FIG. 4, each road in the road network data is configured as an aggregate of nodes (indicated by black circles in the figure) and links connecting the nodes, and each is represented using the earth coordinate system. Further, the link is composed of sub-links divided by interpolation points (or called bending points, which are indicated by white circles in the figure) provided for linear approximation of the road. In the road network shown in FIG. 4, # 1 to # 12 divided by nodes or interpolation points are sub-links, and, for example, # 3- # 4 connecting nodes are links. Further, as shown in FIG. 5, the nodes include intersection nodes (A, B, C, J), dead end nodes (F), dummy point nodes (E), and the like.

6 and 7 show the data structure of the road network data, FIG. 6 is data in which each road link is hierarchized according to the road type, and FIG. 7 is data in which each road link is hierarchized according to another road type. Is. The hierarchical levels of these road network data are designated to set the display priority for each road type. When the roads are selectively displayed according to the road type shown in FIG. 6, the hierarchy level 1 shown in FIG. 6 is set to the first display priority by the input key 8 and the second display hierarchy is set to the second display priority. Set level 6. Further, in order to make it easier to set the display priority, the display priority may be set interactively, such as "display a road with a width that almost passes the oncoming vehicle". Further, in the case of selectively displaying roads according to the road type shown in FIG. 7, for example, when it becomes necessary to drive on a highway, the hierarchical level 4 shown in FIG. 7 is set to the first display priority.

Next, in this embodiment, a visibility evaluation standard for evaluating the visibility of the displayed road map is set. This visibility evaluation standard corresponds to the above-mentioned reference value of the road map information amount, and the total number of displayed road links can be considered as the visibility evaluation standard. That is, the smaller the display information amount, that is, the total number of displayed road links, the easier the road map is to be viewed. Specifically, the input key 8 is used to set the total number SN of road links displayed on the CRT 18. Further, in order to easily set the visibility evaluation standard, for example, "road density is high", "road density is medium", "road density is low", etc. may be displayed and set interactively. ..

FIG. 8 is a flow chart showing a control program executed by the CPU 1. The extraction operation of the display target road according to the embodiment will be described with reference to this flowchart. C
PU1 starts executing this control program when a main switch (not shown) of the vehicle map display device is turned on. In step S1 after the start of execution, the CD-ROM
The road map data of the display target area set by the input key 8 is read into the D-RAM 22. Note that G
With the current position of the vehicle detected based on the current position information from the PS receiver 12, the traveling direction information of the vehicle from the azimuth sensor 3, and the traveling distance information from the distance sensor 7 as the center, the display target area is automatically displayed. It may be set.

Next, in step S2, the display priority and the visibility evaluation standard set by the input key 8 are input. In this embodiment, an example will be described in which the display priority order is set for the road types shown in FIG. 6 and the visibility evaluation standard of the total number SN of road links is set. In step S3, the display target road search subroutine shown in FIG. 9 is executed, the road map data stored in the D-RAM 22 is searched, and the display target roads of the set display priority and visibility evaluation standard are extracted. .. In step S4, each data of the extracted roads to be displayed is converted from the earth coordinate system to the coordinate system of the display screen, expanded into the V-RAM 20 as bitmap data, and the current position of the vehicle is shown on the road map. Superimpose marks and place names. Further, the bitmap data of the V-RAM 20 is transferred to the CRT 18 via the graphic controller 19, and the road map based on the display priority and the visibility evaluation standard set on the CRT 18 is displayed. Next, in step S5, it is determined whether or not the extraction processing of the roads to be displayed in other areas is continuously performed. If the processing is to be continued, the process returns to step S3, and if not, the execution of the program is terminated.

Next, the procedure for searching the road to be displayed will be described with reference to the subroutine shown in FIG. After calculating the current position of the vehicle in step S11 as described above, step S11
The subroutine shown in FIG. 10 is executed at 12 to create the priority evaluation data table shown in FIG. 11 based on the road network data of the processing target area. The created priority evaluation data table is stored in the D-RAM 22.

