JPH04305116A - Method for drawing guide map of intersection - Google Patents

Abstract

PURPOSE:To prevent a guide map at an intersection from covering an guiding path in advancing direction. CONSTITUTION:The guiding path to a destination is displayed on a map which is displayed on a display screen of a display device 12, at the same time a vehicle position mark is displayed at a fixed position (for example, center) of the display screen, and then the map is displayed in scroll according to driving of the vehicle. During this display, an intersection guide map drawing portion 15h refers to a map data at a next intersection of the guiding path which is stored in the guiding path memory portion 15g and judges a quadrant of a direction where the vehicle advances and then draws the intersection guide map at the quadrant of the display screen which is opposite to this quadrant.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drawing an intersection guide map in a navigation device, and particularly for displaying a guide route to a destination on a map according to the vehicle position.
The present invention relates to a method for drawing an intersection guide map for a navigation device, which draws an intersection guide map superimposed on a map, indicating the direction of travel at the next intersection.

0002

[Prior Art] An automobile navigation device has a large capacity storage device such as a CD-ROM that stores a large amount of map data, a display device, a position measuring device that measures the current location of the automobile, etc. The map data is read from the CD-ROM, a map is drawn on the display screen based on the map data, and the car position mark (location cursor) is placed at a fixed position on the display screen (for example, the center position of the display screen). ), and the map is scrolled according to the movement of the car.

[0003] Maps stored in CD-ROMs are divided into regions with appropriate longitude and latitude widths depending on the scale level, and roads, etc. are divided into regions with vertices (nodes) expressed in latitude and latitude ), and these drawings are performed by sequentially connecting each node with a straight line. Note that a portion that connects two or more nodes is called a road link. Such navigation devices have a route search function that guides the driver by searching for a guidance route that takes the shortest distance or time from the starting point to the destination point. It is designed to be clearly displayed as a road to guide the driver along the guide route to the destination.

[0004] Furthermore, the navigation device has a function of displaying the direction of travel at the next intersection on the guidance route, and an enlarged view of the intersection is superimposed on the map and placed at a certain position (for example, the upper left corner) on the display screen. Along with this, the direction of travel is also displayed using an arrow.

FIG. 6 is an example of a map drawn in a navigation device. The map is drawn so that the direction of travel is directly above (head-up display), and is scrolled according to the progress of the car. There is. CMK is a vehicle position mark, which is fixedly displayed at the center of the display screen. I
RD is the guidance route searched by the route search function,
Other roads RD1, RD2, . . . are displayed in a distinguishable manner. CIM is an intersection guide map that displays the direction of travel at the next intersection C1 on the guidance route, and the road at the intersection is enlarged so that the road on which the car is currently running is facing directly downward (displayed head-up). The map is drawn on top of the map in the upper left corner of the display screen.

[0006]

[Problem to be solved by the invention] Conventionally, intersection guide map C
Since the IM is always drawn at a certain position on the display screen (upper left position of the screen, second quadrant), if the guidance route IRD extends toward the upper left, the guidance route will be drawn in the intersection guide map CI.
There was a problem in that it was hidden by M, which hindered continuous direction changes at short distances.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for drawing an intersection guide map for a navigation device in which the intersection guide map does not hide the guidance route in the direction of travel.

[0008]

[Means for Solving the Problems] The above-mentioned problems are solved in the present invention by means of searching and displaying a guidance route to a destination on a map, and determining the quadrant of the vehicle's direction of travel at the next intersection on the guidance route. This is achieved by means for drawing an intersection guide map in the quadrants of the display screen on the left and right opposite sides of the quadrants.

[0009]

[Operation] Displays the guidance route to the destination on the map displayed on the display screen, and displays the vehicle position mark at a certain position (for example, the center) of the display screen,
The map is scrolled and displayed as the car travels. When the vehicle is traveling and approaches the next intersection on the guidance route, the quadrant in which the vehicle is traveling is determined at the intersection, and an intersection guide map is drawn in the quadrant of the display screen on the left and right opposite to the quadrant. .

0010

Embodiment Overall Configuration FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and 11 is a map data storage unit such as a CD-ROM that stores a road map. Map data consists of (1) a road layer consisting of road link data, intersection data, node data, etc., (2) a background layer for displaying objects on the map, and (
3) It consists of a character layer for displaying municipal names, national highway names, etc.

