JPH0467126B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an in-vehicle navigator that displays the current position of a vehicle on a road map. [Prior art] Conventionally, this type of device was disclosed in Japanese Patent Application Laid-Open No. 52-141662.
There is a "traffic display device" which reads the map recorded on a recording medium such as micro film with an optical reader using a vidicon camera etc., displays the road map of a specific area on the display device, and displays it. The road map can be enlarged or reduced by zooming. [Problems to be Solved by the Invention] However, since the enlargement/reduction (scale change) of the road map by the above device is performed simply within the range of the displayed road map, the amount of information displayed remains unchanged. It simply makes the display easier to read. The present invention has been made in view of the above problems, and an object of the present invention is to provide an in-vehicle navigator that can also change the amount of information when changing the scale of road display in a specific area. [Means for Achieving the Object] In order to achieve the above object, the present invention, as shown in FIG. and display means for displaying a road map based on the map data from the storage means and additionally displaying the current position detected by the current position detection means on the road map. In the navigator for use, the storage means stores first map data for displaying a specific road map and first scale data indicating a scale of the road map, and also stores first map data for displaying a specific road map and first scale data indicating a scale of the road map. It stores second map data of a road map with a different scale and second scale data indicating the scale of the road map, and the road map has a different scale with respect to the road map displayed on the display means. a changing means for generating a change instruction for displaying a specific road map; a changing means for reading first map data from the storage means to display a specific road map on the display means; map display control means for reading out second map data from the means and switchingly displaying road maps of different scales on the display means; The present invention is characterized by comprising a current position correcting means for correcting and displaying the current position displayed on the display means based on the second scale data and the first scale data. [Operation] In the above configuration, map data for displaying a specific road map and map data with different scales for the specific road map are stored in the storage means, and the changing means issues an instruction to change the scale of the road map. When this occurs, map data of a road map having a different scale from the currently displayed road map is read from the storage means and the road map is displayed on the display means. Furthermore, when displaying the road map with a different scale, the current position displayed on the display means is corrected based on at least the second scale data stored in the storage means and the first scale data. Is displayed. [Effects of the Invention] As shown in the above configuration and operation, in the present invention, map data with different scales are individually stored and used to display road maps with different scales. When changing the scale of road display in a specific area, it is possible to display a map with a different amount of information, and when changing to a road map display with a different scale, the current position display is corrected to the corresponding position on the new road map. It has an excellent effect in that it can be carried out as follows. [Example] The present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram showing one embodiment. In Fig. 1, reference numeral 1 denotes a direction detection device as direction detection means, which includes a direction sensor that detects the X and Y components of the earth's magnetism according to the direction in which the vehicle is traveling, and converts the signal from this direction sensor into a digital signal. It is equipped with an A/D converter and generates digital signals of X and Y components depending on the traveling direction of the vehicle. Reference numeral 2 denotes a distance sensor as a distance detecting means, which generates a distance pulse every unit traveling distance of the vehicle (for example, about 39.2 cm). Reference numeral 3 denotes a reading device which reads map data of a specific district among them by setting a cassette tape 3a serving as a storage means that stores map data of a plurality of districts (including absolute coordinate data of the upper right point of each map). It is something to explore and read. 4 is a microcomputer that executes software digital arithmetic processing according to a predetermined control program, and includes a CPU 4a, ROM 4, and RAM 4.
c. It is equipped with an I/O circuit section 4d, and is activated by receiving a stabilized voltage from a stabilized power supply circuit (not shown) that generates a stabilized voltage of 5 V by receiving power from an on-board battery. , receives digital signals of X and Y components from the direction detecting device 1, distance pulses from the distance sensor 2, read signals from the reading device 3, etc., performs arithmetic processing, and obtains map and driving route information of a specific area, etc. It generates display signals for display. Note that the RAM 4c is constantly backed up with power from the on-board battery. 5 is a cathode ray tube (CRT) controller,
In response to a display signal from the microcomputer 4, map data, driving route information, and character data of a specific area are individually stored, and the stored map data, driving route information, or character data is displayed on a CRT. It generates video signals and synchronization signals for Reference numeral 6 denotes a CRT display device as a display means, which displays a map of a specific area, a driving route, or a character on the CRT using the video signal and synchronization signal from the CRT controller 5.
