JPS62151715A - Vehicle navigation device - Google Patents

Abstract

PURPOSE:To display map information on many scales with a simple constitution by transferring only part of map information in a specific range which is stored on the 1st memory to the 2nd memory and drawing it on a different scale. CONSTITUTION:Respective pieces of map information on the 1st scale, e.g. 1/800,000, 1/200,000-1/12,500 are stored on a storage medium 1. A memory 5 stores map information on the scale which is read out of the medium 1 and includes a current position. A controller reads at least part of the map information out of the memory 5 and draws its image on readout memories 16 and 17. A display device displays the map information stored on the memories 16 and 17. In this case, the controller transfers the map information on the memory 5 to the memories 16 and 17 as it is within a specific range to draw the map information on the 1st scale. On the other hand, only part of the map information within the specific range is transferred to the memories 16 and 17 and drawn as pieces of map information on the 2nd scales, e.g. 1/1,600,000, 1/400,000-1/20,000. Therefore, the number of maps on respective scales stored previously on the storage medium 1 may be small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle navigation device that displays map information on a display device and guides a vehicle to a predetermined destination.

[Summary of the invention]

The present invention provides a vehicle navigation device that includes a current location detection means for detecting the current location of a vehicle, a storage medium that stores map information of a first scale, and map information of the first scale that includes the current location read from the storage medium. A controller that reads at least part of map information from the first memory and draws it on a second memory, and a display device that displays the map information stored in the second memory. .

The controller directly transfers the map information in the first memory for a predetermined range to the second memory.

While drawing the map information of the first scale, only a part of the map information within the predetermined range is transferred to the second memory, and the map information of the second scale different from the first scale is drawn. This allows map information of more scales to be displayed with a simple configuration.

[Conventional technology]

Recently, a vehicle navigation system has been researched and developed that records map information on a storage medium such as a CD-ROM, reads out the map information, displays it on a display device along with the vehicle's current location, and guides the vehicle to a predetermined destination. has been done. In such a device, maps of a plurality of scales are recorded in advance on a storage medium so that map information of different scales can be displayed as necessary.

[Problem that the invention seeks to solve]

However, since the conventional apparatus stores each map of the necessary scale in a storage medium, the capacity of the storage medium must be increased, and it is not only impossible to downsize the apparatus.

It had the disadvantage of being expensive.

[Means for solving problems]

FIG. 1 is a block diagram of a vehicle navigation system according to the present invention. In the figure, reference numeral 1 denotes a CD-ROM (including its drive device) as a recording medium or storage medium, on which digitized map information is recorded. CD
-Data from ROMI is transferred to memory (RAM) 5 via interface 2, address bus 3, data bus 4, etc.
is stored in the memory. Reference numeral 6 denotes an information processor (CPU), which processes various image data and also operates the keyboard 12 . Peripheral devices are also controlled in response to commands input via the interface 13. Reference numeral 7 indicates a direction sensor that detects the direction of the vehicle from geomagnetism or the like, and reference numeral 8 indicates a speed sensor that detects the speed of the vehicle. 9 is GPS (Global Po
This is a device that detects the current location of a vehicle from latitude, longitude information, etc. 10 is a navigation processor (CPU), which corrects data from the direction sensor 7, speed sensor 8, etc., calculates the amount of movement of the vehicle from these data, and also uses the GPS device [
9 calculates the current position from the input data when latitude and longitude information cannot be detected. Alternatively, the current location that has been set and input is corrected in accordance with information from the GPS device 9. The processor 10 and the processor 6 are capable of mutually transmitting and receiving data. Reference numeral 11 represents a ROM for storing programs and other necessary information for the processors 6 and 10, and reference numeral 14 represents a control logic for supplying necessary timing signals to each circuit 1 means, device, etc.

15 is a graphic display controller (G D
C), the necessary data is read from the memory 5 and a predetermined image is drawn in the memory (VRAM) 16, 17.

