JPH07318357A - Map display method in navigation apparatus - Google Patents

Abstract

PURPOSE:To provide a map display method, in a navigation apparatus, in which both a present location and a destination can be displayed simply on one screen when it is selected to display a map indicating the relationship between the present location and the destination on a display screen. CONSTITUTION:When it is judged that the execution of a function indicating the relationship between a present location and a destination has been requested, the present location and the destination are acquired (S2). The coordinates of an intermediate point in coordinates are computed by the coordinates of the present location and the coordinates of the destination (S3). A direction to the present location or the destination from the intermediate point is calculated by the intermediate point and the coordinates of the present location or the coordinates of the destination, and how long distance can be displayed in the calculated direction from the center of a screen is computed when maps in individual scales are displayed in the direction (S4). A scale indicating a distance which is large next to the half of the distance between the present location and the destination is adopted as a display scale, and a map is displayed in the display scale which uses the intermdiate point between the present location and the destination as the center.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a map display method in a navigation device mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, in order to support the driving of a vehicle on a geographically unguided land, the current location of the vehicle is detected, and the detected current location is displayed on a CRT together with a road map around it.
Various in-vehicle navigation devices have been proposed which are displayed on a display device including a liquid crystal display element or the like.

In such a navigation device, a destination can be set and input, and the direction of the set and input destination can be displayed on the map screen with an arrow starting from the current position mark. However, it is not enough to know the direction of the destination, and there are cases where it is desired to display the current location and the destination on the same screen. In this type of navigation device, when the user wants to see the current location and the destination on the same screen, the user manually enlarges the map scale to a wide area, checking the scale at which both the current location and the destination can be displayed. I had acquired the relationship between the destination and the current location.

Further, when enlarging the displayed map, in the conventional navigation device, the enlarged map data is first read from the map memory composed of a CD-ROM, an IC card or the like, and the read map data is read. Was displayed on the display screen to perform enlargement processing.

[0005]

In a normal navigation device, the background map screen moves with the movement of the vehicle, centering on the present position mark displayed on the display screen in a superimposed manner on the map. Therefore, a map showing the relationship between the current location and the destination is also displayed centering on the current location mark.

However, as described above, the method of acquiring the relationship between the destination and the current location while manually expanding the display scale of the map and checking the scale at which both the current location and the destination can be displayed is Since the map showing the relationship between the destination and the destination is displayed centering on the current location mark, as the destination moves on the screen as the vehicle travels and gradually approaches the current location, the actual scale It is not possible to obtain detailed map information with the ground. As a result, the map must be manually rescaled to a detailed scale, which is inefficient and cumbersome for the user.

Further, in the conventional navigation apparatus, when enlarging the display map, the map data is always read from the map memory and the information is drawn on the screen, thereby enlarging the map. It took a lot of time to read the data and display the enlarged map for the drawing process. Therefore, it takes time for the user to confirm the enlarged map, and the next navigation operation cannot be performed quickly.

The present invention has been made in view of the above technical problems, and when it is selected to display a map showing the relationship between the present location and the destination on the display screen, the present location and the destination can be easily displayed. An object of the present invention is to provide a map display method in a navigation device in which both points are displayed on one screen and the number of operations such as scale change operation can be reduced. It is another object of the present invention to provide a map display method in a navigation device that allows a user to quickly check an enlarged map and perform a quick navigation operation when the map is enlarged.

[0009]

According to a first aspect of the present invention, there is provided a map display method in a navigation device for achieving the above object, wherein a map showing a relationship between a present location and a destination set and input is displayed on a display screen. In the case of displaying in, the intermediate point between the current location and the destination is obtained, and both the current location and the destination are displayed at the most detailed map scale that fits on the display screen centering on the obtained intermediate point. .

According to this map display method, when a map showing the relationship between the present location and the destination that has been set and input is displayed on the display screen, the present location and the destination are centered around the midpoint between the present location and the destination. Since both points are displayed at the most detailed map scale that fits on the display screen, the user can simply select to display a map showing the relationship between the current location and the destination on the display screen, and automatically It is possible to display the map to the destination on one screen and check the relationship between the current location and the destination, leading to a reduction in the number of operations such as changing the scale.

