JPH09292829A - Device and method for map display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to always display a map, which is appropriate for the confirmation of traveling position of user's own car, in a screen by changing the scale of a map to be displayed in response to difference of degree of crowding of roads in the area. SOLUTION: When an auto scale mode is selected during the traveling, the number of nodes in the map data for displaying a map in a set scale level are counted, and thereafter, scale level is set. Namely, a judgment whether the number of node N, which is obtained by counting the upper limit average number of node NA stored in a counter 13 and at a scale level set at this stage, exceeds the read-out upper limit number of node NA or not is performed. At this stage, in the case where the number of node N is larger, a judgment whether the level is set at '8' or not is performed. In the case where the level at this stage is not '8', the set scale level is changed to a scale level higher by one stage, and thereafter, a map at the set scale level is displayed in a screen of a monitor 12.

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 having an autoscale function and a map display method.

[0002]

2. Description of the Related Art Conventionally, in a car navigation system, the scale of a map displayed on the screen can be changed stepwise by key operation. Also, apart from this, there is also one having an auto-scale function for automatically changing the scale of the displayed map, that is, enlarging / reducing. Such an auto-scale function is based on the traveling speed, for example, when the traveling speed of the own vehicle is fast, the map is reduced to display a wider road, while when the traveling speed is slow, the map is enlarged to display a detailed map. Some are based on the remaining distance to the destination, such as enlarging the map to show more detailed roads as the destination approaches the destination.

[0003]

However, in the above-described auto-scale function, the map to be displayed is enlarged or reduced regardless of the difference in the surrounding area of the vehicle position, that is, the map is changed to a different scale. For example,
If the speed is high based on the traveling speed, and if the remaining distance is long based on the distance to the destination point, the wide area map is used even though the vehicle is driving in a densely populated city area. Is displayed, it is difficult for the user to confirm the traveling position of the vehicle.

The present invention has been made in view of such conventional problems, and the scale of the displayed map can be automatically changed according to the difference in the surrounding area of the vehicle position. A map display device such as a navigation device and a map display method are provided.

[0005]

In order to solve the above-mentioned problems, in the present invention, a map based on the map information stored in the map information storage means is mainly displayed on the screen and a map displayed on the screen. In the map display device capable of setting the scale, the degree data acquisition means for obtaining the degree data indicating the degree of road congestion in the map displayed on the screen from the map information, and the degree acquired by the degree data acquisition means. Based on the data, the control means for setting the scale of the displayed map is provided.

In such a structure, when the map is displayed on the screen, the scale is set by the control means on the basis of the degree data indicating the density of roads in the map. On the other hand, when different areas are displayed on the screen, the density of roads in the area and the degree data indicating the density change. Therefore, when different areas are displayed, the scale of the displayed map can be changed according to the difference in the density of roads in the areas.

Further, in the map display method of the present invention,
A map display method for automatically switching the scale of a map based on the map information stored in the storage unit and displaying the map on a screen, wherein the degree of road congestion in the acquired map displayed on the screen is displayed. The scale of the map displayed on the screen is switched based on the degree data shown. Also in this method, when different areas are displayed, the scale of the displayed map can be changed according to the difference in the density of roads in the areas.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a navigation device according to the present invention, which is a GPS block for calculating a latitude / longitude of a current position by demodulating / decoding a GPS antenna 1 and a C / A code in the L1 band from a satellite received by the GPS antenna 1. 2 and. The latitude / longitude information calculated by the GPS block 2 is input to the graphic block 3 and taken into the CPU 4. A CD block 5 is connected to the graphic block 3. The CD block 5 reads and outputs map data stored in the map CD-ROM 6, that is, road data, place name data, node data indicating road intersections, road link data, traffic regulation data used for automatic route calculation, etc. To do. C
Various data output from the D block 5 is sent to the CPU via the RAM 7 together with the data read from the ROM 8.
It is sent to the CPU 4 via the peripheral circuit G / A 9. The data read from the CD-ROM 6 is sent to the monitor 12 via the video RAM 11 by the graphic data controller 10, and the monitor 12 is
The map is displayed on the screen.