It is to be displayed. 7 is the touch panel section,
It is mounted on the display surface of the CRT display device 6, and generates a serial signal in response to a touch operation on a specific touch area among the 12 divided touch areas provided on the touch panel. Reference numeral 8 denotes a map changeover switch section as a changing means, which includes two switches (enlargement switch, reduction switch) for switching the map displayed on the CRT display device 6 to another map of a different scale.
It is equipped with the following. The reading device 3, microcomputer 4, and CRT controller 5 constitute a control means. Next, the CRT controller 5 shown in FIG.
The detailed electrical wiring diagram will be explained. 11 is
Oscillation circuit that generates a 12096MHz oscillation signal, 12
divides the oscillation signal from oscillation circuit 11 to 6048MHz
13 is a dot counter that generates a dot timing clock of A display controller 14 generates a signal, a refresh memory address signal, and a raster address signal, and a display controller 14 generates a hold signal to hold the microcomputer 4 during the display period based on the horizontal and vertical synchronization signals from the display controller 13. This is a hold signal generation circuit that is generated at the hold (HOLD) terminal. 15 is a multiplexer which switches the address signal from the microcomputer 4, the refresh memory address signal from the display controller 13, and the raster address signal in response to a hold acknowledge (HOLDA) signal from the microcomputer 4; 16, 17, and 18 are A bus driver 19 has a tri-state that switches the direction of data between the microcomputer 4 and the display memory, and a bus driver 19 stores display data such as ASCII codes from the microcomputer 4 and receives a refresh memory address signal from the display controller 13. A character memory 20 receives the data and outputs the contents as an address, and a character generator 20 outputs a display pattern based on a display address from the character memory 19 and a raster address signal from the display controller 13. 21 is a first graphic memory that stores map data from the microcomputer 4; 22 is a second graphic memory that stores travel route information (travel trajectory data, current position data) from the microcomputer 4; 23; 24 and 25 are parallel to serial (P to S) converters that convert parallel signals from the character generator 20 and the first and second graphic memories 21 and 22 into serial data using the dot timing clock from the dot counter 12.
A converter 26 switches reception of signals from the P→S converter 23 and P→S converters 24 and 25 in order to select between graphic and character screens in response to a screen switching signal from the microcomputer 4. A video controller 27 generates a video signal based on a display timing signal, and 27 is an exclusive OR circuit that generates a synchronization signal based on horizontal and vertical synchronization signals from the display controller 13. Note that the character memory 19, the first
The second graphic memories 21 and 22 are constantly backed up with power from an on-vehicle battery. That is, this CRT controller 5 stores character data in the character memory 19 based on the data sent from the microcomputer 4.
Then, the map data is stored in the first graphic memory 21.
The display data of the travel trajectory and current position is constantly stored in the second graphic memory 22, and the graphic screen (displaying the map, travel trajectory, and current position) and the character are displayed by a double-sided switching signal from the microcomputer 4. The CRT display device 6 generates a video signal and a synchronization signal for selecting a screen (displaying designated characters, etc. to designate a district) and displaying a screen corresponding to the selection on the CRT. The touch panel section 7 has 12 touch areas 31 to 42, as shown in FIG. configured,
When a specific touch area is pressed, the touch area is detected by the contact of the transparent conductive film of the matrix due to the bending of the glass, and a serial signal (start signal) corresponding to the touch area detected by a touch signal generation circuit (not shown) is detected. and touch information signals). Note that this touch signal generation circuit generates the touch information at that time in the form of a serial signal every 40 msec. Furthermore, Fig. 4a shows a data area corresponding to one district on the cassette tape 3a, A is the header part, and as shown in Fig. 4b, the map number A(1) and the map number are as follows. Absolute coordinates of the upper right point (coordinates relative to the North Pole) data A (2), map to CPT
Distance per pixel when displayed, that is, scale A
(3), a scale map number A (4) with a different scale for the area that covers the map, and an enlarged map number A (5) with a different scale that displays the specific area of the map in detail. . Of these, the data for enlarged map number A(5) is in a format that can be selected by positioning the cursor on the CRT screen. (For example, divide the screen into four parts and display the area where the cursor is located on a twice-enlarged map.)