Reference numeral 12 is a display device (CRT) that draws a map according to the current location of the vehicle, a vehicle position mark, a guidance route searched by the route search function, an intersection guide map, etc.
), 13 is a current location detection unit that calculates the current location based on the travel distance and direction of the vehicle in motion. Current location detection unit 1
Although not shown, 3 is a direction sensor that detects the direction of travel of the vehicle, a geomagnetic sensor (optical gyro, vibration gyro), a vehicle speed sensor that detects the distance traveled, and a current location (longitude, latitude) of the vehicle based on the direction and distance traveled. It has a position calculation CPU that calculates.

Reference numeral 14 denotes an operation unit equipped with a map search key, map scroll key, route search mode key, set key, search start key, etc., and 15 is a map display control device, which displays a map around the current location based on map data. Along with generating an image,
Generate vehicle position marks, guidance route images, and intersection guide maps.

Road Layer The road layer has the data structure shown in FIG. Among these, the road link data RLDT provides attribute information of the corresponding road link, including the total number of nodes on the link, each node composing the link, and the type of road (national highway, expressway, other). It is composed of data such as In addition, the intersection data CRDT is a set of nodes (referred to as intersection constituent nodes) closest to the intersection on links connected to the intersection for each intersection on the map, and the node data NDD
T is a list of all nodes on the map, and for each node it includes location information (longitude, latitude), an intersection identification flag to indicate whether the node is an intersection, and if it is an intersection, intersection data. If the node is not an intersection, it is composed of a pointer that points to the link to which the node belongs. Note that this road information is used in route search processing and the like.

Map display control device In the map display control device 15, 15a reads map data (for example, map data for 4 screens) of a wider range than the screen display range around the current location from the map data storage unit 11 based on the current location data. , a map image drawing unit that generates a dot image map image based on the map data. When displaying a map heads-up, coordinate transformation is applied to the map data so that the azimuth angle θ of the vehicle is rotated around the vehicle position, and a dot image map image is created based on the data obtained by the coordinate transformation. Occur.

15b is a guide route drawing unit that generates a guide route image based on the guide route data from the departure point to the destination obtained by the guide route search process; 15c is a video RAM that stores the map image and the guide route image. It is. The map image drawing unit 15a rewrites the video RAM 15c as the car travels, so that the display range of the display screen does not exceed the image range of the video RAM 15c.
The guide route drawing unit 15b also generates a guide route image according to the travel of the automobile and stores it in the video RAM 15c.

Reference numeral 15d indicates a readout control unit for reading out a map image from the video RAM 15c so that the current location of the vehicle is located at the center of the display screen, and reference numeral 15e indicates a vehicle position mark for displaying the vehicle position mark at the center of the display screen. The generation unit 15f is a guidance route calculation unit, which calculates the shortest route from the departure point to the destination based on the road layer information included in the map data when the departure point and destination are input in route search mode. Calculated as Reference numeral 15g is a guide route storage unit that sequentially stores nodes constituting a guide route from the departure point to the destination.

15h is an intersection guide map drawing unit that generates an intersection guide map image showing the direction of travel at the next intersection on the guidance route; 15i is an intersection guide map storage unit that stores the intersection guide image; and 15j is an intersection guide map memory. A readout control unit 15k is a synthesis unit that reads the dot image from the video RAM 15c, the vehicle position mark image generation unit 15e, and the intersection guide map storage unit 15j, respectively. , the vehicle position mark image, and the intersection guide image are combined and output to the CRT 12 for display.

Intersection Guide Map Drawing Control The intersection guide map drawing control will be explained below according to the flowchart of FIG. As shown in Fig. 4, the map is displayed head-up and scrolled according to the movement of the car, and a car position mark CMK is fixedly displayed at the center of the display screen. It is assumed that the guidance route IRD to the destination is displayed in an identifiable manner superimposed on the image.

The intersection guide map drawing unit 15h determines the next node on the guide route IRD from the guide route storage unit 15g based on the current position of the vehicle, and refers to the road information to determine whether the node is at the intersection. (Step 101). If it is not an intersection, step 101 is repeated to find the first node that is an intersection.