Further, in the graphic block 3, a counter 13 which is a storage means of the present invention is provided.
The counter 13 is a RAM that can retain stored contents even when the power is off, and has a memory configuration as shown in FIG. That is, in the counter 13,
For each scale level of the map that is determined in stages, the upper limit average node number NA and the lower limit average node number NB, which are the reference data of the present invention, and the number of times KA and KB in which both the node numbers NA and NB are stored, Will be remembered. The scale levels of the map described above include eight levels from level 1 which is a wide area map having a larger scale rate to level 8 which is a detailed map having a smaller scale rate, and the upper limit corresponding to each scale level. The average number of nodes NA and the lower limit average number of nodes NB, and the number of times KA and KB corresponding to them are C
It is data that is updated at any time with the processing of the PU 4 described later. Further, the graphic block 3 includes a D / A
Through the converter 14 and the amplifier 15, a speaker 16 is connected which emits a guide sound composed of a synthetic sound when the route is guided. The graphic block 3 includes setting keys for various operation modes, cursor keys, and a monitor 1.
A key block 17 having a plurality of operation keys (not shown) such as a zoom key, which is an operation means of the present invention, for selectively changing the map to be displayed on 2 into a map of a desired scale is connected.

Next, the operation of the navigation device having the above configuration will be described with reference to the flow charts of FIGS. 3 to 5 showing the processing operation of the CPU 4. That is, CP
When U4 starts its operation when the power is turned on, it detects the vehicle position from the latitude / longitude information received by the GPS block 2 (SA1) and reads the map data corresponding to the vehicle position from the map CD-ROM 6 (SA2). ). The map data to be read at this time is a map of a predetermined scale level indicating the surrounding area of the vehicle position, such as a preset reference scale level or the scale set when the power was turned off last time. This is map data necessary for displaying a level map. Thereafter, the CPU 4 determines whether or not the auto-scale function is working, that is, whether or not the auto-scale mode is selected by the mode setting operation in advance (SA3). If the determination result is NO and the auto-scale function is not working, step S
Based on the map data read in A2, a map showing the surrounding area of the vehicle position is displayed on the screen of the monitor 12 at the predetermined scale level (SA4). Next, it is determined whether or not the scale level of the displayed map is changed by operating the zoom key of the key block 17 (SA
5). If there is no change here, the process returns to step SA1, while if there is a change, the storage process of the number of nodes, which will be described later, is performed (SA6), the map of the changed scale is displayed on the screen (SA7), and then the process proceeds to step SA1. Return.

In the processing of step SA6, as shown in the flowchart of FIG. 4, after counting the number N of nodes in the map data showing the map displayed on the screen in step SA4, that is, the number of road intersections (SB1). ,
It is determined whether or not the change of the scale by operating the zoom key is a change of increasing the scale level, that is, a change of enlarging the map to be displayed (SB2). When the result of this determination is YES, the counter 13 described above
The upper limit average number of nodes NA at the scale level of the map before the change displayed in step SA4 and the corresponding number of times KA are read (SB3). Next, the read upper limit average number of nodes NA, the number of times KA, and step SB
The upper limit average node number NA is recalculated based on the number N of nodes counted at 1, the upper limit average node number NA of the counter 13 is updated to a new one (SB4), and the number of times KA read simultaneously is added once. After updating it, the process returns to the main flow of FIG.

If the determination result in step SB2 is NO and the change of the scale by operating the zoom key is a change of reducing the map to be displayed, the counter 13
After updating the lower limit average number of nodes NB and the number of times KB corresponding to the lower limit average node number stored by performing the same processing as SB3 to SB5 described above, the process returns to the main flow of FIG. As a result, the counter 13 indicates when the user wants to enlarge (or reduce) the displayed map when the number of intersections in the map displayed on the screen is large. Upper limit number of nodes NA and lower limit number of nodes N
B is stored for each scale level and updated at any time.

On the other hand, for example, when the auto scale mode is selected while the vehicle is running and the result of the determination in step SA3 is YES, the map of the display map data, that is, the map of the preset scale level is displayed on the screen of the monitor 12. After counting the number N of nodes in the map data to be displayed, the scale level setting process shown in FIG. 5 is performed (SA9). In such a process, first, the upper limit average node number NA at the scale level set at that time is read out (SC1) while being stored in the counter 13, and the node number N counted in step SA8.
Determines whether or not it is equal to or more than the read upper limit average number of nodes NA (SC2). Here, when the number of nodes N is larger, it is judged whether or not the scale level set at that time is "8", that is, whether or not the scale level is the maximum (SC).
3). Then, if the set level at that time is not "8" (NO in SC3), the set scale level is changed to the scale level one step higher (SC4), and then the scale level shown in FIG.
Returning to the main flow of, the map of the set scale level is displayed on the screen of the monitor 12 (SA1
0), and returns to step SA1.