, 18 is a parallel/serial (P/S) conversion circuit that selects data from one of the memories 16 and 17 and converts it from a parallel signal to a serial signal. A color palette register 19 serves as a color conversion circuit, and converts the 3-bit color signal in the video signal supplied from the P/S conversion circuit 18 into a prespecified 5-bit color signal. The video signal into which the color signal has been converted is transferred to the memory (VRAM) 20, and from the memory 20 to the memory (VRAM) 21, and the video signal stored in the memory 21 is transferred to red (R), green (G), blue ( B) D/A conversion circuit 26 for each of the three primary colors.
The digital signal is converted into an analog signal by 27.28.

It is displayed on a display device 29 such as a CRT. Although not shown, a touch sensor made of a transparent electrode or the like is provided on the front surface of the screen of the display device 29.

24 is a synchronization signal generation circuit, which generates a mutually synchronized horizontal synchronization signal (H8YNC) and vertical synchronization signal (VSYNC).
, generates a dot clock (DCK) and registers 19.
．． It outputs to address counters 23, 25, etc., which set the addresses of the memory 20, 21, etc. 22 is an offset register, which sets the offset position of the portion of the image stored in the memories 16 and 17 to be transferred to the memory 20. 30 to 37 are buffers inserted at predetermined positions, respectively.

On the other hand, FIG. 2 shows the structure of the keyboard 12. As shown in the figure, each operation key is arranged on the outer periphery of the display device 29. 51 is a navigation (NAVI) key operated when performing a navigation operation; 52 is a help key operated when outputting an operation explanation image to the display device 29; 53 is a guide (GUIDE) key; , is operated when displaying symbols such as parking lots, hotels, gas stations, etc. on the map. 54 is a destination (DEST) key, which is operated when setting a destination. 55 is a SET key. and display device 2
It is operated when registering the item specified by the cursor displayed at 9 or the position on the map. Reference numeral 56 denotes a CANCEL key, which, when operated on a limited number of predetermined screens, returns one screen to the previous screen. 57 is a reduction key, and 58 is an enlargement key, each of which is operated to reduce or enlarge the map displayed on the display device 29. 59 is a scroll key, and keys 59a to 59d are used to move the cursor up and down, left and right, respectively.
is manipulated. Reference numeral 60 denotes a text (TEXT) key, and the program is managed by the processor 6 when each of the 0 or more keys operated to display information related to the running of the vehicle is operated.

A CD key 61 that is operated when operating a five-way compact disc player, a TV key 62 that is operated when receiving television broadcasting, an AM and FM key 63 that is operated when receiving AM or FM broadcasting, and a key that controls the playback sound. Sound select (SOUND 5EL) key 64, which is operated when selecting an equalization characteristic from among predetermined characteristics. A muting key 65 that instantly mutes the playback sound, a volume 66 that adjusts the volume of the playback sound,
An air conditioning (A/C) key 67 is provided to be operated when operating the air conditioner, and a predetermined operation is executed by a CPU (not shown).

[Effect]

The effect will now be explained. First, the basic operation when the navigation key 51 is operated will be explained. The operations in this case are managed according to a flowchart as shown in FIG. 3, for example. As a first step, it is determined whether the current location has been set. When the current location has already been set, a display routine is executed, and when it has not been set, a current location setting routine is executed. These routines will be described later.

Next, the system enters a key wait state, and if there is no key power, the display routine is further executed, and then the key enters the wait state again.

If there is a key human power, next it is determined whether there is a mode change,
When a mode change occurs, the routine shifts to that mode. Modes include navigation mode, text mode, AV mode, etc. When there is no mode change, commands are determined and routines such as destination setting, drive guide, help, scaling, correction, and position output are executed in response to the command. Thereafter, the system returns to the state of waiting for the key force, and the display routine is executed until the key force is applied.

The routine for setting the current location is executed according to the flowchart shown in FIG. First, cancel key 56
The presence or absence of an operation is determined, and when the operation is performed, the current current location is reset, and a predetermined predetermined position is set as a temporary current location. Further, the scale of the map is set to a predetermined value (1/1.6 million in this case). A map centered on the predetermined location is then displayed on the display device 29.

