JPH05197334A - Map display method - Google Patents

Abstract

PURPOSE:To always display a road name without increasing map data to be stored in a storage means by determining the display position of the road name in accordance with the position on a picture of an end point of the segment of the road and the condition of the inclination. CONSTITUTION:When one end point P of end points of a segment LP first displayed on the picture is included in the picture, a road name R1234 is displayed in the lower right position of one end point P by the control of a CPU if this segment LP rises toward the right on the picture. When both end points P and Q of the first displayed segment LP are included in the picture, the road name R1234 is displayed in the lower right position or the upper right position of the end point P to the center of the picture by the control of the CPU if the segment LP rises toward the right or falls toward the right on the picture. Consequently, conditions whether one or both end points of the segment first displayed on the picture are included in the picture or not and whether the segment rises toward the right or falls toward the right on the picture determine the display position of the road name.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reads out the start and end point position data and road name data of each line segment of a road to be displayed on the screen of a display means from a storage means, and displays a plurality of roads on the basis of the read data. The present invention relates to a map display method for displaying line segments and road names.

[0002]

2. Description of the Related Art A navigation system has a function of displaying a plurality of line segments and road names on the basis of start and end position data and road name data of each line segment of the road read from the storage means as described above. Such a navigation system is generally constructed as shown in FIG. 7, and the azimuth signal from the azimuth sensor 1 and the mileage signal from the mileage sensor 2 are controlled by interface means (hereinafter referred to as IF) circuits 3 and 4, respectively. Is input to the CPU 5, and based on these signals, the CPU 5 calculates the current position of the vehicle, the vehicle speed, the traveling direction, and the like.

On the other hand, a floppy disk driver (hereinafter referred to as FDD) device 7 is driven under the control of a floppy disk (hereinafter referred to as FD) controller 6, and at this time, when a road is represented by a plurality of line segments in the FD as a storage means. The start and end position data of each line segment, the drawing position data of the road name, and the road name data consisting of the character code necessary for displaying the road name are stored for each road.
5, the start and end point position data and road name data of each line segment of the road to be displayed are read out and stored in the map data buffer memory 8.

Further, these data are stored in a video RAM.
(Hereinafter referred to as VRAM) 9 is appropriately written in the red, green, and blue memory areas, and the write data in each memory area is read by the display controller 10.
Based on the cursor data stored in the cursor display memory area 9, the current position of the vehicle calculated by the CPU 5 is displayed on the map of the display means 11 by the display controller 10 as a cursor.

When any one of the control keys of the FDD device 7 is operated on the operation section 12, an operation signal is input to the key determination section of the CPU 5 via the IF circuit 13, and which key is determined by this key determination section. It is determined whether or not it has been operated, and an instruction is appropriately given from the CPU 5 to the FD controller 6 and the display controller 10 according to the operated key, the FDD device 7 is controlled, and the display screen of the display means 11 is switched. ing.

Further, the clock signal from the timer circuit 14 is input to the CPU 5 via the IF circuit 15.

Then, map matching is performed in order to improve the accuracy of the current position, which is performed by comparing the current position calculated by the CPU 5 with the map data to correct the current position. At that time, the map matching is performed. The memory 16 is used for holding data.

By the way, for example, as shown in FIG.
When the road having the road name of H.234 is represented by a plurality of line segments a, b, ..., The start and end position data of each line segment a, b, ... And the road name data are stored in the FD in the format shown in FIG. That is, the position data (X ₀ ,
Y ₀ ), end point position data (X ₁ , Y ₁ ), line segment b start point position data (X ₂ , Y ₂ ), end point position data (X
₃ , Y ₃ ) and the similar remaining line segment start and end position data are stored in the FD, and the position data (X _n , Y _n ) indicating the position where the road name of this road should be drawn and the road name "R", "1", "2", "3", required for the display of
The character code representing "4" is stored in the FD, and the same applies to other roads.

Then, the map display processing is performed in the procedure shown in the flowchart of FIG. 10, and first, the start and end point position data and road name data of each line segment of the road to be displayed on the display means 11 are read from the FD, The beginning of each line segment read out,
Based on the end point position data, a line segment connecting each start point and end point is displayed on the display screen (step S1), and then it is determined whether or not the road name is displayed on the display screen (step S2).
If the result of this determination is NO, the operation ends.

On the other hand, if the decision result in the step S2 is YES, each character representing the road name is drawn at a predetermined character drawing position based on the read road name data to display the road name (step S3). ..