As a result, for example, when the vehicle approaches a region such as an urban area where roads are dense during traveling, the monitor 1
The map displayed on the second screen will be automatically enlarged. That is, even if the map of the scale level 7 as shown in FIG. 6A should be displayed, the map of the scale level 8 as shown in FIG. 6B, that is,
A map suitable for the user to confirm the traveling position of the vehicle is displayed. However, when the determination result of step SC3 is YES, the set level at that time is "8", and the scale level is such that the display cannot be enlarged further,
As it is, the process returns to the main flow of FIG. 3 to display the initially set scale 8 map.

If the result of the determination at step SC2 is NO, the lower limit average node number NB at the scale level set at that time is read from the counter 13 (SC5) and counted at step SA8. The number of nodes N that has been read is the lower limit average number of nodes NB that has been read
It is determined whether or not the following (SC6). If the number N of nodes counted here is smaller, it is determined whether the scale level set at that time is "1", that is, whether the scale level is the minimum scale level (SC7). If the set level at that time is not "1" (NO in SC7), the set scale level is changed to the scale level one step lower (SC8), and then the process returns to the main flow in FIG. The map of the set scale level is displayed on the screen of the monitor 12 (SA10), and the process returns to step SA1.

As a result, the map displayed on the screen of the monitor 12 is automatically reduced when the vehicle approaches a sparse area such as a suburb while driving. That is, even if the map of the scale level 8 as shown in FIG. 7A is originally displayed, the map shown in FIG.
A scale 7 map is displayed as shown in FIG. However, if the determination result in step SC7 is YES, and the setting level at that time is "1" and the scale level is such that further reduction display is not possible, the process directly returns to the main flow in FIG. 3 and is initially set. Display the scale map that was used. Furthermore, when the determination result of step SC6 described above is NO, that is, from the past use example,
If it is determined that the user does not want to enlarge or reduce the map, the map of the original scale level, which was set before the scale level setting process described above, is displayed on the screen as it is. , And repeats all the processes described above.

As described above, the navigation device automatically changes the scale of the displayed map in accordance with the density of roads in the map displayed on the screen such as around the traveling position of the vehicle, that is, the map. Automatically expands and contracts. Therefore, as described above, for example, when driving in an urban area or the like, a detailed map having a larger scale level is displayed, and when driving in the suburbs, a wide area map having a smaller scale level is displayed. That is, a map is automatically displayed on the screen according to the difference in the area around the vehicle position.

In the navigation device, the number N of nodes in the map data is used as the degree data indicating the density of roads around the traveling position of the vehicle. The density of roads in the displayed map may be known based on other data read from the ROM 6. For example, for each place name data read from the map CD-ROM 6, an absolute degree of road congestion in the area indicated by the place name data is assigned, and the data indicating that is stored in advance, and the place name corresponding to the vehicle position is stored. It is also possible to know the density of roads in the surrounding area based on the vehicle position.

In the navigation device, the average value of the number of nodes N when the user changes the scale level of the map displayed by the user, that is, the upper limit number of nodes NA and the lower limit of nodes NB is stored in the counter 13. Then, based on that, the scale level of the map displayed on the screen was decided. Therefore, it is possible for the individual user to learn how much the density of roads in the map tends to be, so that the map tends to be enlarged or reduced. Then, with the learning function, the map displayed on the screen can be a scale map according to the user's preference. Moreover, since the learning is performed for each of a plurality of scale levels, the user preference can be more faithfully reflected in the scale level of the displayed map.

It should be noted that the learning function described above is eliminated, and the user himself / herself sets the upper limit node number NA and the lower limit node number NB, for example, the scale level of the map displayed on the screen is switched to a map of a desired scale level. The operation may be performed in advance, or the predetermined upper limit node number NA and lower limit node number NB may be stored in the counter 13 or the like.