When the cancel key 56 is not operated, it is then determined whether the current location has been set.

If the current location has been set, a map of a preset scale (1/20,000 in this example) centered around the current location is displayed on the display device 29. If the current location has not been set, a predetermined location is set as the temporary current location, and a map of a predetermined scale (1/200,000 in this example) centered at that location is displayed.

When the map is displayed on the display device 29, the input key is then determined, and processes such as setting the scale, moving the cursor, setting, setting the place name guide, and canceling are performed in response to the input key. When the cancel key 56 is operated, the process returns to the first step. When the set key 55 is operated, it is further determined whether or not the center position is to be set. If the center position is not set, the scale specified by the cursor is set, and a scale set is executed to display a map of that scale. If it is a set of center positions,
In the same way as when the place name and guide set key 53 is operated, the current location is determined to be set first. If the current location is set, the current location is set, and if the current location is not set, the destination is set.

The destination setting routine is performed as shown in FIG. First, it is determined whether the destination has been set, and if not, the current location selection routine is called.
In this routine, the destination is set, and if it has been completed, a map centered on the destination is displayed.Next, the distance from the current location to the destination is calculated and the distance is displayed. Thereafter, the operation of the cancel key 56 is determined, and when the cancel key 56 is operated, the process returns to the first step, and when the cancel key 56 is not operated, a map centered on the destination is displayed.

Eight types of map scales are available, and when the reduction key 57 is operated when setting the scale, the image on the display device 29 is rewritten to a map with a scale one step lower, and the range of the scale before rewriting is changed. A cursor indicating the
Only 1 (black)~゜, 8 are displayed when the reduction key 57 is further operated.

Since the size of the cursor becomes equal to the screen size of the furniture display device 29, the cursor disappears from the screen, but when the reduction key 57 is further operated, the cursor is displayed on the screen again.

When the enlargement key 58 is operated, a cursor indicating the range of one scale higher is displayed. When the enlargement key 58 is further operated, the cursor becomes smaller one by one. For example, as shown in FIG. 23, the cursor shown on the outside changes in size to the size shown on the inside, and as the cursor is further operated, it becomes even smaller.

For example, if the scroll key 59 is operated in such a state.

The cursor position remains in the center of the screen and does not change, but
The map moves up and down and left and right. When the desired position is found in this way and the set key 55 is operated with the cursor displayed, the range displayed by the cursor is displayed on the screen at that scale, and at this time the cursor changes to a cross mark. (Figure 24). Furthermore, operate the scroll key 59 to move the map up and down, left and right, make the desired position correspond to the center cursor, and press the set key 55.
If you operate , your current location or destination will be set to that location.

The reduction key 57, enlargement key 58 and set key 5.
If the changes in the screen due to each operation in 5 are displayed together, the second
The result will be as shown in Figure 5. In the figure, blocks indicated by upward arrows represent enlargement operations, blocks indicated by downward arrows represent reduction operations, and blocks indicated by the letters SET represent set operations. When the screen changes horizontally in the diagram, it means that the scale of the map does not change. million, 1/200,000, 1/10,000, 1
The scales are 150,000, 1/25,000, and 1/12,500.

It is also possible to move the cursor instead of the map when the scroll key 59 is operated. However, if you do this, for example, when moving the cursor while searching for a predetermined destination, if you find that the destination is outside the displayed map, you will need to perform a separate operation to redraw the displayed map. This results in interruptions in operation and poor operability. Therefore, as in the example, the cursor is fixed at approximately the center of the screen and the map is moved.
Preferably, the destination can be searched simply by continuously operating the scroll key 59.

In this way, two types of cursors are used to perform enlargement, reduction, and scrolling, which not only makes one display easier to see, but also improves operability. When it's time to expand again.

After the target scale is set, when the set key 55 is operated, a drawing operation to the memory (which takes time), which will be described later, is started, so the operation can be performed smoothly.