When the intersection node is determined, the distance from the current position of the car to the intersection C1 (see FIG. 4) is calculated, and it is determined whether the distance is less than a certain distance (step 102). Wait until the distance drops below a certain level.

[0021] When the distance to the intersection C1 becomes less than a certain distance, image data for heads-up display of an intersection guide map having an enlarged view of the intersection and an arrow indicating the turning direction is created, and the image data is used to Dot image
The intersection guide map storage unit 15 generates the intersection guide image of
i (step 103).

Next, it is determined whether the direction of the bend is toward the first to fourth quadrants of the display screen (step 104). In addition, as shown in FIG. 5, the first to fourth quadrants of the display screen are horizontal lines HL and vertical lines VL with the car position as the origin.
There are four sections separated by .

The intersection guide map drawing section 15i inputs the quadrant of the turning direction to the readout control section 15j. As a result, the readout control unit 15j displays the intersection guide map CRC in the quadrant of the display screen on the left and right sides opposite to the quadrant in the direction of turning at the intersection C1.
The intersection guide map image is read from the intersection guide map storage unit 15j at the timing of drawing the intersection guide map image. That is, since one screen of images is displayed on the CRT 12 by raster scanning of the beam, when the beam is in a predetermined quadrant position, the intersection guide map image is read out from the intersection guide map storage unit 15i and displayed on the display screen. Draw in a predetermined quadrant. As a result, at the intersection C1, if the turning direction is in the first quadrant direction, the intersection guide map CRC is drawn in the second quadrant, and if the turning direction is in the second quadrant direction, the intersection guide map CRC is drawn in the first quadrant; If the curve is in the direction of the third quadrant, it is drawn in the fourth quadrant, and if the direction of the bend is in the fourth quadrant, it is drawn in the third quadrant (step 105). In the example of FIG. 4, since the turning direction is in the second quadrant, the intersection guide map CRC is drawn in the first quadrant.

Thereafter, the intersection guide map drawing unit 15i monitors whether the car has passed the intersection (step 106), continues displaying the intersection guide map if the car has not passed the intersection, and erases the display of the intersection guide map if the car has passed the intersection. (Step 107), and the above steps are repeated thereafter.

[0025] The above description deals with the case where the map image is displayed head-up on the display screen, but it goes without saying that the present invention can also be applied to the case where the map is displayed with north facing directly above (north-up display). It is.

[0026]Also, although the above example is a case in which the car position mark is drawn at the center of the display screen, the car position mark may be fixedly displayed at a predetermined position below so as to display more of the map in the direction of travel. It can also be applied when

[0027]

[Effects of the Invention] According to the present invention, the quadrant in which the vehicle is traveling at the next intersection on the guidance route is determined;
Since the intersection guide map is drawn in the quadrants of the display screen on the left and right sides opposite to the quadrant, the guidance route in the direction of travel is not hidden by the intersection guide map, making the map easier to see, and moreover, There is no problem in changing the direction continuously.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

[Figure 2] Road information included in map data (road layer)
FIG.

FIG. 3 is a flowchart of intersection guide map drawing control according to the present invention.

FIG. 4 is an example of drawing an intersection guide map according to the present invention.

FIG. 5 is an explanatory diagram of quadrants of a display screen.

FIG. 6 is an example of drawing a conventional intersection guide map.

[Explanation of symbols]

11...Map data storage unit 12...Display device (CRT) 13...Current location detection unit 15...Map display control device 15f... Guidance route calculation unit 15g...guidance route storage section 15h... Intersection guide map drawing section 15i... Intersection guide map storage section 15j...Reading control unit

Claims (1)

[Claims] Claim 1: An intersection that displays a guidance route to a destination on a map according to the vehicle position, fixedly displays a vehicle position mark at a predetermined position on a display screen, and further indicates the direction of travel at the next intersection. In a method for drawing an intersection guide map for a navigation device in which a guide map is drawn superimposed on a map, the quadrant in which the car is traveling at the next intersection is determined, and the intersection guide is displayed in the quadrant of the display screen opposite to the quadrant on the left and right. A method for drawing an intersection guide map, which is characterized by drawing a diagram.