At this time, when the display area by the display means 11 is set to A, B and C shown in FIG. 8 with respect to the map, the states of the respective display screens are shown in FIGS. 11 (a), 11 (b),
As shown in (c).

[0012]

However, in the conventional case,
Since the position where the character should be drawn as the road name data is predetermined and the position of the road name displayed on the screen of the display means 11 is fixed, as shown in FIG. If only part of the screen is displayed,
As shown in 1 (c), the road name may not be displayed at all, which causes a problem that the driver cannot be provided with sufficient information for navigation.

It is also conceivable that a plurality of character data should be stored in advance in the FD as position data for drawing characters so that the road name is always displayed on the display screen no matter where the display area is set. There is a possibility that map data stored in the FD may be enlarged.

Therefore, the present invention has been made in order to solve the above problems, and the road name can always be displayed on the screen of the display means without causing an increase in the size of the map data stored in the storage means. The purpose is to do so.

[0015]

A map display method according to the present invention stores start and end point position data and road name data for each line when a road is represented by a plurality of line segments in a storage means. Every time, the start and end point position data and road name data of each line segment of the road to be displayed on the screen of the display means are read from the storage means by the control means, and the road is searched based on the read start and end point position data of each line segment. In the map display method of displaying a plurality of line segments that are displayed on the screen and displaying the road name on the screen based on the read road name data, the end points of the line segment of the road that is first displayed on the screen When one of the end points is included in the screen, if the line segment of the road displayed first rises to the right on the screen, it is to the lower right of the one end and falls to the right. For example, at the upper right of the one end point, the road name of the road is displayed by the control means, and when the end points of the line segment of the road displayed first are included in the screen, the first name is displayed. If the line segment of the road is rising to the right on the screen, the control means is located at the lower right of the end point closer to the center of the screen among the end points, and if it is descending to the upper right of the end point closer to the center. Is characterized by displaying the road name of the road.

[0016]

In the present invention, the road name is determined by whether or not one end point or both end points of the line segment first displayed on the screen is included in the screen, and whether the line segment is rising or falling on the screen. Since the position to be displayed is determined, the road name is always displayed on the screen of the display unit without causing an increase in the size of the map data stored in the storage unit.

[0017]

1 is a flow chart for explaining the operation of an embodiment of the map display method of the present invention, and FIGS. 2 to 6 are operation explanatory views.

However, the configuration of the navigation system applied to this embodiment is the same as that of FIG. 7, and the end points of the line segment first displayed on the screen of the display means 11 will also be referred to in the following description with reference to FIG. When one of the end points is included in the screen, if the line segment that is displayed first rises to the right on the screen, it is to the lower right of one end point, and if it falls to the right, it is to the upper right of this one end point. , The road name is displayed under the control of the CPU 5, and when both end points of the line segment displayed first are included in the screen, if the line segment displayed first is rising to the right on the screen, the center of the screen is displayed. At the bottom right of the end point,
In the case of downward sloping, the road name is displayed on the upper right of the end point from the center under the control of the CPU 5, which is different from the conventional method.

By the way, as shown in FIG.
When the road having the road name of 1234 is represented by a plurality of line segments a, b ..., the start and end position data and road name data of each line segment a, b ... Are FD in the data format shown in FIG.
The position data (X ₀ , Y
₀ ), the end point position data (X ₁ , Y ₁ ), the start point position data (X ₂ , Y ₂ ) of the line segment b, the end point position data (X ₃ , Y ₃ ), and the start of each remaining line segment, The end point position data is stored in the FD, and the character codes representing “R”, “1”, “2”, “3”, “4” necessary for displaying the road name of this road are stored in the FD. The same applies to other roads, and as can be seen by comparing FIG. 2 and FIG. 9, the character drawing position data is not included as road name data in the data format of this embodiment.

Next, a map display control procedure is shown in FIG.
Will be described with reference to.

First, the start and end position data and road name data of each line segment of the road to be displayed on the display means 11 are read from the FD, and the display screen is displayed based on the read start and end position data of each line segment. A line segment connecting each start point and end point is displayed (step T1), and the line segment first displayed on the display screen is detected (step T2).

Thereafter, it is judged whether or not one end point of the first display line segment detected in step T2 is within the display screen (step T3), and the judgment result is YE.
If S, it is determined whether or not this first display line segment is rising to the right on the screen (step T4), and if the determination result is YES, the road name is displayed at the lower right of one end point included in the screen. If the determination result of step T4 is NO (step T5), the road name is displayed on the upper right of one end point included in the screen (step T6), and step T6 is displayed.
After the processing of 5 and T6, the operation ends.