B is a map data section storing map data of the area, and X is a blank section. Therefore, by reading parts A and B with the reading device 3, the microcomputer 4 is provided with map data of a specific area,
Absolute coordinates, scales, and map numbers with different scales of the map can be given. The operation in the above configuration will be explained with reference to the display explanatory diagram in FIG. 5 and the calculation flowcharts shown in FIGS. 6 to 9. FIG. 6 is a calculation flowchart showing the overall calculation processing of the main routine of the microcomputer 4, FIG. 7 is a calculation flowchart showing the calculation processing of the interrupt calculation routine based on the distance pulse from the distance sensor 2, and FIG. FIG. 6 is a calculation flowchart showing detailed calculation processing of the mode calculation routine, and FIG. 9 is a calculation flowchart showing detailed calculation processing of the current position calculation routine in FIG. Now, in a vehicle equipped with components 1 to 7 shown in FIG. 1, when a key switch is turned on at the start of operation, each part of the electrical system is activated by receiving power from the vehicle battery. The microcomputer 4 then enters the operating state by receiving the stabilized voltage of 5V from the stabilized power supply circuit, starts its calculation station from the start step 100 in FIG. 6, and proceeds to the initial setting routine 200. The registers and counters in the microcomputer 4,
Sets latches, etc. to the initial state necessary to start arithmetic processing. After this initial setting, a mode calculation routine 300 and a current position calculation routine 400 are executed.
The arithmetic processing is repeatedly executed at a period of about several tens of milliseconds. That is, in this mode calculation routine 300, one of the map mode and character mode is selected, and the content corresponding to that mode is selected.
A CRT display is displayed, and when in the map mode, it is possible to move a cursor indicating the current position, and furthermore, it is possible to switch maps by instructions from the map changeover switch section 8, and when in the character mode, it is possible to specify a specific map. The arithmetic processing is executed and the process proceeds to the current position calculation routine 400. This current position calculation routine 400 executes calculation processing to change the contents of the current position data and travel trajectory data X and Y components in the second graphic memory 22 in the CRT controller 5 with a travel change of 50 m. , the process returns to the mode calculation routine 300. Thereafter, the main routine arithmetic processing from the mode arithmetic routine 300 to the current position arithmetic routine 400 is repeatedly executed at a cycle of approximately several tens of milliseconds. When a distance pulse from the distance sensor 2 is applied to the interrupt (INT) terminal of the microcomputer 4 in response to the repeated calculations of this main routine, the microcomputer 4 temporarily suspends the calculation processing of the main routine. The interrupt calculation process shown in FIG. 7 is executed. That is, the interrupt start step
The calculation process starts from 501, and the integration step 502
Proceed to the distance data D stored in RAM4c.
The unit distance data (corresponding to about 39.2 cm) is integrated and updated, and the process proceeds to distance determination step 503, where it is determined whether the distance data D has reached 6.25 m. At this time, if the distance data D has not reached 6.25 m, the determination will be NO and the process will proceed to return step 510, but if the distance data D has reached 6.25 m, the determination will be NO.
The answer is YES, and the process advances to direction signal input step 504.
Then, in this azimuth signal input step 504, the digital X and Y component signals from the azimuth detection position 1 are input.
Input Xa, Ya (positive directions for east and north, negative directions for west and south), proceed to step 505 to calculate average direction, and use the previous direction data Xo, Yo (direction data before traveling 6.25 m) and the current direction. Calculate the average direction data X and Y from the direction data Xa and Ya, and perform the distance component calculation step.
Proceed to 506 and calculate the distance component Dx in the X direction.