The 0 display routine, which will be described next, is carried out according to the flowchart shown in FIG. In this routine, first the direction sensor 7, the speed sensor 8
The current location of the vehicle is calculated by the processor 10 from such information. Alternatively, when latitude and longitude information is input from the GPS device 9, the current location can be specified from this information. Calculation of the current location is performed at regular intervals.

The data is constantly updated. Next, it is determined whether or not there is a map centered on the current location in the storage memory 5. If not, the data is stored from the CD-ROM 1 on the memory 5. loaded.

When a map centered on the current location is stored in memory 5 2
Next, it is determined whether the map centered on the current location is within the range of the map drawn in memory 16 or 17, and if it is not within the range, the back side of memory 16 or 17 (memory 20
Drawing (rewriting) is performed by the controller 15 in the memory of the memory (to which data is not supplied).

If a map centered on the current location is written in the memory 16, 17, then it is determined whether or not a map of another scale is loaded in the memory 5, and if it is not loaded, the map is transferred from the CD-ROMI to the memory 5. loaded on top.

When a map of another scale is written on the memory 5, it is first superimposed on the map on the front side of the memory 16 or 17 (the one whose data is being transferred to the memory 20), and the processor 1o
A military mark is written by the processor 6 in accordance with the current location calculated by the processor 6, and this data is further transferred from the memory on the front side to the memory 20. This own vehicle mark is a mark that allows the direction of travel to be recognized, for example, as shown in the center of Figure 21 (the figure shows the vehicle traveling northward (upwards)). In this way, memory 2
The map and army mark written in 0 are further stored in memory 21.
The image transferred to and stored in the memory 21 is displayed on the display device 2.
9 will be displayed. After further processing of routines such as enlargement and reduction, the process moves to the next step.

By a similar operation, the direction from the current location to the apparent location is displayed as shown by the arrow in the upper right corner of FIG.

The step of loading map data from the CD-ROM 1 (indicated by A in the figure) in the above display routine is shown in more detail in FIG. That is, the first
As shown in FIG. 6, first, a predetermined area (indicated by a broken line in the figure) is set around the current location P, and the file number of the map within that area is set.

As shown in FIG. 16, a predetermined range (soo.

The map data of Hx8000H (H is a hexadecimal unit) is equally divided into four by two straight lines, a horizontal line and a line perpendicular to it, and the lower left area is 0. The lower right area corresponds to number 1, the upper left area corresponds to number 2, and the upper right area corresponds to number 3. Each of the four areas is then further divided into four smaller areas and numbered in the same way, with the first number being represented by the first digit, the next number being represented by the second digit, and so on. are divided and numbered 1 (file number). Therefore, the data of the area centered on point P in Fig. 16 is O (1/1.6 million scale map).

03 (1/800,000 scale map), 030.031.
032.033 (map with a scale of 1/400,000), etc., exists in the map represented by each file number. However, the price for CD-ROMI is 1/800,000.

Only maps of 1/20,000, 1,150,000, 1/1,250,000 scales are available, 1/1,600,000, 1/400,000, and 1/10.
Maps at scales of 10,000 and 1/25,000.

It is expressed by thinning out and drawing the data of the map at the above-mentioned scale. The distance between two points on this map is calculated as a rectangular coordinate system using predetermined units of latitude and longitude near the center (4000H, 4000H) as reference degrees.

In this way, map data including the current location at each scale (four scales) to which the file numbers as described above are assigned is read from the CD-ROMI and written into the memory 5. Further, as shown in FIG. 18, a predetermined range centered around the current location (range indicated by the center line of Wi) is clipped on the memory 5, and this clipped range is written to the back side of the memory 16 or 17. It will be done.

Since the current location moves as the vehicle travels, the steps of calculating the current location and displaying the own army mark are interrupted at predetermined intervals in the flow of steps 2-9.