A map display method in a navigation device according to a second aspect is characterized in that the process according to the first aspect is performed at regular time intervals while the vehicle is traveling. According to this map display method, even while the vehicle is traveling, as a result of the series of processing being performed at predetermined time intervals, the scale and the intermediate point of the displayed map are constantly updated, and the current location and the destination are displayed on one screen. Can be displayed farthest apart. Therefore, the user knows the outline of the map when the distance between the current location and the destination is long, and the detailed information between the current location and the destination when the distance between the current location and the destination is short. Map information can be automatically acquired.

According to a third aspect of the present invention, there is provided a map display method in which a first image memory for displaying on a screen and a second image memory for transferring image data to the first image memory are provided. When the map is enlarged using the map image, the map image drawn in the first image memory before the display scale change is used for simple enlargement, and then or simultaneously, the map data after the scale change is displayed. It is characterized in that the map image is read out from the map memory and written into the second image memory, the written map image is transferred to the first image memory, and the simple enlarged map is displayed again on the formal map.

According to this map display method, when a map enlargement operation is performed, first, the map image drawn in the first image memory before the display scale change is used to perform simple enlargement, so Can quickly check the outline of the enlarged map. Also, after the simple enlargement or at the same time as the simple enlargement,
Since the map data after the scale reduction is read from the map memory and written in the second image memory, the written map image is transferred to the first image memory and displayed again on the formal map from the simple enlarged map. Navigation operations can be performed quickly.

[0014]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 2 is a block diagram showing the configuration of the navigation device according to the first embodiment to which the map display method of the present invention is applied. The navigation device according to the present embodiment is mounted on a vehicle and used, and includes a navigation device body 1 that controls a control center. The navigation device body 1 includes a CPU 11, a ROM 12, and a RAM 13.
And the VRAM 14 and the like, the present position of the vehicle is detected, and the detected present position is displayed together with a map around the present position. The VRAM 14 is for temporarily holding road map data.

The navigation device body 1 is provided with respective outputs of a wheel speed sensor 2 for detecting the traveling distance of the vehicle, a gyro 3 for detecting the traveling direction of the vehicle, and a geomagnetic sensor 4 for detecting the earth's magnetic field. In the navigation device main body 1, the current position of the vehicle is detected based on each of the given outputs, and the road map data including the detected current position of the vehicle is read from the road map memory 5 configured by the CD-ROM. Stored in the VRAM 14. The present location data and road map data are given to a display device 6 including a CRT, a liquid crystal display element, a plasma display element, etc., and the present location of the vehicle is displayed on the display device 6 in an overlapping manner on a road map in the vicinity thereof. .

The wheel speed sensor 2 may be replaced by, for example, a vehicle speed sensor, and various kinds of gyros such as a vibration gyro, a gas rate gyro, and an optical fiber gyro can be applied. In addition to the CD-ROM, for example, an IC card can be applied to the road map memory 5. The detection of the current position in the navigation device body 1 is basically performed by so-called self-contained navigation based on the outputs of the wheel speed sensor 2 and the gyro 3. Specifically, the navigation device body 1 integrates the output of the wheel speed sensor 2 over a predetermined time, and also integrates the output of the gyro 3 during the predetermined time.
The traveling distance of the vehicle in the predetermined time is obtained from the integrated value of the wheel speed sensor 2, and the traveling direction is obtained from the integrated value of the gyro 3. Therefore, for example, if the correct position of the vehicle is input before starting the vehicle, the transition of the position of the vehicle thereafter can be detected.

Incidentally, in order to detect the present position in the navigation device body 1, a so-called map matching method (for example, Japanese Patent Laid-Open Nos. 63-148115 and 64-53112) is used.
(See Japanese Patent Publication) may be used in combination. That is, using the fact that the position of the vehicle is limited on the road in principle, the current position is corrected to the position on the road in the vicinity thereof, and the current position is corrected on the road. As a result, it is possible to prevent the error of the current position detected based on the outputs of the wheel speed sensor 2 and the gyro 3 from being accumulated, and to improve the accuracy of position detection.

A beacon receiver 7 is connected to the navigation device body 1. The beacon receiver 7 is for receiving data such as position information and traffic information (intersection name, destination information, traffic jam information, accident information, etc.) radiated from a beacon antenna installed on the roadside of the road, etc. is there. The road information received by the beacon receiver 7 is given to the navigation device body 1.

