JP2671393B2 - Map information display device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a map information display device applied to a navigation system, and more particularly to a data structure of map information stored in a storage device such as a CD-ROM.

[Summary of the Invention]

In the present invention, the map information is stored in the storage device, the map information is read from the storage device, and is displayed on the display device. In the map information display device, the map information is composed of a plurality of maps at a plurality of scales. Further, each of the plurality of maps has a plurality of display hierarchy levels, and the display device selects any one of the plurality of maps according to the display magnification and sets the display magnification of the selected map to a predetermined magnification. ,and,
By displaying a predetermined hierarchy among the display hierarchy levels according to the display magnification, it is possible to reduce the amount of data to be prepared, access at high speed, and continuously change the magnification.

[Prior art] As one of navigation systems, a self-contained navigation system that displays a map and the position of the vehicle on the screen of a CRT display is being put to practical use, and in the future, a method that also uses position information outside the vehicle Is also considered. The map information is stored in a storage device such as a CD-ROM. Conventionally known map databases prepare maps at stages according to the degree of detail. For example, national maps, local maps,
A method has been proposed in which a five-step map of a district map, a basic map, and a detailed map is prepared. Selection of these map stages is possible by operating switches.

[Problems to be solved by the invention]

The above-mentioned map data structure has a problem that the type of map magnification (scale) is restricted. The map magnification is preferably any magnification desired by the user. If you try to realize an arbitrary magnification with the conventional data structure,
It is necessary to provide a large number of stages as the level of the map, and as a result, not only the amount of data becomes enormous, but also the number of accesses increases and high speed operation cannot be performed.

Therefore, an object of the present invention is to provide a map information display device capable of changing the magnification continuously or in fine steps without causing problems such as a large amount of data to be prepared and slow access or low speed. It is in.

[Means for solving the problem]

In the present invention, the map information is stored in the storage device, the map information is read from the storage device, and is displayed on the display device. In the map information display device, the map information is composed of a plurality of maps at a plurality of scales. Further, each of the plurality of maps has a plurality of display hierarchy levels, and the display device selects any one of the plurality of maps according to the display magnification and sets the display magnification of the selected map to a predetermined magnification. ,and,
A predetermined layer among the display layer levels is displayed according to the display magnification.

[Action]

The map information stored in a storage device such as a CD-ROM is composed of a plurality of maps, for example, three maps according to the magnification. These maps are referred to as a 0th-order mesh, a 1st-order mesh, and a 2nd-order mesh in order from the one with the smaller magnification, that is, the one with the larger range displayed on the CRT display. The data of each mesh is divided into a plurality of, for example, 10 hierarchical levels (0 to 9) according to the display priority.

When the display magnification is changed by operating a switch such as the zoom key, the 0th-order mesh data is used in the small magnification range, the 1st-order mesh data is used in the intermediate magnification range, and the high magnification range is used. In, the data of the secondary mesh is used. Since the data is divided for each mesh at the hierarchical level, display / non-display control is performed according to the hierarchical level when the magnification changes within the range in which the data of each mesh is used. The display magnification is
It is possible to change continuously by data processing, and as the display magnification increases and the level of detail increases, information of lower priority is displayed in addition to information of higher priority. In this way, since the data of each mesh is divided at the hierarchical level, it is possible to change the magnification continuously or in fine steps with a small amount of data and at high speed.

〔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, reference numeral 1 indicates a data bus, and a microcomputer 2 is coupled to the data bus 1. The microcomputer 2 is also supplied with an output signal from the vehicle sensor 3. As the vehicle sensor 3, a geomagnetic sensor (which detects an absolute azimuth),
A vehicle speed sensor (which detects a traveling distance), a steering sensor (which detects a traveling direction), a transmission sensor (which detects forward and backward movements), and the like are used.

Also, a CD-ROM driver indicated by 4 is provided
The map data stored in 5 is given to the microcomputer 2 via the CD-ROM driver 4 and the data bus 1. Further, an operation switch 9 that can be operated by the driver is provided.

The data from the microcomputer 2 is supplied to the drawing processor 6, the drawing processor 6 forms image data, and the drawing data is supplied to the color CRT display 8. Although not shown, D / A to which image data is supplied
A converter is provided and the color CRT display 8 is supplied with analog RGB output image signals. The color CRT display 8 is mounted on the car dashboard.