The details of the step of rewriting data in the memories 16 and 17 (indicated by reference numeral B in the figure) shown in FIG. 6 are as shown in FIG. 8, for example. In other words, the memory 16 and 17 are on the back side when drawing is done by the controller 15, and the memory 2 is on the back side when drawing is completed.
The side that is transferring data to 0 is considered to be the front side, and the controller 15 always draws in the memory of the back side, and when the drawing is completed, the front side and the back side are reversed. For example, the first
As shown in FIG. 8, only a portion of the image drawn on the front side of the memory 16, 17 within a predetermined range is transferred to the memory 20 and further to the memory 21, and displayed on the display device 29. Therefore, in this flow as well, as the vehicle travels, the steps of calculating the current location and displaying the own army mark are interrupted at predetermined intervals, but once the memory
6.17, it is not necessary to rewrite the data very often. 1 display device 29 as the vehicle travels
When the range displayed on the screen exceeds the range written in the memory on the front side, the data needs to be rewritten.

However, rewriting the data requires some time. Therefore, as shown in FIG. 17, a predetermined distance D (distance on the memory -) defines an outer range (indicated by a broken line in the figure), and when this outer range exceeds the range of the map drawn in the front memory.

A map centered on the current location at that time is read from the memory 5 and drawn in the memory on the back side. Further, this distance is changed depending on the scale of the map. Therefore, the smaller the scale (the more the map is enlarged), the faster the display position of your army's mark will move on the map, but writing to the memory on the back side will be done faster, so only a portion of the map will be visible on the screen. is prevented from being displayed as being missing.

Furthermore, the step of transferring the map drawn in the memories 16 and 17 to the memory 20 in FIG. 6 (indicated by C in the figure) is shown in more detail in FIG. 9. That is, first, in the front side memory of the memories 16 and 17, the data of the range (16×16 dots) in which the own army mark at the center of the range to be transferred to the memory 20 (FIG. 18) is displayed is temporarily saved to the memory 5. And there processor 6
In response to the command, the controller 15 draws the own army mark. At this time, the own army mark is displayed in a direction corresponding to the traveling direction of the vehicle detected by the calculation of the processor 10.

The map centered on the vehicle mark drawn in the front side memory in this way is transferred to the memory 20. The range to be transferred is specified by the offset register 22 (and therefore the address counter 23). That is, under the control of the processor 6, the offset register 22 stores predetermined coordinate values that change in accordance with the current location. This value is the 18th
As shown in the figure, the position (X) of the dot where the controller 15 starts transferring on one horizontal scanning line, and the position (Y) of the horizontal scanning line where the controller 15 starts transferring on one field.
). Therefore, for example, focusing on one horizontal scanning line, as shown in FIG. 19, dot counting is started at the timing of the horizontal synchronizing signal, and when a predetermined offset value X is counted, a predetermined number of dots are counted from the next dot. The video signal in the represented range is transferred to the memory 2o.

Also, if we focus on the field, as shown in Figure 20,
When the transfer command is output from the processor 6 to the controller 15, counting of horizontal synchronization signals is started at the timing of the vertical synchronization signal of the controller 15 that arrives thereafter,
After counting a predetermined offset value Y, data in a range of a predetermined number of scanning lines from the primary scanning line is transferred to the memory 2o.

Once the data is transferred to the memory 20, the data is further transferred to the memory 21 at the timing of the vertical synchronization signal of the display device 29 that arrives after that, taking the time of one field of the display device 29.

The data written in the memory 21 is read out and displayed on the display device! 29 is displayed. The display device 29 is driven by a synchronizing signal such as the NTSC system so that it can also display images of normal television broadcasting. Therefore, the memory 21 that outputs data to the display device 29 is also driven by a clock having the same frequency as the synchronization signal of the NTSC system or the like.

