JP3301420B2 - Map display device - Google Patents

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 for displaying a map three-dimensionally on a screen.

[0002]

For example, in a map display device used in a car navigation system, a map is displayed three-dimensionally on a screen so that a user can intuitively understand the map. Has been done. In some cases, when performing a three-dimensional map display, the viewpoint altitude can be changed in order to improve the visibility of the map display.
As one example, as shown in FIG. 9A, the user sets the viewpoint height of the bird's-eye view to several predetermined levels (for example, low,
There is a car navigation device configured to be able to select and set from among three levels (medium and high).

In general, in a three-dimensional map display in which buildings and the like are three-dimensionally displayed on a screen, if a set viewpoint altitude is low, a road or a building that a user wants to see is a high building or the like located on the near side. If they are hidden behind and are not displayed, or if the set viewpoint altitude is high, the three-dimensional effect and perspective that can be obtained due to the degree of overlap between buildings and the like may be impaired. These circumstances vary in various ways depending on the buildings and roads displayed on the screen, their arrangement, terrain, map portions that the user wants to see, and the like. However, in the above-described car navigation device, since the user can select only three viewpoint heights, there is a case where an optimum viewpoint cannot be set according to such various circumstances. Further, when the viewpoint height is switched, the screen display changes greatly at a time, so that it is difficult for the user to grasp the correspondence between the screen display before the switch and the screen display after the switch.

On the other hand, as shown in FIG. 9 (b), there is a car navigation apparatus in which the viewpoint altitude can be increased or decreased in a number of steps at a constant altitude. According to this car navigation device, the user can set the viewpoint to a desired altitude according to the circumstances and purpose on the map display described above. However, when changing the viewpoint from a low altitude to a high altitude, there is an operational inconvenience that the target viewpoint altitude cannot be easily set even if the user operates a switch or the like to sequentially increase the viewpoint altitude by a fixed altitude. Was. Further, in the relatively high viewpoint altitude, since the change of the map being displayed on the screen by sequentially increasing or lowering the viewpoint altitude altitude by a constant is small, the user increases the viewpoint also operates the switch It was hard to get a feeling of feeling and a feeling of descent.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to set a desired viewpoint height with good operability when a three-dimensional map is displayed, and to display a screen with a viewpoint height changing operation. Is to provide a map display device that changes smoothly.

[0006]

Means for Solving the Problems To achieve the above object, the means described in claim 1 can be adopted. According to this means, the screen control management means has a high viewpoint altitude (low
As the map is displayed in a wide area (details),
When the depression angle is set so that the rate of change becomes large (small)
Both display positions of the cursor showing the current position of the vehicle on the map
To the display position that has been gradually moved to the upper (lower) side of the screen.
Cursor viewed from the viewpoint position at the set viewpoint altitude
Displayed together with the 3D map display, the current vehicle position and viewpoint position
If the location is almost the same as the location,
Display as an inverted view and hide the cursor.
Therefore, even if the depression angle changes according to the viewpoint altitude,
The current position on the diagram can be displayed appropriately,
Also, whether the viewpoint altitude is high or low
The area near the current position of the vehicle and the distance from the current position
Area is displayed on the screen in a well-balanced manner.
This gives the user an overall grasp from a perspective
Display can be performed easily, and
Map display changes smoothly as altitude changes
You can feel it.

[0007]

[0008] According to the means described in claim 2, three-dimensional
Point the cursor on the map from the viewpoint
The line-of-sight distance L to the current position, which is
When the degree is H, a value satisfying L = H · cosec θ can be obtained.

[0009]

According to the third aspect of the present invention, the screen control management means can set the line of sight upward or downward independently of the setting of the viewpoint altitude. It is possible to display a three-dimensional map at a position immediately below the viewpoint, and also to display a building, an elevated road, or the like in a state where the user looks up from the viewpoint. Thereby, the user can obtain more information from the three-dimensional map display.

[0011]

[0012]

Therefore, by automatically setting the depression angle in the line-of-sight direction according to the setting of the viewpoint altitude as described above, the area immediately below the viewpoint position can be obtained regardless of whether the viewpoint altitude is high or low. The region far from the viewpoint is displayed in a well-balanced manner on the screen, and the display can be performed so that the user can easily grasp the entire region extending from near to far from the viewpoint.

