JPH024285A - Device for displaying map information - Google Patents

Abstract

PURPOSE:To reduce data quantity which should be prepared, to make access at high speed and to continuously change magnifications by constituting map information of plural magnifications and plural maps corresponding to the magnifications, dividing the maps into plural hierarchical levels corresponding to the priority degree of displays and switching the maps and the hierarchical levels according to the magnifications. CONSTITUTION:The map information is constituted of plural magnifications and plural maps corresponding to the magnifications. The maps are divided into plural hierarchical levels corresponding to the priority degree of the displays. The maps and the hierarchical levels are switched in response to the magnifications. Thus, data is divided by the hierarchical levels at every mesh. When the magnification is changed in a range where data of each mesh is used, the maps are controlled to be displayed or not according to the hierarchical levels. As the magnification of the display becomes bigger and the degree of details increases, information whose priority degree is low is successively displayed as well as information whose priority degree is high. Therefore, data quantity can be reduced and the magnifications can be changed continuously or by fine steps at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a map information display device commonly used in navigation systems, particularly a storage device such as a CD-ROM.
This relates to the data structure of map information stored in .

[Summary of the invention]

In this invention, in a map information display device that stores map information in a storage device, reads out the map information from the storage device, and displays it on a display device, the map information is displayed on a plurality of sheets corresponding to a plurality of magnifications. Each map is divided into multiple hierarchical levels depending on the display priority, and the map and hierarchical level can be switched depending on the magnification, reducing the amount of data that needs to be prepared and increasing speed. Access and continuous magnification changes are possible.

[Prior art] As one type of navigation system, an autonomous navigation system that displays a map and the location of your own troops on a CRT display screen is being put into practical use. It is considered. The map information is stored in a storage device such as a CD-ROM. Conventionally known map databases prepare maps of different levels depending on the level of detail. For example, a method has been proposed in which five levels of maps are prepared: national map, regional map, district map, basic map, and detailed map. The selection of these map stages is
This is possible by operating a switch, etc.

[Problem to be solved by the invention]

The above-mentioned map data structure has a problem in that the type of map magnification (scale) is restricted. Preferably, the map magnification is any magnification desired by the user. If an attempt was made to achieve an arbitrary magnification using the conventional data structure, it would be necessary to set up a large number of map levels, which would result in not only a huge amount of data but also an increase in the number of accesses. , a problem arises in which high-speed operation is not possible.

Therefore, an object of the present invention is to provide a map information display device that can change the magnification continuously or in small steps without causing problems such as an increase in the amount of data to be prepared or slow access. It is in.

[Means to solve the problem]

In this invention, in a map information display device that stores map information in a storage device, reads out the map information from the storage device, and displays it on a display device, the map information is displayed on a plurality of sheets corresponding to a plurality of magnifications. Each map is divided into a plurality of hierarchical levels depending on the display priority, and the maps and hierarchical levels are switched according to the magnification.

(Operation) Map information stored in a storage device such as a CD-ROM is
It consists of a plurality of maps, for example three, depending on the magnification. These maps are divided into 0-order mesh, 1-order mesh, and
This is called a secondary mesh or a secondary mesh. The data of each mesh is classified into a plurality of hierarchical levels, for example, ten hierarchical levels (0 to 9), depending on the display priority.

When the display magnification is changed by operating a switch such as the zoom key, 0-order mesh data is used in the range where the magnification is small, data from the 1st-order mesh is used in the range where the magnification is intermediate, and data in the high-magnification range is used. In this case, the data of the secondary mesh is used.

Since data is divided into hierarchical levels for each mesh, when the magnification changes within the range in which the data of each mesh is used, display/non-display is controlled according to the hierarchical level. The display magnification can be changed continuously through data processing, and as the display magnification increases and the level of detail increases, low-priority information is sequentially displayed in addition to high-priority information. . In this way, since the data of each mesh is divided at hierarchical levels, it is possible to change the magnification continuously or in small steps with a small amount of data and with high speed operation.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a navigation system to which the present invention can be applied. In FIG. 1, 1 indicates a data bus, and a microcomputer 2 is connected to the data bus 1.
are combined. Further, the microcomputer 2 is supplied with an output signal from the vehicle sensor 3 . As the vehicle sensor 3, a geomagnetic sensor (detects the absolute direction), a vehicle speed sensor (detects the distance traveled), a steering sensor (detects the direction of travel), a transmission sensor (detects forward and backward movement), etc. are used. Ru.

In addition, a CD-ROM driver indicated by 4 is provided, and a CD-ROM driver is provided.
-Map data stored in ROM5 is CD-ROM
It is applied to the microcomputer 2 via the driver 4 and data bus l. Furthermore, an operation switch 9 that can be operated by the driver is provided.

Data from the microcomputer 2 is supplied to a drawing processor 6, which forms image data and supplies the drawing data to a color CRT display 8. Although not shown, there is a D/ to which image data is supplied.
An A converter is provided, and the color CRT display 8 is supplied with an analog RCB small output image signal. The color CRT display 8 is attached to the dash board of the car.