On the other hand, the synchronization signal of the controller 15 controlled by the processor 6 as a computer (for example, the frequency of the horizontal synchronization signal is 24.83kHz) is generally the synchronization signal of the NTSC system (for example, the frequency of the horizontal synchronization signal of the NTSC system is 15.83kHz). 75kHz), it is not possible to drive the display device 29 (memory 21) with the synchronization signal of the controller 15, so the memory 21 and the memory 16.
A memory 2o is arranged as a buffer between 7 and 7, and the writing clock is the same as that of the memories 16 and 17, and the reading clock is the same as that of the memory 21.

Further, when data is transferred to the memory 2o, the color signals of the three primary colors, each represented by a 3-bit signal, are converted into a 15-bit color signal by the color palette register 19. This 15-bit color signal is specified by the processor 6. Therefore, the 8 types of low gradation colors represented by 3 bits are converted to any of the 32 types of high gradation colors represented by 5 bits each of R2O and B, and by appropriately mixing the 3 primary colors, 32768 colors are converted. It becomes possible to specify any eight types of colors from among the colors. Address counter 25 outputs predetermined address signals to color palette register 19 and memory 20, 21 in order to specify the position of each dot undergoing color conversion. The digital data of the map and military marks written in the memory 21 are converted into analog signals by D/A conversion circuits 26, 27, and 28, and displayed on the display device 29. As described above, since the maps do not overlap in the area where the own army mark is displayed, it is possible to prevent the display of the own army mark from becoming difficult to see on the screen (FIG. 21).

When the transfer from the front side memory to the memory 20 is completed,
The map data saved in the memory 5 is returned to the front side memory again. In this way, the operation of saving and restoring the map data in the area where the own vehicle mark is displayed is repeated as the vehicle moves, so the amount of calculations and the amount of memory used can be reduced. -ROM
The number of accesses to I is reduced, allowing smooth display.

The map data written to the memory 5 has a scale of 1/80.
1/200,000, 1/200,000 and 1,150,000 are considered 8ooxsoo dots, and these are 1/1,600,000 and 1/4, respectively.
When drawn in the memory 16.17 at a scale of 00,000 and 1/100,000, it is 400×400 dots. Also, map data with a scale of 171°250,000 is 1600X160
0 dot, and when this is scaled to 1/2,50,000 and drawn in memory 16.17, it is 80o x 80.
It is considered as 0 dot. Smallest scale (enlarged) 1/1
．． This increases the number of dots on the 250,000 map compared to other large scale (reduced) maps.

Of course, the number of dots can be the same, but the current location will move faster on a smaller scale map. Therefore, as in the example, if the number of dots is increased in the case of a small scale than in the case of a large scale, the C.
The frequency of access to D-ROMI can be reduced accordingly.

On the other hand, the drawing memory 16.17 has 640×400 dots (high resolution or large capacity), the display memory 20.21 has 256×256 dots (low resolution or small capacity), and the screen of the display device 29 has, for example, 256×216 dots.

The processor 6 can directly write, for example, a photographic image of an intersection, etc. recorded on the CD-ROMI into the memory 20. In this case as well, since the image data being displayed on the display device 29 is output from the memory 21, the displayed image is not affected by the writing operation. In this way, the display device 29 can alternatively display either an image drawn in the memory 16, 17 by the controller 15 under the control of the processor 6, or an image drawn directly in the memory 20 by the processor 6. It has become.