[Formula] Distance component Dy in the Y direction

Find as [Formula] (

[Formula] is a counterclockwise rotation based on the east direction. cos θ for angle θ,

[Formula] corresponds to sinθ), proceed to storage step 507 and store the current direction data.
Remember Xa, Ya as Xo, Yo for next time,
The program proceeds to distance data memory set step 508 to reset the distance data D to 0, proceeds to distance flag set step 509 to set the distance flag, and proceeds to return step 510 to return to the previously interrupted main routine. That is, in this interrupt calculation routine, the distance data D is cumulatively updated every time a unit distance is traveled, and when the distance data D reaches 6.25 m, the distance components in the X and Y directions that reach this 6.25 m are updated.
Calculates Dx and Dy and executes arithmetic processing to set the distance flag. Next, detailed calculation processing of the mode calculation routine 300 in the main routine will be explained. In this mode calculation routine 300, the calculation process starts from the map changeover switch determination step 301 in FIG. , the program proceeds to map mode determination step 302 and determines whether the contents of the mode area in RAM 4c are map mode.
When in map mode, the judgment becomes YES,
Proceeding to map number search step 303, the map number to be switched is found based on the header part data and cursor position data for the currently displayed map data stored in the RAM 4c, and the process proceeds to travel route data conversion step 304, where the CRT controller 5
The travel route data in the second graphic memory 22 is converted. In this case, first, control the reading device 3 to search for the cassette tape position corresponding to the map number obtained in the previous step, read this header section, and use the absolute coordinates and scale of the header section and the absolute coordinates and scale of the previous map. A coordinate conversion value is calculated, and the travel locus and current position data in the second graphic memory 22 are converted so as to slide according to the calculated values. The program then proceeds to map data reading and outputting step 305, where map data from the cassette tape 3a is input via the reading device 3 and the map data is transferred to the first graphic memory 2.
1 of this mode calculation routine 300.
Finish the calculation process. In other words, if you want to switch from the map screen to a reduced map that covers the area, press the reduction switch, and if you want to switch to an enlarged map of a part of that area, move the cursor to the position you want to enlarge and press the enlargement switch. This allows the map to be displayed on the CRT display device 6 to be automatically switched. On the other hand, the map changeover switch determination step 301
and the determination in map mode determination step 302 is NO.
In this case, the process advances to touch data input step 306, where the touch data from the touch panel section 7 is input.
Store in RAM4c. Then, the process proceeds to map mode determination step 307 to determine whether the contents of the mode area in the RAM 4c are map mode.
It is determined whether the touch data stored in 4c is data indicating a mode change (data when touch area 34 in FIG. 3 is pressed). At this time, if the touch data is data indicating a mode change, the determination becomes YES, and the process proceeds to character mode setting step 309, sets the contents of the mode area to character mode, and proceeds to character switching signal output step 310. Then, a character switching signal for displaying the character screen on the CRT display device 6 is generated to the video controller 26 in the CRT controller 5, and one calculation process of this mode calculation routine 300 is completed. On the other hand, when the touch data is not data indicating a mode change, that is, data when a touch area other than 34 in FIG. 3 is pressed, or data when no touch area is pressed (for example, data called FE). Sometimes, the determination in the mode change determination step 308 becomes NO, and the process proceeds to the cursor movement determination step 311. In this cursor movement determination step 311, it is determined whether the touch data is data when any of the touch areas 32, 33, 35, 38, 40, and 41 is pressed (cursor movement data), If the touch data is not cursor movement data, the judgment becomes NO and one calculation process of this mode calculation routine 300 is completed, but if the touch data is cursor movement data, the judgment becomes YES and the cursor moves. Proceed to calculation step 312. In this cursor movement calculation step 312, in accordance with the touch data, the cursor at the current position displayed on the CRT display device 6 is moved a predetermined distance northward, indicating that the touch data is data for pressing the touch area 32 or 33. Similarly, if the touch data corresponds to pressing the touch area 35, move the cursor westward, and if the touch data corresponds to the press of the touch area 40 or 41. The second graphic memory 22 is configured to move the cursor a predetermined distance southward if the data corresponds to the press of the touch area, and to move the cursor eastward by a predetermined distance if the data corresponds to the press of the touch area 38.