The operation switch 9 has the configuration shown in FIG.
Reference numeral 11 denotes a cursor key. The cursor key 11 moves the cursor on the map screen to scroll the screen, and the cursor is used to select a function. 12A
Indicates a zoom-in key, and 12B indicates a zoom-out key. By pressing the 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 denotes a function key. With the function key 13, various functions such as selection of an item to be displayed, setting of a destination and search of a destination are displayed in a menu format on a part of the screen, for example, on the right side, and the menu is a cursor. It is selected by the key 11. 14
Indicates a set key, and the set key 14 is pressed when the 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 or not the cursor has moved (step 21). When the cursor has not moved, it is determined whether the position of the vehicle has moved (step 22). When the position of the vehicle has not moved, it is determined whether the zoom key 12A or 12B has been pressed (step 23).

When the cursor moves or the vehicle moves,
It is determined whether adjacent map data is needed (step
twenty four). When the adjacent data is not required, a drawing operation for displaying a map on the color CRT display 8 is performed (step 26). When the adjacent data is required, the map data is read from the CD-ROM 5 (step 25) and the drawing operation (step 26) is performed. After the drawing operation, the step of determining whether the zoom key 12A or 12B is pressed
Move to 23.

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

Vector data, character data, and font data are recorded on the CD-ROM 5. FIG. 4 shows the format of these data recorded on the CD-ROM 5.

The vector data is recorded on the CD-ROM 5 in units of the record shown in FIG. 4A for each link of the line drawing.
As shown in FIG. 4B, the line drawing is expressed as a link which is a set of a plurality of straight lines. That is, coordinate data (X) indicating the coordinates of the start and end positions of each of the plurality of straight lines.
(1), Y (1)), (X (2), Y (2)), ... Are included in the vector data. Also, 1 of vector data
Records are type, link number, sub type, route number,
It consists of a hierarchy level, the number of interpolation points, and coordinate data. The type indicates the type of road such as national road, toll road, general road,
The sub-type indicates a fine type according to the type such as the rank of a national road, and the route number indicates a fine classification for each type such as a number attached to a road. The link number is a link number, and the hierarchy level is numerical data (0 to 9) corresponding to the display priority. Further, the number of interpolation points represents the number of start and end points in the link (for example, 6 in the example of FIG. 4B).

FIG. 4C shows the format of character data. The character data includes a type, subtype, serial number, hierarchy level, normalized coordinates (X, Y), number of Kanji words, and Kanji character string. The type is, for example, data for distinguishing an intersection name, a place name, a facility name, and a railway station name. The subtype is data for subclassification for each type. The serial number is a number within each type. The normalized coordinates are coordinate data indicating a position where a character is displayed, the hierarchical level is data indicating the same display priority as described above, and the Kanji word number is the number of Kanji. Further, the kanji character string is a standardized character code.

The font data has the format shown in FIG. 4D,
It is described in CD-ROM5. The type is data for distinguishing the type of font. For example, a highway number, a national road number, a main road number, a parking lot, 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 for indicating the display position of the font.

As shown in Fig. 5, CD-ROM5 has 3 different magnifications.
Individual map data is stored. These three pieces of data are referred to as a 0th-order mesh, a 1st-order mesh, and a 2nd-order mesh in order of increasing length of one side of the displayed map.

For the 0th-order mesh, map 30 of the area where one side is a
There are 3 files. Data is read from the CD-ROM 5 in units of files. The primary mesh is
One file is a map 31 (indicated by diagonal lines) 31 in which one side a of the map 30 is divided and one side has a length of b. For example, the map 31 has a size obtained by dividing the vertical and horizontal lengths of the map 30 into (1/16) each. The secondary mesh has a map 32 (indicated by diagonal lines) 32, which is an area obtained by dividing one side b of the map 31 and has one side c, as one file. For example, map 32 is the size obtained by dividing the vertical and horizontal lengths of map 31 into (1/16) each.
Has. One of these maps 30, 31, 32 is a CD-RO
The data is read from M5, processed by the drawing processor 6, and then displayed on the screen of the color CRT display 8.
4 files for each map to realize the scroll function
The configuration may be divided.