[0014]

According to the fourth aspect of the present invention, the screen control management means calculates the depression angle θ indicating the line of sight as: θ = N × (maximum depression angle−minimum depression angle) + minimum depression angle N = log2 (viewpoint height / minimum Since the setting is based on the viewpoint height / log2 (maximum viewpoint height / minimum viewpoint height), an appropriate setting is performed by using a logarithmic function so that the width of change in the line-of-sight direction varies according to the change in the viewpoint height. be able to.

According to the means described in claim 5 , the specific point on the map ahead of the line of sight is set to the current position on the map or ahead of the current position. As described above, even when the map display on the screen is constantly changing, the screen is drawn with a line of sight looking down on the current position of the vehicle, so that the occupant of the vehicle can recognize the current position of the vehicle in the map displayed on the screen. The position can be easily grasped.

[0017]

According to the means described in claim 6 , the screen control management means sets the coordinates indicating the display center of the screen to (X, Y).
The change rate N is set as N = log2 (viewpoint height / minimum viewpoint height) / log2 (maximum viewpoint height / minimum viewpoint height), and the display position of the cursor is set by (X, NY). Similarly to the above, based on the change rate set according to the change in the viewpoint altitude, the display position of the cursor in the screen can be set to be appropriate .

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the map display device of the present invention is applied to a car navigation device will be described below with reference to FIGS. FIG. 1 shows a schematic functional block diagram of the entire configuration of the car navigation device 1.
In FIG. 1, a position detection unit 2 is a GPS (Global P
ositioning System) It is a part that consists of a receiver, a gyro sensor, a vehicle speed sensor, etc., and calculates the current vehicle position. Since each of the sensors has an error having a different property, the position detecting unit 2 is configured to be usable while interpolating. In this case, if the current position can be calculated, it is not necessary to provide all of these sensors, and it is sufficient to provide at least one of the sensors.

The map data storage 3 is a device for inputting various data including so-called map matching data, map data, and target data for improving the accuracy of position detection, and includes a DVD player, a hard disk device,
It is composed of a CD player and the like.

The switch information input unit 4 (corresponding to an input means in the present invention) is a switch mounted on the left, right, up, or down of a display device to be described later. It comprises a switch, a line-of-sight change switch for changing the line-of-sight direction upward and downward, and the like. When the viewpoint altitude change switch and the line of sight change switch are operated sporadically,
A viewpoint altitude change command and a line of sight change command for changing the viewpoint altitude and the line of sight only by one step are output, and when the operation state continues, the viewpoint altitude change command and the line of sight change command are continuously provided at predetermined time intervals during the operation state. Output.

The memory unit 5 is composed of, for example, a ROM or a RAM, and the ROM includes the car navigation device 1.
And a RAM for storing an execution program for operating the
, Temporary data when the program is executed, map data acquired from the map data storage unit, and the like are temporarily stored.

The display unit 6 displays a map, a destination selection screen, and the like, and is composed of, for example, a liquid crystal display device. The screen includes a current position mark of the vehicle input from the position detection unit 2, map data input from the map data storage unit 3, and a route guide line or a mark of a target setting point in a state of being superimposed on the map. And other additional data. The voice output unit 7 outputs voice for guidance and explanation of screen operation.

The control unit 8 is mainly composed of a microcomputer, and automatically selects an optimal route from the current position to the destination in accordance with an operation on the switch information input unit 4 to provide a route guide line. It performs a route guidance function to be displayed, performs map matching processing, synthesizes guidance voices, and draws a map according to the set viewpoint altitude and viewing direction.

The control unit 8 includes a map data acquisition unit 9, a map matching unit 10, a route calculation unit 11, and a route guidance unit 1.
2, a drawing unit 13, a screen control management unit 14, and the like.

The map matching section 10 includes a position detecting section 2
The current position of the vehicle is specified on which road, using the position information of the vehicle detected in the above and the road shape data of the map data acquired from the map data storage unit 3. At this time, the map data acquisition unit 9 acquires necessary map data from the map data storage unit 3. Further, the user operates the switch information input unit 4 to display a desired map or the like, and sets a destination. The route calculation unit 11 calculates the information on the current position calculated by the map matching unit 10 and the optimum route to the departure point and the destination specified by the user.

The route guidance unit 12 calculates the result of the route calculation and the road shape data stored in the map data,
A point required for route guidance is calculated from the position information of the intersection, the position information of the railroad crossing, and the like, and what kind of route guidance (turn right or turn left) is calculated.