Further, the navigation device body 1 has a G
A PS (Global Positioning System) receiver 8 is connected. The GPS receiver 8 receives radio waves transmitted from GPS satellites that are orbiting the earth. In the navigation device body 1, the current position of the vehicle is directly detected based on the propagation delay time of the received radio waves.

In the navigation device body 1, the current position obtained by the self-contained navigation, the current position obtained based on the position information received by the beacon receiver 7, or the radio wave received by the GPS receiver 8 is obtained. One of the present locations is selectively adopted according to a predetermined standard. The display device 6 has, for example, a display screen of 240 dots vertically by 320 dots horizontally, and a power switch for activating the navigation device and a road map displayed on the display screen of the display device 6 are provided around the display screen. A keyboard 9 provided with a scroll button for scrolling, a scale change button for changing the scale of the map, and other various input keys for the user to operate to execute various functions in this navigation device. It is provided. The operation output of the keyboard 9 is given to the navigation device body 1.

FIG. 1 is a flow chart showing a control procedure when a map showing the relationship between the present location and the destination is displayed on the display screen. In the following description, it is assumed that the setting input of the destination has been completed by operating the keyboard 9. In the initial state, the keyboard 9
By the operation, it is determined whether or not there is a request to execute the function of displaying the relationship between the current position and the destination with respect to the navigation device body 1 (step S1). If it is determined that the navigation device body 1 has been requested to execute the function of displaying the relationship between the current location and the destination, the current location and the destination are acquired (step S2). Then, the coordinates of the intermediate point between these coordinates are calculated from the current position coordinates and the destination coordinates (step S3). Specifically, the center position (1/2) of the straight line connecting the current position coordinates and the destination coordinates is obtained.

When the calculation of the intermediate point between the current location and the destination is completed, the direction from the intermediate point to the current location or the destination is further calculated from the intermediate point and the current location coordinates or the destination coordinates, and each direction is calculated with respect to this direction. For each reduced scale map display, calculate how much distance can be displayed from the center of the screen in the calculated direction (step S
4).

Specifically, referring to FIG. 3, first, the direction from the intermediate point to the current position or the destination is obtained by coordinate calculation, and the angle with respect to the obtained direction is θ. Further, the number of dots to the screen edge in the vertical and horizontal directions corresponding to the display screen is obtained. Screen size is vertical 240 × horizontal 3
In the case of 20 dots, the angle θ1 with respect to the diagonal direction of the screen is calculated by the following equation (1).

[0024]

[Equation 1]

Therefore, when θ ≦ θ1, the number of dots X1 from the center of the screen to the screen edge in the vertical direction is calculated by the following equation (2).

[0026]

[Equation 2]

On the other hand, when θ ≧ θ1, the number of dots X2 from the center of the screen to the end of the screen in the horizontal direction is calculated by the following equation (3).

[0028]

[Equation 3]

The number X1 or X2 of dots from the screen center to the screen edge in the direction of the angle θ obtained by the above method is defined as X. However, since this X is the number of dots, it is converted into a distance on the display screen by the pitch between dots. The converted distance is R (cm). And this R
And the distance A (km) from the intermediate point, which is a physical distance, to the current position or the destination, and by calculating the ratio of R and A, the current position and It is calculated whether the destination can be displayed at both ends of the screen. For example, if R = 5 cm and A = 25 km,
The display scale at which the current location and the destination can be displayed at both ends of the screen is 1 / 50,000.

Referring again to FIG. 1, when the calculation of the display scale is completed, based on the calculated result, the scale indicating the distance next larger than half the distance between the present location and the destination is set as the display scale. Adopted, as shown in FIG. 4, a map is displayed at a display scale centered on an intermediate point between the present location and the destination (step S5). In FIG. 4, M1 is a present position mark and M2 is a destination mark.

Then, it is judged whether or not there is a request for ending the execution of the function for displaying the relationship between the current position and the destination with respect to the navigation device body 1 (step S1). If there is no execution end request for the function for displaying the relationship between the current location and the destination, the process returns to step S2. If there is an execution end request for the function for displaying the relationship between the current location and the destination, the operation returns to the initial state.