Zoom in (enlarge) and zoom out (reduce)
Is realized by the process of multiplying the vector data of the map by a coefficient corresponding to the enlargement or reduction ratio. This processing is performed by the drawing processor 6. When the map 30 of the 0th mesh is enlarged by zooming in and becomes the size of the map 31 of the size of the 1st mesh, the map 1 of the 0th mesh is
The map level is changed to the next mesh. That is, the map 31 of the primary mesh is read from the CD-ROM 5. When the map 31 of the primary mesh is enlarged by the zoom-in operation and becomes the size of the map 32 of the size of the secondary mesh, the level of the map data is changed from the primary mesh to the secondary mesh. Further, when a zoom-in operation is performed, a map having a size of d on each side is displayed. The zoom-out operation is performed in the opposite direction to the zoom-in operation described above.

The map is 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 0 to 9 are set, and data indicating the hierarchical level is added to each record of the data stored in the CD-ROM 5. (See FIG. 4).

As described above, the 0th-order, 1st-order, and 2nd-order meshes are switched, that is, the map level is changed by the zoom-in operation or the zoom-out operation. Within each mesh, the level of hierarchy is changed. For example, in the primary mesh, the size is changed in the expanding direction in which the length of one side is further reduced by the zoom-in operation from the map 31 with one side being b in size, so that the hierarchical level is 0. It is changed sequentially from 9 to 9. The hierarchy level is similarly changed for the other 0th-order meshes and the 2nd-order meshes. In FIG. 6, an area inside the graph means a displayed hierarchy level, and an area outside the area means a displayed hierarchy level. The hierarchy levels 0 to 9 correspond to the display priorities such that 0 has the highest display priority and the display priority decreases as the number increases.

The change of the hierarchical level in the mesh will be described with reference to FIG. The horizontal axis of FIG. 7 shows the magnification as a logarithm, and in FIG. 7, it has a range of change of 1 to 50. The larger the magnification, the larger the map will be displayed. 33
A, 33B, and 33C indicate threshold values for display and non-display, respectively. The threshold value 33A is a threshold value used when the display density is the lowest, and the threshold value 33B shown by a broken line is a threshold value used when the display density is in the middle.
C is the threshold value used at the highest display density. The display density can be arbitrarily set by operating the cursor key 11 and the function key 13 in the operation switch 9.

The upper side of these thresholds represents the displayed hierarchy level and the lower side of these thresholds represents the hidden range. The displayed hierarchy level increases as the magnification increases. For example, when the display density is low, the data of the hierarchy level 0 is displayed in the range of the smallest magnification, and when the display density is the middle, the hierarchy level 0 is displayed.
When the display density is high, the data of hierarchical levels 0, 1 and 2 are displayed.

Since the displayed hierarchy level changes depending on the magnification, the amount of information displayed on the map screen of the color CRT display 8 increases as the zoomed-in key 12A is continuously pressed and the displayed map is enlarged. To a higher degree. For example, when a zoom-in operation is performed, smaller roads are displayed in addition to the main roads, and details of interchanges on highways are displayed. Information other than roads,
What is displayed increases 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.

Display density: 0 (low), 1 (middle) or 2 (high) S: Length of one side of map displayed on screen l: Length of one side stored as map data 5.8859: Slope An example of constants for causing generation Note that the present invention can be applied to a map information display device other than the navigation system. The storage device is not limited to the CD-ROM, and a floppy disk or the like may be used.

〔The invention's effect〕

According to the present invention, unlike the conventional case where the maps of a plurality of levels corresponding to the magnification are prepared, it is not necessary to duplicately store the data in the storage device between the maps of different magnifications, and the data amount can be reduced. It can be prevented from increasing. The present invention has an advantage that the magnification can be easily changed continuously or in fine steps, and the problem that the operation speed becomes slow due to the increase in the number of accesses does not occur.

[Brief description of the drawings]

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 flow chart used to explain the operation of the navigation system, and FIG. A schematic diagram used to explain the structure of the data stored in the CD-ROM, FIG. 5 is a schematic diagram used to describe the map data recorded on the CD-ROM, and FIGS. 6 and 7 are maps. It is an approximate line figure used for explaining a hierarchy level of data. Description of main symbols in the drawings 5: CD-ROM, 9: operation switch, 11: cursor key, 12A: zoom-in key, 12B: zoom-out key.

Claims (1)

(57) [Claims] 1. A map information display device in which map information is stored in a storage device, the map information is read from the storage device, and is displayed on a display device, wherein the map information includes a plurality of scales at a plurality of scales. Each of the plurality of maps has a plurality of display hierarchy levels, and the display device selects one of the plurality of maps according to a display magnification and a display magnification of the selected map. Is set to a predetermined magnification, and a predetermined hierarchy of the display hierarchy levels is displayed according to the display magnification.