The operation switch 9 has the configuration shown in FIG. 1
1 indicates a cursor key, and by using the cursor key 11,
The cursor moves on the map screen, the screen is scrolled, and functions are selected using the cursor. 12
A indicates a zoom in key, and 12B indicates a zoom out key. By pressing zoom in key 12A,
The map screen is enlarged, and by pressing the zoom out key 12B, the map screen is reduced. Reference numeral 13 indicates a function key. By using the function key 13, various functions such as selecting an item to be displayed, setting a destination, and searching for a destination are displayed in menu form on a part of the screen, for example on the right side, and the menu is displayed when the cursor is placed. By key 11,
selected. Reference numeral 14 indicates a set key, and the set key 14 is pressed when a function selected by the cursor key 11 is executed.

FIG. 3 is a flowchart used to explain the operation of the navigation system described above. First, it is determined whether the cursor has moved (step 21). When the cursor has not moved, it is determined whether the vehicle position has moved (step 22), and when the vehicle position has not moved, it is determined whether the zoom key 12A or 12B has been pressed (step 22). 23).

When the cursor moves or the vehicle moves, it is determined whether adjacent map data is required (step 2).
4). When adjacent data is not required, a drawing operation is performed to display a map on the color CRT display 8 (step 26). When adjacent data is required, CD-RO
Map data is read from M5 (step 2
5), a drawing operation (step 26) is performed. After the drawing operation, the process moves to step 23 in which it is determined whether the zoom key 12A or 12B has been pressed.

When the zoom key 12A or 12B is pressed, it is determined from the zoom magnification whether the map level needs to be changed (step 27). When the map level does not need to be changed, a drawing operation (step 29) is performed to display the map on the color CRT display 8. When it is necessary to change the map level, after the map data is read from the CD-ROM 5, the process moves to a drawing operation (step 29). When zoom key 12A or 12B is not pressed or drawing operation (
After step 29), the process returns to step 21 and the same operations as described above are repeated.

Vector data, character data, and font data are recorded on the CD-ROM 5. Figure 4 shows CD-R
The format of these data recorded in OM5 is shown.

The vector data is recorded on the CD-ROM 5 in units of records shown in FIG. 4A for each link of the line drawing. As shown in FIG. 4B, the line drawing is expressed as a link that is a collection of a plurality of straight lines. In other words, coordinate data (
X(1), Y(1)).

(X (2), Y (2)), ... are included in the vector data. Further, the vector data code includes type, link number, subtype, route number, hierarchy level, number of interpolation points, and coordinate data. The type is national highway,
Represents the type of road such as national road, -ship road, etc., sub-type represents a more detailed type than the rank of national highway, etc., and route number represents a subdivision of each type such as the number attached to the road. .

The link number is the number of the link, and the hierarchy level is numerical data (0 to 9) corresponding to the display priority. Furthermore, the number of interpolation points is determined by the number of starting and ending points within the lick (
For example, in the example of FIG. 4B, 6) is represented.

FIG. 4C shows the format of character data.

The character data consists of type, subtype, serial number, hierarchy level, normalized coordinates (X, Y), number of Kanji words, and Kanji character string. The type is data for distinguishing, for example, an intersection name, a place name, a facility name, or a railway station name.

The sub-type is data for subdividing each type. The serial number is a number within each type. The normalized coordinates are coordinate data indicating the position where a character is displayed, the hierarchy level is data indicating the display priority similar to the above, and the number of Kanji words is the number of Kanji characters. Furthermore, the kanji string is
It is a standardized character code.

The font data is in the format shown in Figure 4.
It is recorded in D-ROM5. The type is data for distinguishing the type of font.

For example, expressway numbers, national highway numbers, major road numbers, parking lots, etc. are distinguished by type. The font number is a number that specifies a font pattern, and the serial number is, for example, a serial number added in the order of creation. The normalized coordinates are data indicating the position where the font is displayed.

As shown in FIG. 5, the CD-ROM 5 stores three pieces of map data with different magnifications.

These three pieces of data are called a 0th-order mesh, a 1st-order mesh, and a 2nd-order mesh in descending order of the length of one side of the displayed map.

The 0th-order mesh is the map 30 of the region with side length a.
It is a separate file. Data is read from the CD-ROM 5 in file units. In the primary mesh, one file contains a map 31 (indicated by diagonal lines) having an area of length b obtained by dividing one side a of the map 30. For example, the length and width of the map 30 are each (1/16
) The map 31 has a divided size. In the secondary mesh, one file contains a map 32 (indicated by diagonal lines) in which one side of the map 31 is divided into regions having a length of C. For example, the vertical and horizontal lengths of the map 31 are each (1/1
The map 32 has a size divided into 6). One of these maps 30, 31, 32 is read out from the CD-ROM 5, processed by the drawing processor 6, and then displayed on the screen of the color CRT display 8. In order to realize the scrolling function, each file of the map may be divided into four parts.