Then, the mode calculation routine 300 completes one calculation process. On the other hand, if the determination in the map mode determination step 307 is NO, the process advances to a mode change determination step 313.
It is determined whether or not the mode is to be changed using the same calculation process as in the mode change determination step 308. At this time,
If the determination is YES when changing the mode, the process proceeds to a map mode setting step 314 to set the contents of the mode area in the RAM 4c to the map mode, and proceeds to the driving route data conversion step 315 to change the second graph in the CRT controller 5. ITSUKU MEMORY 22
Convert driving route data. In this case, first, the reading device 3 is controlled to search for a specified district using its map number, and the absolute coordinates and scale (stored in header A shown in Figure 4) on the map of the searched district and the previous district are searched. A coordinate conversion value is calculated using the absolute coordinates and scale data on the map, and the travel trajectory and current position data in the second graphic memory 22 are converted so as to slide in accordance with the calculated values. Then, the map data reading output step
Proceeding to step 316, the map data of the cassette tape 3a is inputted via the reading device 3, and the map data is outputted to the first graphic memory 21.
Proceeding to map switching signal output step 317, a map switching signal for displaying the map graphic screen on the CRT display device 6 is generated to the video controller 26, and one calculation process of this mode calculation routine 300 is completed. That is, when switching from the character screen to the graphic screen of a map different from the previous one, the above calculation process is executed, the current map data is stored in the first graphic memory 21, and the driving trajectory is added to the current location corresponding to this map. and converting the contents in the second graphics memory 22 to modify the cursor indicating the current location. As a result, even if the map displayed on the CRT display device 6 is changed, the travel trajectory and current location can be displayed in the area corresponding to the map. On the other hand, if the determination in the mode change determination step 313 is
If NO, proceed to character calculation step 318.
When the character calculation step 318 is reached, the character mode has been set and a character switching signal has been issued to the video controller 26, so the CRT display device 6 is in a character mode as shown in FIG. The screen is being imaged. The number 02-4 shown in the center of this character screen
-68 is a number that designates a region, region, or district, and each number is updated by adding 1 by increment switch 51, subtracting 1 by 1 by decrement switch 52, and is set and reset by set switch 53. The character calculation step is reset by switch 54.
Arithmetic processing is performed at 318. Furthermore, this region, region,
District numerical data, i.e. map number, is stored in RAM
4c. Further, the switches 51, 52, 53, and 54 mentioned above correspond to the touch areas 39, 40, 41, and 42 in FIG. 3, respectively. That is, in the mode calculation routine 300 shown in FIG. 8, the following operations are performed according to the switch signal from the map changeover switch section 8, the touch data from the touch panel section 7, and the contents of the mode area in the RAM 4c. If the map mode is in map mode and there is a map switching instruction, the map display is switched to a reduced or enlarged map. If there is a cursor movement instruction when there is no map switching instruction and the map mode is not changed, arithmetic processing for cursor movement is executed, and if there is no cursor movement instruction, the map display is continued as it is. When a mode change instruction is received while the map mode is in the map mode without a map switching instruction, the map mode is changed to the character mode and the character screen is displayed on the CRT display device 6. When there is no map switching instruction and the character mode is not changed, map changes can be accepted on the character screen as shown in FIG. If a mode change instruction is received when the mode is in character mode without a map switching instruction, the character mode is changed to map mode, the map graphic screen is displayed on the CRT display device 6, and the travel trajectory and current position are also corrected at the same time. and display it. Next, detailed calculation processing of the current position calculation routine 400 in the main routine will be explained.
In this current position calculation routine 400, the calculation process starts at distance flag determination step 401 in FIG. 9, and it is determined in the interrupt calculation process in FIG. 7 whether or not the distance flag is set. At this time, if the distance flag is not set, the determination will be NO.