The drawing unit 13 draws a map of the current position, a schematic diagram of a highway, an enlarged view near an intersection near an intersection, etc. in accordance with an instruction from the screen control management unit 14, and draws the display unit 6.
To display. The screen control management section 14 (corresponding to a screen control management means in the present invention) sets a viewpoint height based on a viewpoint height change command input from a viewpoint height change switch. Also, the screen control management unit 14
Sets the gaze direction independently of the viewpoint altitude based on a gaze change command input from the gaze change switch.

The map data acquisition unit 9 acquires map data required by each of the processing units from the map data storage unit 3,
Provided to each processing unit. Each of the above-described processes is executed using the ROM and the RAM of the memory unit 5.

The map drawn by the drawing unit 13 is a three-dimensional map (for example, a bird's-eye view or a three-dimensional map), and includes building shape data, building height information, road shape data, and the like stored in the map data. Buildings, three-dimensional intersections, and the like are three-dimensionally drawn based on the set viewpoint altitude and line-of-sight direction.
Further, based on the information calculated by the route guidance unit 12, when the vehicle travels and reaches a position to be route-guided, a desired image is drawn on the drawing unit 13 or a predetermined sound is output to the sound output unit 7. Guide the user to the destination.

Next, the operation of the above configuration will be described with reference to FIGS. By operating the viewpoint height change switch, the user can change the viewpoint height when the map is three-dimensionally displayed on the display unit 6. FIG. 2 shows a flowchart of a viewpoint height setting process performed by the screen control management unit 14. In FIG. 2, the screen control management unit 14 first determines whether or not the viewpoint height change switch has been operated (step S1), and if not (NO), ends the viewpoint height setting process.
On the other hand, the screen control management unit 14 operates when the viewpoint height change switch is operated and a viewpoint height change command is given (YE
In S), the viewpoint height is set as follows.

That is, based on the viewpoint height set before the change (before operating the viewpoint height change switch), the screen control management unit 14 changes the viewpoint height which is increased or decreased by a single operation of the viewpoint height change switch. Amount (altitude change amount)
Is calculated as in the following equation (1) (step S
2). Altitude change amount = viewpoint altitude before change × change ratio + minimum change altitude (1) In this equation (1), (viewpoint altitude before change × change ratio)
Corresponds to the ratio change height in the present invention, and the minimum change height corresponds to the constant value change height in the present invention. Then, the screen control management unit 14 determines whether the viewpoint altitude change switch has been operated to the “altitude ascending side” or the “altitude ascending side” (step S3). If it is (YES), the viewpoint height is set according to the formula (2) (step S4), and if it is operated on the "altitude lowering side" (NO), the viewpoint height is set according to the formula (3) (step S5). Viewpoint altitude = viewpoint altitude before change + altitude change amount (2) Viewpoint altitude = viewpoint altitude before change−altitude change amount (3) The surface control management unit 14 applies the above formulas (1) to (1) to the drawing unit 13. The viewpoint height obtained by the expression 3) is output, and the display unit 6 is instructed to draw a three-dimensional map viewed from the viewpoint height (step S6), and the viewpoint height setting process ends.

FIG. 3 shows the relationship between the number of operations and the set viewpoint altitude and the relationship between the number of operations and the altitude change amount when the viewpoint altitude change switch is operated on the “elevation ascending side”. Shown by dashed lines. here,
The change ratio is set at 1/16, the minimum change altitude is set at 0.5 m, and the initial viewpoint altitude is set at 0 m.

As shown in FIG. 3, the viewpoint altitude with respect to the number of operations of the viewpoint altitude change switch increases exponentially as a whole, and the initial viewpoint altitude, which was 0 m, becomes almost 600 m by 71 altitude ascent operations. It becomes the viewpoint altitude. Then, as the viewpoint altitude is higher, the ratio change altitude (viewpoint altitude before change × change ratio) in equation (1) becomes larger, and the altitude change amount by operating the viewpoint altitude change switch becomes larger. When the viewpoint altitude is low, the ratio change altitude is small, but the minimum change altitude (constant value change altitude) is added in equation (1). Altitude rises. If you continue to operate the viewpoint altitude change switch,
During the continuation of the operation, the viewpoint height increases by one step at predetermined time intervals according to the curve shown in FIG.