Further, in the present embodiment, the case where the map showing the surrounding area of the vehicle position is displayed has been exemplified.
Even when the user displays a map showing an arbitrary area,
As described above, the scale level may be changed automatically. Further, in the present embodiment, even when the scale level of the map to be displayed on the screen has to be changed in a plurality of steps, the description is given of the case where the map is displayed for each scale level in the middle of the change. May display only the map of the scale level finally set, without displaying the map of the scale level in the middle.

[0022]

As described above, in the map display device and the map display method of the present invention, when different areas are displayed, the map to be displayed is displayed according to the difference in the density of roads in the areas. Made it possible to change the scale. Therefore, for example, when a map showing the surrounding area of the vehicle position is displayed on the screen, a detailed map with a small scale ratio is displayed when driving in an urban area, and a wide area map with a large scale ratio is running when driving in the suburbs. It can be automatically displayed. As a result, a map suitable for checking the traveling position of the own vehicle can be constantly displayed on the screen.

Further, the control means is provided with a storage means for storing reference data which is read when the scale is set by the control means and serves as a reference for determining the scale to be set, and the control means includes the degree data acquired by the degree data acquisition means and the degree data. If the scale of the map to be displayed is set based on the reference data stored in the storage means, it is set by the control means by changing the reference data set in advance or the reference data set as necessary. The scale of the displayed map can be changed according to the preference of the user. Therefore, the use environment is improved.

Further, the operating means for changing the scale of the map displayed on the screen, and each time the operating means changes the average value of the numerical values indicated by the degree data acquired by the degree data acquiring means before the change. If the storage means stores the average value calculated by the calculation means as the reference data, the user's preference described above can be learned. Therefore, even if the user does not set the reference data himself / herself, it is possible to constantly display the map of a reduced scale according to the user's preference, and the use environment is further improved.

The scale of the map displayed on the screen can be set to a plurality of scales, the calculating means calculates the average value for each scale step, and the storing means stores the reference data for each scale step. In this case, the preference of the user can be reflected more faithfully in the scale of the map to be displayed, so that the use environment can be further improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a navigation device showing one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a memory configuration of a counter.

FIG. 3 is a main flowchart showing a control operation of a CPU in the navigation device.

FIG. 4 is a flowchart showing a node number storage process by the CPU shown in FIG.

5 is a flowchart showing a scale level setting process by the CPU shown in FIG.

FIG. 6 is an example of a map displayed on the screen while driving in an urban area, where (a) is a map of reduced scale level 7 and (b) is
[Fig. 3] is a diagram showing a map of reduced scale level 8, respectively.

FIG. 7 is an example of a map displayed on the screen while traveling in the suburbs, where (a) is a map of scale level 8 and (b) is a map of scale level 7, respectively.

[Explanation of symbols]

 4 CPU 6 Map CD-ROM 12 Monitor 13 Counter 17 Key block

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G08G 1/0969 G06F 15/66 355J

Claims (6)

[Claims] 1. A map display device capable of displaying a map based on the map information stored in a map information storage means on a screen and setting a scale of a map to be displayed on the screen, wherein the map information is displayed on the screen. A degree data acquiring means for acquiring degree data indicating the degree of congestion of roads in the map; and a control means for setting a scale of the map to be displayed based on the degree data acquired by the degree data acquiring means. A map display device. 2. A storage unit for storing reference data which is read when the scale is set by the control unit and serves as a reference for determining the scale to be set, and the control unit is acquired by the degree data acquisition unit. 2. The map display device according to claim 1, wherein the scale of the map to be displayed is set based on the degree data and the reference data stored in the storage means. 3. The map display device according to claim 1, wherein the degree data is data indicating the number of road intersections in the map displayed on the screen. 4. An operation unit for changing the scale of a map displayed on the screen, and each time the operation unit changes the scale of the numerical value indicated by the degree data acquired by the degree data acquisition unit before the change. 3. The navigation device according to claim 2, further comprising a calculation unit that calculates an average value, wherein the storage unit stores the average value calculated by the calculation unit as the reference data. 5. The scale of the map displayed on the screen can be set to a plurality of scales, the calculating means calculates the average value for each scale step, and the storage means calculates the average value for each scale step. The map display device according to claim 4, wherein the reference data is stored in the map display device. 6. A map display method for automatically switching the scale of a map based on the map information stored in a storage unit to display it on a screen, wherein the map is displayed in the acquired map displayed on the screen. A map display method characterized in that the scale of the map displayed on the screen is switched based on the degree data indicating the degree of road congestion.