Next, an example of recording map data will be described. As is well known, a map is a flat representation of the state of the earth on a spherical surface. There are various ways to express it, but the maps published by the Geospatial Information Authority of Japan use the Transverse Mercator projection for relatively small scale maps (relatively enlarged maps) of 1/2 million or less. Also, relatively large scale maps exceeding 1:200,000 (relatively reduced maps) are mapped using the conic projection. Therefore, for example, as shown in Figure 10, if multiple maps of a predetermined range are arranged on a plane so that the left and right boundaries are not far apart, the distance between two points can be accurately expressed. , the north-south direction and the east-west direction are not perpendicular to each other, and if each map is digitized as is, it is necessary to display the north-south direction and the east-west direction on the screen of the display device 29 with the north-south direction and the east-west direction tilted with respect to the vertical or horizontal direction. This results in a large discrepancy between the user's sensation and the operability. Moreover, if this is done, the calculations for specifying the current location on the map become complicated, increasing the burden on the processor 10. Therefore, in the present invention, as shown in FIG.
Multiple maps drawn for each predetermined area using a projection method such as the Transverse Mercator projection or conic projection are drawn in the east-west direction on a predetermined plane so that the reference latitude lines for each area are located on the same horizontal line. At the same time, the reference meridians on the reference latitude lines are located on the same straight line perpendicular to the horizontal line, so that they are located next to each other in the north-south direction, and the positions on the map are specified by rectangular coordinates on that plane. There is. FIG. 11(a) is an example where the lower left point of each map in a predetermined range is set as the reference point B of the reference latitude and longitude line,
FIG. 6(b) is an example in which the point 0 of the middle shaft is set as the reference point B.

However, in any case, when calculating the distance between two points on the map, the length per latitude (meridian) in units (for example, lokm) at point 0 on the map is used as a reference.

Then, as shown in FIG. 12(b), discontinuous portions that occur in left and right adjacent maps are corrected so that the portions are located on a vertical straight line. As a result, for example, point A on the upper right (northeast) of a 1/200,000 scale map and point A2 on the upper left (northwest) that corresponds to point ○ on the map of the area east of it.
is replaced by point A. If we convert the earth coordinates to rectangular coordinates (Cxty") in this way, for example, 1/20
The maximum error that occurs in 10,000 maps is ±70m,
As shown in FIG. 12(a), the error is locally concentrated in a predetermined range in the north-south direction (the shaded area in the figure).

As a result, the distance error in this area increases, but
The overall east-west direction is horizontal.

The north and south directions can be displayed vertically, which matches the user's senses, improving operability and making it easier to calculate the current location.

Data expressed on a map includes line segments,
Symbols and place names are provided. The a minute data is the first
It is configured as shown in Figure 3.

In other words, line segment data includes major national roads, local roads, other roads,
For example, the 6 package packages are categorized by 8 types of lines (represented by 8 bits of data) such as coastlines and railways, and attributes (represented by 7 bits) such as tunnels and streetcars. They are prepared for each type of line to be displayed, such as a red line, a predetermined number of packages form one set, and end data (d d d d h) is arranged at the end of one set.

Further, in each package, attribute and line type data are arranged as a header at the beginning, followed by the total number of strokes in the package, and then each stroke data.

One stroke represents one continuous line segment. Each stroke data is expressed by the number of cylinders of the unit line segment and the coordinates of the start and end points in units of 10 m (the same applies below). 61 strokes The end point of a line segment that is one unit of the unit is the start point of the next unit line segment, so the coordinate data of the starting point of each unit line segment and the end point of the last unit line segment is 1 The data consists of two strokes.

Two types of line types are available for river or coastline data. In other words, as shown in Fig. 22, rivers and coastlines themselves are represented by solid lines, and by placing a broken line at a predetermined distance away from the solid line toward the river or sea, it can be shown that the side of the broken line is the river or sea side. is expressed. Since such display does not take much time, it is performed when it is necessary to increase the drawing speed (for example, when the traveling speed of the vehicle is fast compared to the scale of the map). On the other hand, if there is no need to significantly increase the drawing speed, the dots are colored sequentially horizontally from point Z using a predetermined point 2 on the dashed line as a reference until the scanning line intersects with the solid line representing the coastline. . Although it takes some time to color rivers, oceans, etc. in this way, it takes less time than the conventional method of directionalizing solid lines representing rivers and coastlines and coloring one side of them. Can be colored. Also, the calculations for this purpose become easier.

Roads are expressed in different colors depending on the scale even if they are the same road, and at a given scale, a predetermined color is used.
Only roads (roads included in a predetermined package) are displayed.