As described above, when a map showing the relationship between the present location and the destination is displayed on the display screen, an intermediate point between the current location and the destination is obtained, and the present location and the destination are centered around the obtained intermediate point. Since both points are displayed at the most detailed map scale that fits on the display screen, the user can simply select to display a map showing the relationship between the current location and the destination on the display screen, and automatically It is possible to display the map to the ground on one screen and check the relationship between the current location and the destination, which leads to a reduction in the number of operations such as changing the scale.

Further, as a result of the series of processing being performed at predetermined time intervals even while the vehicle is traveling, the scale and the intermediate point of the displayed map are constantly updated, and the present location and the destination are separated most on one screen. Can be displayed. Therefore, the user knows the outline of the map when the distance between the current location and the destination is long, and the detailed information between the current location and the destination when the distance between the current location and the destination is short. Map information can be automatically acquired.

FIG. 5 is a block diagram showing the configuration of a navigation apparatus according to the second embodiment to which the map display method of the present invention is applied. In the figure, the same functional parts as those in FIG. 2 are designated by the same reference numerals. The navigation device of the present embodiment is almost the same as the navigation device described in the first embodiment, but its characteristic is that the first VRAM 15 for displaying on the screen and the image data in the first VRAM 15 are displayed. The second VRAM 16 for transfer is used to enlarge the displayed map.

FIG. 6 is a flow chart showing a control procedure for enlarging the display map. In the initial state, it is monitored whether or not the scale change button has been operated (step S1). When it is determined that the enlargement button has been pressed to enlarge the displayed map (step S2), the enlarged map area is the bit of which area of the map image currently drawn in the first VRAM 15. It is determined whether or not the map is pointed, and as shown in FIG. 7, the area is displayed by enclosing it with a square frame (step S3). As a method of designating this enlargement area, for example, each time the enlargement button is pressed with the center of the screen as the center, the rectangular frame indicating the enlargement area is gradually narrowed at a constant rate, or two points are designated centering on the center of the screen. For example, a method of designating a rectangular frame indicating the enlarged area can be considered.

When the area to be enlarged in the map is obtained, the bitmap image data corresponding to the inside of the rectangular frame is acquired from the map image drawn in the first VRAM 15 before the display scale change ( Step S4). Then, as shown in FIG. 8, the image data acquired in the screen size is simply enlarged and displayed (step S5). Here, the simple enlargement means a well-known process of decompressing the bitmap data drawn in the first VRAM 15, and when the simple enlargement process is performed, the enlarged and displayed map is considerably jaggy (screen When you zoom in, you may see jagged edges that appear noticeably on diagonal lines, etc.
The display contents are coarse (in reality, the place name and route name are enlarged and displayed in large size). However, since this simple enlargement can be executed only by calculation based on the data from the first VRAM 15, there is an advantage that it can be enlarged at a considerably high speed.

Next, in order to draw the officially enlarged map, the map data after the scale change is read from the map memory 5 and the map is drawn in the second VRAM 16 (step S6). The timing of drawing the map on the second VRAM 16 may be performed after the simple enlargement or at the same time as the simple enlargement. During this drawing, the user wants to know, for example, traffic information, facility information, and the like, and in order to switch the menu screen, whether or not another navigation operation has occurred is monitored at regular time intervals (step S7). Here, if another navigation operation occurs, the drawing process is interrupted and the process corresponding to the navigation operation is executed. On the other hand, the other navigation operation does not occur, and the second
When the drawing process on the VRAM 16 is finished (step S8), the contents drawn on the second VRAM 16 are transferred to the first VRAM 15, and the simple enlarged map is displayed on the formal map as shown in FIG. Perform again (step S9). At this time, the place name and the route name are displayed in an appropriate size, and the narrow streets also appear accurately. For this display, the drawing contents may be transferred all at once, or, for example, the interlace method used in the NTSC system may be adopted to transfer the drawing contents from the partial portion so that all transfers are completed within a certain time. Good. For example, when the drawing content is transferred from the partial portion by adopting the interlace method or the like, the display screen changes step by step, so that the user does not feel uncomfortable when viewing the screen.

In this way, when the first VRAM 15 for displaying on the screen and the second VRAM 16 for transferring the image data to the first VRAM 15 are used and the map enlargement operation is performed. First, before changing the display scale
Since the simple enlargement is performed using the map image drawn in the VRAM 15 of, the user can quickly check the outline of the enlarged map.