FIG. 11 shows a road having a width of 6.0 as a road to be displayed.
An example of a priority evaluation data table when roads of m or more are selected is shown. In this case, the road links of the hierarchization levels 5 to 10 shown in FIG. 6 are set to the display priorities 1 to 6. Note that if only roads with a width of 6.0 m or more are set as display target roads, the display target roads may disappear when the display map is enlarged. Set 1 road link.

Next, in step S13 of FIG. 9, D-
In the priority evaluation data table stored in the RAM 22, road link group data is extracted in order from the highest priority, and in the subsequent step S14, the number PN of road links for each priority L is calculated as shown in FIG. calculate. Then, in step S15, the total GN of the road link number PN for each priority order for which the road link number calculating process is performed.
It is determined whether or not (= PN1 + PN2 + ... + PNL) is less than or equal to the total number SN of road links of the visibility evaluation standard set previously. If GN is less than or equal to SN, the process proceeds to step S16, and if GN exceeds SN. It proceeds to step S18.

In step S16, as shown in FIG. 13, the road link group data of priority L is registered as a display target road link. The registered display target road link is displayed on the CRT 18 in step S4 of FIG. 8 described above. Next, the process proceeds to step S17, and the calculation process of the number of road links and the registration process of the road link to be displayed are completed for the road link group data of all the priorities of the priority evaluation data table stored in the D-RAM 22. If it is completed, the process proceeds to step S18, and if there is unprocessed priority data, the process returns to step S13 to repeat the above process.

In step S18, it is determined whether or not the road links registered as the display target road links are connected. As described above, unless the nodes at both ends of the road link are dead ends, other road links are always connected to both ends of the road link. Now, FIG. 14 (a)
As shown in, when an unconnected road link # 21 in which other road links are not connected to the nodes at both ends is found, all road links in the road map data read into the D-RAM 22 are referred to. Then, as shown in FIG. 14B, the road link # 22 is connected and additionally registered as a display target road link. That is, if the unconnected road link is displayed on the CRT 18 as it is, the road link is not displayed even though there is a road link having a priority level lower than the set priority, so that the road may be erroneously recognized as a dead end. .. Therefore, the connectivity of the road links is confirmed after the search of the display target road, and the display road is repaired so that the road is not interrupted on the way. The newly connected road is displayed on the CRT 18 in a display form different from other roads such as thin lines and broken lines. When the above search processing of the display target road is completed, the process returns to the program shown in FIG.

Next, by the subroutine shown in FIG.
The procedure for creating the priority evaluation data table will be described. In step S21, the search target area of the display target road centering on the current position of the vehicle is determined, and the subsequent step S22
Then, the road map data of the search target area is read from the CD-ROM 16 into the D-RAM 22. In step S23, D
From the road map data stored in the RAM 22, the road link group to be processed is read in units of hierarchized levels of road types, and in the subsequent step S24, the read road link group is set to the hierarchized level first. Are registered in the priority evaluation data table in accordance with the display priority order of. In step S25, it is determined whether or not the above-described priority evaluation data table creation processing has been completed for all road link groups in the road map data stored in the D-RAM 22, and when the processing is completed Returning to the program shown in FIG. 9, if there is an unprocessed road link, step S2
Returning to step 3, the above processing is repeated.

In this way, the road map data is hierarchically stored for each road type and stored in the CD-ROM 16, and the road links to be displayed are extracted from the road map data according to the display priority set by the input key 8. , CRT18
Since it is displayed in, the type of road map required by the occupant can be displayed. Further, since the data search and the data extraction are performed for each stored road link group of each road type, the data search time and the data extraction time are shortened, and the road map display speed is increased. Furthermore, when the set visibility evaluation reference value is exceeded, the extraction of the roads to be displayed is stopped, so that the road map with the optimum density is always displayed and the map is easy to see. Furthermore, when an unconnected road link is detected from the road links extracted as the display target road links, the unconnected road link is connected based on all the stored road map data, and this connected road is linked. Is displayed in a different display form from other roads, so even if there is a road with a low display priority, it is not misidentified as a dead end, and that road is displayed on another road. It can be identified that the road is a connected road having a lower display priority.

In the above-described embodiment, the total number SN of road links is set as the visibility evaluation criterion corresponding to the reference value of the amount of road map information, and the total number SN of road links set by the total number PN of roads to be displayed is set. However, the visibility evaluation standard is not limited to the above-described embodiment, and the total extension distance of the road links may be used as the visibility evaluation standard.