Symbols representing ski resorts, hotels, mountains, gas stations, parking lots, etc. are available. The symbol data is structured as shown in FIG. That is, symbols are also packaged into predetermined symbols, and end marks (e e e
e h) are arranged. The number of symbol packages is limited to 256 or less. Each package contains a 7-bit serial number of the symbol (for example, a serial number among symbols representing a mountain) and an 8-bit symbol pattern corresponding to each symbol (for example, what number is the mountain symbol? Each symbol corresponds to one number) as the header, followed by the number of symbols (always 1 in this example) and the coordinates where the symbol will be displayed. is located.

FIGS. 21 and 22 show examples in which a mountain symbol is displayed. Mountains are generally displayed as contour lines on maps. However, if it is represented as contour lines, not only does the amount of map data increase, but also the display device 29, which is used as a vehicle navigation device, cannot be made very large in screen size, making it look despised. Therefore, it is preferable to display the mountain as a relatively small symbol as in the embodiment.

The place name data is structured as shown in FIG. In other words, as in the case described above, an end mark (f f f
f h) are arranged. A place name level consisting of 8 bits is arranged as a header of each place name package. Eight types of place name levels are prepared, and only place names of a predetermined place name level are displayed on the display device 29 at a predetermined scale. Next to the place name level, the number of place name cylinders contained in the package and each place name data are arranged. For each place name, the coordinates where the place name should be displayed, the number of characters (up to 6), and a Kanji code are arranged.

〔effect〕

As described above, the present invention provides a vehicle navigation system that includes:
A current location detection means for detecting the current location of the vehicle; and a storage medium that stores map information of a first scale.

a first memory that stores map information of a first scale 7 including the current location read from the storage medium; a controller that reads at least part of the map information from the first memory and draws it on a second memory; a display device for displaying the map information stored in the second memory, and the controller transfers the map information in the first memory as it is to the second memory for a predetermined range, and displays the map information on the first scale. At the same time, only part of the ground information within a predetermined range is transferred to the second memory, and map information at a second scale different from the first scale is drawn. Therefore, it is possible to use a small-capacity storage medium because it is possible to store fewer scale maps in advance in the storage medium. Therefore, the device can be downsized and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the vehicle navigation system of the present invention, FIG. 2 is a plan view of its display device and keyboard, and FIGS. 3 to 9 are its flowcharts. Figures 10 to 12 are explanatory diagrams explaining the conversion of the earth coordinates to orthogonal coordinates, Figure 13 is an explanatory diagram of the line segment data, Figure 14 is an explanatory diagram of the symbol data, and Figure 15 is an explanatory diagram of the data of the line segment.
The figure is an explanatory diagram of the place name data. FIG. 16 is an explanatory diagram explaining how the map is divided, FIG. 17 is a schematic explanatory diagram of the memory, FIG. 18 is an explanatory diagram schematically explaining data reading and writing, and FIG.
The figure is the waveform diagram, Figure 20 is the timing chart,
Figures 21 to 24 are plan views of the display screen, Figure 25
The figure is an explanatory diagram of enlarged and reduced screens. 1...CD-ROM 2.13...Interface 5.16.17.20.21...Memory 6...Information processor 7...Direction sensor 8.
...Speed sensor 9...GPS device 10...Navigation processor 11...ROM 12...Keyboard 15...
・Graphic display controller 18...Parallel/serial conversion circuit 19...Color palette register 22...Offset register 23.25...Address counter 24...Synchronization signal generation circuit 26.27.28...D /A conversion circuit 29...Display device or higher

Claims (1)

[Scope of Claims] Current location detection means for detecting the current location of a vehicle; a storage medium for storing map information of a first scale; and a map information of the first scale including the current location read from the storage medium. a first memory that stores map information; a controller that reads at least a portion of the map information from the first memory and draws it on a second memory; and displays the map information stored in the second memory. a display device, the controller transfers the map information in the first memory as it is to the second memory for a predetermined range, draws the map information at the first scale, and displays the map information in the first scale. A vehicle characterized in that only part of the map information within a predetermined range is transferred to the second memory, and the map information is drawn at a second scale different from the first scale. navigation device.