After the simple enlargement or at the same time as the simple enlargement, the map data after the scale change is read from the map memory 5 and written in the second VRAM 16, and the written map image is transferred to the first VRAM 15. Since the simple enlarged map is displayed again on the official map, the next navigation operation can be performed quickly. It should be noted that the present invention is not limited to the above embodiment, and many modifications and changes can be made within the scope of the present invention.

[0040]

As is apparent from the above description, claim 1
According to the map display method described, when displaying a map showing the relationship between the current location and the destination on the display screen, the midpoint between the current location and the destination is obtained, and the current location and the destination are centered around the obtained midpoint. Since both points of the ground are displayed at the most detailed map scale that fits on the display screen, the user can simply select to display a map showing the relationship between the current location and the destination on the display screen and automatically It is possible to display the map to the destination on one screen and check the relationship between the current location and the destination, leading to a reduction in the number of operations such as changing the scale.

According to the map display method of the second aspect, as a result of the series of processing being performed every predetermined time even while the vehicle is traveling, the scale and the intermediate point of the displayed map are constantly updated, and the map is displayed on one screen. Since the current location and the destination can be displayed at the maximum distance with, the user knows the outline of the map when the distance between the current location and the destination is large,
On the other hand, when the distance between the current location and the destination is short, detailed map information between the current location and the destination can be automatically acquired.

According to the map display method of the third aspect, when the map is magnified, the map image drawn in the first image memory before the display scale change is first used to simply magnify the map. Therefore, the user can quickly check the outline of the enlarged map. Further, after the simple enlargement or at the same time as the simple enlargement, the map data after the scale change is read from the map memory and written in the second image memory, and the written map image is transferred to the first image memory and simply enlarged. Since the map is displayed again on the official map, the next navigation operation can be performed quickly.

[Brief description of drawings]

FIG. 1 is a flowchart showing a control procedure when a map showing a relationship between a current location and a destination is displayed on a display screen.

FIG. 2 is a block diagram showing a configuration of a navigation device according to a first embodiment to which the map display method of the present invention is applied.

FIG. 3 is a diagram for explaining a method of calculating a display scale.

FIG. 4 is a diagram showing an example of a map display screen when a current location and a destination are displayed on the same screen.

FIG. 5 is a block diagram showing a configuration of a navigation device according to a second embodiment to which the map display method of the present invention is applied.

FIG. 6 is a flowchart showing a control procedure relating to enlargement processing of a display map.

FIG. 7 is a diagram showing a map display screen after inputting an enlarge button.

FIG. 8 is a diagram showing a map display screen after execution of simple enlargement.

FIG. 9 is a diagram showing a map display screen after drawing a formal map.

[Explanation of symbols]

 1 Navigation Device Main Body 11 CPU 12 ROM 13 RAM 14 VRAM 15 First VRAM 16 Second VRAM 2 Wheel Speed Sensor 3 Gyro 4 Geomagnetic Senna 5 Road Map Memory 6 Display Device 7 Beacon Receiver 8 GPS Receiver 9 Keyboard

Claims (3)

[Claims] 1. A navigation device mounted on a vehicle, used to detect the current location of the vehicle and display the detected current location together with a map of the surrounding area,
This is a method for displaying a map on the display screen, and when a map showing the relationship between the current location and the destination that has been set and input is displayed on the display screen, an intermediate point between the current location and the destination is obtained, and A map display method for a navigation device, characterized in that both the current location and the destination are displayed at the most detailed map scale centered on the obtained intermediate point on the display screen. 2. A map display method for a navigation device, wherein the process according to claim 1 is performed at regular time intervals while the vehicle is traveling. 3. A navigation device mounted on a vehicle, used to detect the current location of the vehicle and display the detected current location together with a map of the surrounding area.
A method for displaying a map on a display screen, which uses a first image memory for displaying on the screen and a second image memory for transferring image data to the first image memory However, if a map enlargement operation is performed, the first
Simple enlargement is performed using the map image drawn in the image memory of, and after or at the same time, the map data after the scale change is read from the map memory and written in the second image memory, and the written map image is A map display method for a navigation device, characterized in that the map is transferred to a first image memory and displayed again from a simple enlarged map to an official map.