Further, in the above-mentioned embodiment, only the roads searched as the display target roads are displayed, but roads of lower priority other than the display target roads are displayed in a display form different from that of the display target roads, for example, thin lines or broken lines. You may do so. In that case, it is possible to omit the process of detecting unconnected roads and the process of connecting them.

Further, the storage medium of the road map data is not limited to the above-mentioned CD-ROM, and the data structure of the road map data stored in these storage medium is not limited to the above-mentioned embodiment.

In the structure of the above embodiment, the CD-RO
The M16 constitutes a storage means, the input key 8 constitutes a first and second setting means, the CPU 1 constitutes an extraction means, a detection means and a coupling means, and the CRT 18 constitutes a display means.

[0027]

As described above, according to the invention of claim 1, the road map information having a hierarchical data structure for each road type is stored, and the display priority set for each road type is stored. Since the road map information of the corresponding road type is extracted and displayed from the road map information according to the order, the road information required by the occupant can be displayed quickly.
Further, according to the invention of claim 2, the reference value of the road map information amount displayed on the display means is provided, and the extraction is stopped when the road map information amount exceeds the reference value. The map is displayed, making it easier to see. Further, according to the invention of claim 3, when an unconnected road is detected from the extracted road map information, the unconnected road is connected based on the road map information stored in the storage means, and the connection is made. Since the road is displayed in a display mode different from that of other roads, it is possible to prevent the road from being erroneously recognized as a dead end even though there is a road having a low display priority. Further, it is possible to clearly identify that the connected road has a lower display priority than the other roads.

[Brief description of drawings]

FIG. 1 is a diagram for responding to a complaint.

FIG. 2 is a block diagram showing the configuration of an embodiment.

FIG. 3 is a block diagram showing the configuration of an embodiment.

FIG. 4 is a diagram illustrating road links and nodes.

FIG. 5 is a diagram illustrating types of nodes.

FIG. 6 is a diagram showing a structure of road network data in which road links are hierarchized according to road types.

FIG. 7 is a diagram showing a structure of road network data in which road links are hierarchized according to other road types.

FIG. 8 is a flowchart showing an example of a display target road extraction program.

FIG. 9 is a flowchart showing a display target road search subroutine.

FIG. 10 is a flowchart showing a priority evaluation data table creation subroutine.

FIG. 11 is a diagram showing an example of a priority evaluation data table.

FIG. 12 is a diagram showing the number of road links for each display priority order.

FIG. 13 is a diagram showing an example of registration of display target road links.

FIG. 14 is a diagram illustrating a connected state of road links.

[Explanation of symbols]

 1 CPU 2 System Bus 3 Direction Sensor 4 Amplifier 5 A / D Converter 6,9 I / O Controller 7 Distance Sensor 8 Input Key 10 Speaker 11 Sound Generator 12 GPS Receiver 13 Extended I / O 14 Receiver 15 Antenna 16 CD- ROM 17 SCSI controller 18 CRT 19 Graphic controller 20 V-RAM 21 ROM 22 D-RAM 23 Kanji ROM 24 Backup RAM 100 Storage means 101 First setting means 102, 102A Extraction means 103, 103A Display means 104 Second setting means 105 detecting means 106 connecting means

Claims (3)

[Claims] 1. Storage means for storing road map information having a hierarchical data structure for each road type, first setting means for setting a display priority for each road type, and the set display priority. A vehicle map display device comprising: an extracting unit that extracts road map information of a corresponding road type from the road map information according to a rank; and a display unit that displays the extracted road map information. 2. The vehicle map display device according to claim 1, further comprising: second setting means for setting a reference value of the amount of road map information displayed on the display means, wherein the extracting means has road map information. A map display device for a vehicle, wherein extraction is stopped when the amount exceeds the reference value. 3. The vehicle map display device according to claim 1, further comprising: a detection unit that detects a non-connected road from the road map information extracted by the extraction unit, and the detection unit. When an unconnected road is detected, the connecting means connects the unconnected road based on the road map information stored in the storage means, and the display means connects the roads connected by the connecting means. Is displayed in a display form different from that of other roads.