As described above, according to the present embodiment,
Each time the viewpoint height change switch is operated, the screen control management unit 14 adds the ratio change height obtained by multiplying the current viewpoint height by the change ratio and the minimum change height, that is, the fixed value change height, to calculate the height change amount. Since a new viewpoint height is set by calculating and adding / subtracting the height change amount to the current viewpoint height, the user can set a large number of viewpoint heights (72 levels in this embodiment).

In this case, since the height change amount increases as the viewpoint height increases, the user can set the viewpoint with good operability even when changing the viewpoint from a low height to a high height. Also, at relatively high viewpoint altitudes,
Since the altitude change amount is substantially constant with respect to the current viewpoint altitude, the user can obtain a feeling of ascending or descending the viewpoint in the three-dimensional map display by operating the viewpoint altitude change switch. Then, the user keeps the viewpoint altitude change switch in the operating state,
The three-dimensional map display can be smoothly changed with almost continuous movement.

On the other hand, at a relatively low viewpoint altitude, since the altitude change amount is dominated by the constant value change altitude rather than the ratio change altitude, the user operates the viewpoint height change switch to minimize the viewpoint altitude at least. Only the changing altitude can be changed, and a feeling of rising or falling of the viewpoint of the three-dimensional map display can be obtained. Also, as in the case of a high viewpoint, the three-dimensional map display can be smoothly changed.

Further, the user can operate the viewpoint change switch to set the line of sight upward or downward independently of the setting of the viewpoint altitude. For example, the user can set the viewpoint altitude to be high and change the line of sight to a horizontal plane. By setting the distance slightly lower, the entire street can be displayed, or the far side can be displayed beyond the tall building displayed three-dimensionally. In addition, by setting the line of sight upward, the user can, for example, display a building or an elevated road looking up from the current viewpoint position. By setting the line of sight, the user can obtain more information from the three-dimensional map display.

(Second Embodiment) FIGS. 4 to 6 show a second embodiment of the present invention, in which the same parts as those in the first embodiment are denoted by the same reference numerals and the description is omitted. Only the different parts will be described below. FIG. 4 is a flowchart of the processing for setting the viewpoint height by the screen control management unit 14. Processing steps S7 and S8 are inserted between steps S4 and S5 and step S6.

In step S7, the screen control management unit 1
4 is the viewpoint altitude set in step S4 or S5,
That is, the depression angle in the line-of-sight direction is changed according to the display scale of the map. First, the rate of change N (0 <N <1) of the depression angle θ is set based on equation (4). N = log2 (viewpoint height / minimum viewpoint height) / log2 (maximum viewpoint height / minimum viewpoint height) (4) Here, the minimum viewpoint height and the maximum viewpoint height are, for example, the first viewpoint height.
Are set to 0 m, 600 m, etc., as in the embodiment.
Further, the logarithmic function is used, as in the first embodiment, by setting the viewpoint altitude to increase and the rate of change of the depression angle θ to increase as the map is displayed in a wide area, and the viewpoint altitude to decrease. This is for setting so that the rate of change of the depression angle θ becomes smaller as the map is displayed in detail. Equation (4) determines the curve of the change locus C of the viewpoint position shown in FIG.

When the rate of change N is determined, the depression angle θ is determined by equation (5). θ = N × (maximum depression angle−minimum depression angle) + minimum depression angle (5) Here, the maximum depression angle is, for example, 90 °, and the minimum depression angle is, for example, 1
It is set to 5 ° or the like. As shown in FIG. 5, in a three-dimensional map display, the line-of-sight distance L from the viewpoint to the current position (specific point) indicated by the cursor 15 on the map is given by: L = H · cosec θ ... (6) When the map is displayed two-dimensionally at the same scale, θ =
Since it is 90 °, L = H.

The mark indicating the current position shown in FIG.
The positional relationship between the current position and the viewpoint in FIG. 5 is different from the display when viewed from the viewpoint in the diagram.

In the following step S8, the screen control manager 14 sets the display position Pc of the cursor 15 for displaying the current position on the map using the rate of change N of the depression angle θ as follows. Pc = (Y coordinate of screen center position) × N When the display position Pc of the cursor 15 is set as described above, the current position on the map can be appropriately displayed even when the depression angle changes according to the viewpoint altitude. It becomes.

FIGS. 6A to 6D show examples of changes in screen display on the display unit 6 drawn in step S6a based on the depression angle θ determined as described above. It is a screen display corresponding to positions A to D. As is apparent from FIGS. 6A to 6D, the depression angle θ decreases as the display scale of the map decreases, so that the map can be displayed widely over a long distance in the traveling direction.