The aforementioned zoom-in (enlargement) and zoom-out (reduction) are realized by multiplying the vector data of the map by a coefficient corresponding to the magnification of enlargement or reduction. This processing is performed by the drawing processor 6. When the zero-order mesh map 30 is enlarged by a zoom-in operation and reaches the size of the first-order mesh map 31, the geological level is changed from the zero-order mesh to the first-order mesh. That is, the primary mesh map 31 is read from the CD-ROM 5. When the primary mesh map 31 is enlarged by a zoom-in operation and becomes the size of the secondary mesh map 32,
The level of the map data is changed from the primary mesh to the secondary mesh. Furthermore, when zooming in, the − side becomes d
A map of the size is displayed. The zoom-out operation is performed in the opposite direction to the zoom-in operation described above.

Maps are switched at these three levels, and the hierarchy level is changed at each level according to the magnification. As shown in FIG. 6, in this example, 10 hierarchical levels from O to 9 are set, and data indicating the hierarchical level is added to each record of data stored in the CD-ROM 5. (See Figure 4).

As described above, the zoom-in or zoom-out operation switches between zero-order, first-order, and second-order meshes, that is, changes in the map level.

Within each mesh, hierarchical level changes are made. For example, in a first-order mesh, a map 31 whose − side is of size b
Due to the zoom-in operation, the size is changed in the direction of enlargement in which the length of the - side becomes smaller, and the hierarchical levels are sequentially changed from O to 9. Hierarchical levels are similarly changed for other zero-order meshes and second-order meshes. In FIG. 6, the area inside the graph represents a hierarchical level that is displayed, and the area outside thereof represents a hierarchical level that is not displayed. The order of the hierarchy levels from O to 9 corresponds to the display priority such that 0 has the highest display priority, and as the number increases, the display priority decreases.

Changing the hierarchical level within a mesh will be explained with reference to FIG. The horizontal axis of FIG. 7 shows the magnification as a logarithm, and in FIG. 7, the map has a variation range of 1 to 50. The larger the 0 magnification, the more enlarged the map is displayed. 3
3A, 33B, and 33C indicate display and non-display thresholds, respectively. The threshold value 33A is the threshold value used when the display density is the lowest, and the threshold value 33B is indicated by a broken line.
is the threshold used when the display density is intermediate,
The threshold value 33C is the threshold value used when the display density is highest. The display density can be arbitrarily set by operating the cursor keys 11 and function keys 13 in the operation switch 9.

The upper side of these thresholds represents the hierarchical level of the range that is displayed, and the lower side of these thresholds represents the hierarchical level of the range that is not displayed. As the magnification increases, the number of hierarchical levels displayed increases.

For example, in the range where the magnification is the smallest, when the display density is low, data at hierarchy level 0 is displayed, when the display density is intermediate, data at hierarchy levels 0 and 1 is displayed,
When the display density is high, data of hierarchy levels O, I, and 2 are displayed.

Because the displayed hierarchy level changes depending on the magnification,
As the zoom in key 12A continues to be pressed and the displayed map is enlarged, the amount of information displayed on the map screen of the color CRT display 8 increases and the degree of detail increases. For example, when a zoom-in operation is performed, a smaller road other than a main road is displayed, or details of an expressway interchange are displayed. Information other than roads,
The items displayed increase as the hierarchy level increases.

The hierarchy level shown in FIG. 7 is determined, for example, by taking the integer value of the following formula.

Hierarchy level! = Display density + (log + o ()) X5.885
9 Display density: 0 (low), l (medium) or 2 (high) S: Length of one side of the map displayed on the screen! : Length of one side held as map data 5.8859 : Example of a constant for creating a tilt Note that the present invention can also be applied to map information display devices other than navigation systems. In addition, as a storage device, CD-
In addition to ROM, a floppy disk or the like may also be used.

〔Effect of the invention〕

According to this invention, unlike the conventional method of preparing maps with multiple levels corresponding to different magnifications, there is no need to have duplicate data in the storage device for maps with different magnifications.
It is possible to prevent the amount of data from becoming large. This invention has the advantage that it is easy to vary the magnification continuously or in small steps, and there is no problem of slowing down the operation speed due to an increase in the number of accesses.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an example of a navigation system to which the present invention can be applied, Fig. 2 is a front view showing an example of the arrangement of operation switches, Fig. 3 is a flowchart used to explain the operation of the navigation system, and Fig. 4 is a CD-RO
Figure 5 is a route map used to explain the structure of data recorded on CD-ROM. Figures 6 and 7 are map data hierarchy levels. It is a route map used for explanation. Explanation of main symbols in the drawings 5 F CD-ROM, 9: Operation switch, 11: Cursor key, 12A: Zoom in key 12B: Zoom out key Agent Patent attorney Tadashi Sugiura Diagram 1 Operation switch/rich layout No. Fig. 2 Fig. 4 Fig. 3 Flowchart Fig. 5

Claims (1)

[Scope of Claim] A map information display device that stores map information in a storage device, reads out the map information from the storage device, and displays it on a display device, wherein the map information has multiple magnifications and Consisting of a plurality of corresponding maps, each of the maps is divided into a plurality of hierarchical levels according to the display priority, and the map and the hierarchical level can be switched according to the magnification. A display device for map information.