At this time, for example, as shown in FIG. 3, when one end point P of the line segment L first displayed on the screen is included in the screen and the line segment L is rising to the right, FIG. By the processing of step T5 of the above, the road name "R123" is displayed at the lower right of the end point P.
4 ”is displayed, and as shown in FIG. 4, when one end point P of the line segment L first displayed on the screen is included in the screen and the line segment L is descending to the right, By the processing of step T6, the road name "R1234" is displayed on the upper right of the end point P.

Returning to FIG. 1, if the decision result in the step T3 is NO, it is decided whether or not both end points of the first display line segment detected in the step T2 are within the display screen ( If the determination result is NO in step T7), the operation is terminated as it is, and if the determination result is YES, it is determined whether or not the first display line segment is rising to the right on the screen (step T8). If the determination result is YES, the road name is displayed at the lower right of the end point near the center of the screen among the end points included in the screen (step T
9) If the decision result in the step T8 is NO, the road name is displayed in the upper right of the end point near the center of the screen among the end points included in the screen (step T10), and steps T9, T1.
After the processing of 0, the operation ends.

At this time, as shown in FIG. 5, both end points P and Q of the line segment L first displayed on the screen are included in the screen,
Moreover, when the line segment L is rising to the right, step T in FIG.
By the processing of 9, the road name "R1234" is displayed at the lower right of the end point P near the center of the screen.

Further, as shown in FIG. 6, when both end points P and Q of the line segment L first displayed on the screen are outside the screen, the determination at step T7 of FIG. 1 is passed with NO. Therefore, the road name is not displayed.

Therefore, the road name is displayed depending on whether or not one end point or both end points of the line segment first displayed on the screen is included in the screen and whether the line segment is rising or falling on the screen. FD because the position to be determined can be determined
The road name can always be displayed on the screen of the display unit 11 without causing an increase in the size of the map data to be stored in, and the driver can be provided with sufficient information for navigation.

In the above embodiment, the case where the invention is applied to the navigation system has been described, but the invention is not particularly limited to the navigation system, and the start and end position data of each line segment of the road to be displayed on the screen of the display means and The present invention can be implemented in the same manner as long as it is a device having a function of reading road name data from the storage means and displaying a plurality of line segments representing roads and road names based on the read data.

[0029]

As described above, according to the map display method of the present invention, whether one end point or both end points of the line segment first displayed on the screen is included in the screen, and whether the line segment is displayed on the screen. Since the position where the road name should be displayed is determined depending on whether the road name is rising or falling to the right, it is possible to display the road name on the screen of the display means without causing enlargement of the map data stored in the storage means. Since it is possible to always provide sufficient information to the user of the displayed map, it is suitable for a navigation system or the like.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining the operation of an embodiment of a map display method of the present invention.

FIG. 2 is an operation explanatory diagram of the present invention.

FIG. 3 is an operation explanatory diagram of the present invention.

FIG. 4 is an operation explanatory diagram of the present invention.

FIG. 5 is an operation explanatory diagram of the present invention.

FIG. 6 is an operation explanatory diagram of the present invention.

FIG. 7 is a block diagram of a general navigation system.

FIG. 8 is an operation explanatory diagram of a conventional map display method.

FIG. 9 is an operation explanatory diagram of a conventional map display method.

FIG. 10 is an operation explanatory diagram of a conventional map display method.

FIG. 11 is an operation explanatory diagram of a conventional map display method.

[Explanation of symbols]

 5 CPU 6 FD controller 7 FDD device 11 display means P, Q end point L line segment

Claims (1)

[Claims] 1. The start and end position data of each line segment when a road is represented by a plurality of line segments and the road name data are stored in the storage means for each road, and the roads to be displayed on the screen of the display means. The start and end position data of each line segment and the road name data are read from the storage means by the control means, and a plurality of line segments representing roads are displayed on the screen based on the read start and end position data of each line segment, In the map display method for displaying the road name on the screen based on the read road name data, when one of the end points of the line segment of the road first displayed on the screen is included in the screen. If the line segment of the road displayed first rises to the right on the screen, it is located at the lower right of the one end point, and if it falls to the right, it is located at the upper right of the one end point. The road name of the road is displayed, and when the end points of the line segment of the road displayed first are included in the screen, the line segment of the road displayed first rises to the right on the screen. In that case, the road name of the road is displayed by the control means at the lower right of the end point near the center of the screen among the both end points, and in the upper right of the end point near the center if the right down direction. How to display the map.