A cursor 1 indicating the current position of the car
The display position of No. 5 also gradually moves to the lower side of the screen according to the change of the viewpoint position. And in FIG. 6D,
As shown in the viewpoint position D, the cursor 15 is not displayed on the screen of the display unit 6 because the driver's view is such that the current position and the viewpoint position substantially match. In this case, even if the cursor 15 is not displayed on the screen, the position of the own vehicle can be sufficiently grasped from the shape of the surrounding buildings and the road shape in the traveling direction.

FIGS. 7 and 8 show screen display examples based on the prior art for comparison. For example, FIG. 7 is a constant depression angle of the line of sight direction in the three-dimensional display, as the viewpoint altitude is lower (scales rather small), the viewpoint position is a method in which approaches the current position in the sight-line end. In this case, at the viewpoint A shown in FIG.
Although there is no problem similarly to the above, when the viewpoint altitude decreases from the viewpoint B to the viewpoint D, the display area in the traveling direction gradually narrows, and surrounding buildings and the like are not displayed. In FIG. 7D, the traveling direction and the surrounding buildings are hardly displayed, and only the display of the road is enlarged. Therefore, it is difficult for the driver to grasp the current position of the vehicle. I will.

FIG. 8 shows that the angle of depression in the line of sight in three-dimensional display is constant as in FIG. 7, but the viewpoint position is always vertically above the current position, and the viewpoint position decreases as the viewpoint height decreases. It is a method of descending vertically. In this case, at the viewpoint A shown in FIG. 8A, since the display area is far away from the position of the own vehicle, it is difficult to grasp the relationship with the current position of the own vehicle. From that state, viewpoint B ~
Even when the viewpoint altitude is lowered toward the viewpoint D, the positional relationship between the displayed map and the current vehicle gradually approaches, but it is difficult to grasp, and in FIG. 8D, FIG.
Similarly to the above, the traveling direction and surrounding buildings are hardly displayed, and only the display of the road is enlarged. On the other hand, in FIG. 6, in both the case where the viewpoint altitude is high and the case where the viewpoint altitude is low, the area near the current position of the own vehicle and the area distant from the current position in the traveling direction are displayed in a well-balanced manner. ing.

As described above, according to the second embodiment, the screen control management unit 14 sets the rate of change N of the depression angle θ in accordance with the setting of the line-of-sight altitude according to the equation (4), and sets the depression angle θ to (5 ), The depression angle θ is set to be small when the viewpoint altitude is set low, and the change width thereof is set relatively small, and the depression angle θ is set to be large when the viewpoint altitude is set high, and The width of change is set to be relatively large.

Therefore, both in the case where the viewpoint altitude is high and the case where the viewpoint altitude is low, the area near the current position of the host vehicle and the area far from the current position are displayed on the display unit 6 in a well-balanced manner. The display can be performed so that the user can easily grasp the entire area extending from the viewpoint position to the near and far distances, and at the same time, the map display changes smoothly as the line-of-sight height changes. Can be done.

Further, since the specific point on the map ahead of the line of sight is set as the current position of the own vehicle, even when the map display on the screen changes every moment as in the case of using for car navigation, the screen is displayed on the screen. Since the vehicle is drawn with a line of sight looking down on the current position of the vehicle, the user can easily grasp the current position of the vehicle in the map displayed on the screen.

Further, the screen control management unit 14 changes the display position of the cursor 15 in the screen with respect to the display center coordinates (X, Y) of the screen based on the rate of change N of the depression angle θ by (X, N ·
Y).

That is, the ratio of the display position of the conventional cursor is fixed, for example, the display position is 3: 1 from the top on the Y coordinate of the screen. Therefore, for example, when the depression angle is extremely small as shown in FIG.
On the near side of the screen, the road at the position where the vehicle has already passed and the surrounding buildings are displayed. On the other hand, according to the second embodiment, the display of the current position on the screen can be appropriately set even at a viewpoint close to the driver's view.

The present invention is not limited to the above embodiment, but can be modified or expanded as follows. When the currently set viewpoint altitude is equal to or less than the predetermined altitude, the screen control management unit 14 sets the amount of altitude change every time the viewpoint altitude change switch is operated to only a constant value change altitude (minimum change altitude), If the set viewpoint altitude exceeds the predetermined altitude, a ratio change altitude obtained by multiplying the current viewpoint altitude by a change ratio may be used as the altitude change amount. In this case, the same effect as in the above-described embodiment can be obtained.

The specific point ahead of the line of sight on the map indicated by the cursor 15 is not limited to the current position of the vehicle, but may be set ahead of the current position. The rate of change N such as the depression angle θ is not limited to the equation (4). For example, by determining the rate of change N as N = (viewpoint height) / (maximum viewpoint height), the depression angle may linearly change with respect to the change in viewpoint height. The present invention is not limited to the vehicle navigation device, but can be applied to any device that displays a map three-dimensionally.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a flowchart showing a viewpoint height setting process;

FIG. 3 is a diagram illustrating the relationship between the number of operations of a viewpoint height change switch, the viewpoint height, and the amount of change in height.

FIG. 4 is a view corresponding to FIG. 2, showing a second embodiment of the present invention;

FIG. 5 is a diagram showing a change in a viewpoint position in a three-dimensional display from the side

FIG. 6 is a diagram showing an example of a screen display of a display unit, which is drawn according to each viewpoint position.

FIG. 7 is a diagram corresponding to FIG. 6 according to a change in a conventional viewpoint position (part 1);

FIG. 8 is a diagram corresponding to FIG. 6 according to a change in a conventional viewpoint position (part 2);

FIG. 9 is an explanatory view of a conventional viewpoint height setting.

[Explanation of symbols]

1 is a car navigation device (map display device), 4 is a switch information input unit (input means), 14 is a screen control management unit (screen control management means) , and 15 is a cursor .

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takashi Ichida 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. DENSO Corporation (56) References JP-A-10-143066 (JP, A) JP-A-10- 39747 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01C 21/00-21/36 G08G 1/0969 G09B 29/00-29/10

Claims (6)

(57) [Claims] 1. A map display device having a function of displaying a map three-dimensionally on a screen and displaying a cursor indicating a current position of a vehicle on the map, wherein a viewpoint height at the time of displaying the map three-dimensionally is increased or Input means for inputting a viewpoint height change command for lowering, setting the viewpoint height based on a viewpoint height change command input and operated from the input means, and setting a viewpoint position according to the set viewpoint height. Changing the depression angle in the direction of the line of sight, wherein the input means is operated to the altitude ascending side to increase the viewpoint altitude and increase the rate of change of the depression angle as the map is displayed in a wide area. And setting the cursor at the display position where the display position of the cursor indicating the current position of the vehicle on the map is gradually moved to the upper side of the screen. A display is performed together with the three-dimensional map viewed from the viewpoint position at a fixed viewpoint height, and the rate of change of the depression angle decreases as the input means is operated on the lowering side to lower the viewpoint height and the map is displayed in detail. The depression angle is set so that the display position of the cursor indicating the current position of the vehicle on the map is gradually shifted to the lower side of the screen. When the input means is operated and the current position of the vehicle substantially matches the viewpoint position, the map to be displayed three-dimensionally is displayed as a driver's view and the cursor is displayed. A map display device comprising: a screen control management unit for hiding a display. 2. The method according to claim 1, wherein the three-dimensionally displayed map has a viewpoint
To the current position indicated by the cursor on the map
The map display device according to claim 1 , wherein the line distance L is a value satisfying L = H · cosec θ, where θ is the depression angle and H is the viewpoint altitude . 3. The map display device according to claim 1, wherein the screen control management means can set the line of sight upward or downward independently of the setting of the viewpoint altitude. 4. The screen control management means calculates the depression angle θ indicating the line-of-sight direction as follows: θ = N × (maximum depression angle−minimum depression angle) + minimum depression angle N = log2 (viewpoint height / minimum viewpoint height) / log2 claims 1 and sets based on the viewpoint altitude / Min viewpoint altitude) 3
The map display device according to any one of the above. 5. A specific point on the map in the viewing direction destination, map display apparatus according to any one of 4 to claims 1, characterized in that in front of the current position or the current position on the map . 6. The screen control management means sets coordinates indicating the display center of the screen to (X, Y) and sets a change rate N as N = log2 (viewpoint height / minimum viewpoint height) / log2 (maximum viewpoint height / The map display device according to any one of claims 1 to 5 , wherein the display position of the cursor is set by (X, N, Y), where (minimum viewpoint altitude).