One calculation process of this current position calculation routine 400 is completed, but if the distance flag is set, the determination becomes YES and the process proceeds to the X distance correction step 402. Then, in this X-distance correction step 402, a correction is calculated (DX=
DX+Dx) and similarly correct the Y distance data DY in Y distance correction step 403 (DY=DY+Dy)
Then, the process proceeds to the first X distance determination step 404, where it is determined whether the X distance data DX has reached a value of 50 m or more. At this time, if the X distance data DX is a value of 50 m or more, the determination becomes YES, and the process proceeds to the X distance subtraction step 405, where the
The value of m is subtracted, and the process proceeds to display movement step 406, where the current position data in the second graphic memory 22 is moved in the positive direction (eastward) by 50 m, and the travel trajectory data is also caused to follow this movement. . If the determination in the first X distance determination step 404 is NO, the process proceeds to a second X distance determination step 407, in which it is determined whether the X distance data X has reached a value of -50 m or less. At this time, X distance data DX
If the value is less than -50m, the determination becomes YES, and the process proceeds to the X distance heating step 408, where the value of 50m is added to the X distance data DX, and the display movement step is performed.
Proceeding to step 409, the current position data in the second graphic memory 22 is moved in the negative direction (westward) by 50 m, and the traveling locus data is also caused to follow this movement. Then, when the judgment in the second X distance judgment step 407 is NO, or in the display movement step 406,
After step 409, the routine advances to Y component display movement processing routine 410, where the same determination and calculation processes as in steps 404 to 409 are executed on the Y distance data DY calculated in Y distance correction step 403. (Y distance data
When DY reaches a value of 50 m or more in either the positive or negative direction, the current position data and traveling trajectory data in the second graphic memory 22 are moved by 50 m in the corresponding direction. ) The process then proceeds to the next distance flag reset step 411 to reset the distance flag. That is, in the current position calculation routine 400 shown in FIG. 9, the current position data and travel trajectory data in the second graphic memory 22 are converted regardless of the screen displayed on the CRT display device 6. Therefore, the current position data and travel trajectory data in the second graphic memory 22 are calculated by repeating the main routine calculations by the mode calculation routine 300 and the current position calculation routine 400, and by the interrupt calculation shown in FIG. At the same time, the screen of the CRT display device 6 is selected according to the specified mode, and if it is in the map mode, the map graphic screen (including the current position and traveling trajectory) is displayed, and the character In the mode, a character screen for map designation shown in FIG. 5 is displayed. In the embodiment described above, the operation switch is
Although the touch panel section 7 attached to the display surface of the display device 6 and the map changeover switch section 8 are provided separately, both may be composed of a matrix type push button switch of the same machine. Furthermore, the map changeover switch section 8 is omitted, and the character screen shown in FIG. 5 is configured as shown in FIG. The calculation processing from to the map data reading/output step 305 may be performed in the character calculation step 318. Further, in the above embodiment, the reduced map number and enlarged map number are stored as data in each header section A of the cassette tape 3a, but the reduced map number and enlarged map number corresponding to the cursor position are displayed at that time in advance. If there is a rule system that allows calculation from the map number of the map being displayed, it is not necessary to store the reduced map number A(4) and enlarged map number (5) on the cassette tape 3a. Furthermore, a map changeover switch section 8 is provided as a change means.
However, it is also possible to use a voice recognition device that recognizes a change instruction given by a driver's voice and generates an enlargement or reduction signal.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention;
Figure 2 is a detailed electrical wiring diagram of the CRT controller in Figure 1, Figure 3 is an explanatory diagram showing the touch area of the touch panel, Figure 4 is an explanatory diagram showing the data area of the cassette tape, and Figure 5 is the CRT display. A display explanatory diagram showing the display state of the device, Fig. 6 is a calculation flowchart showing the overall calculation processing of the main routine of the microcomputer, and Fig. 7 shows the calculation processing of the interrupt calculation routine based on the distance pulse from the distance sensor. Calculation flowchart, Figure 8 is a calculation flowchart showing detailed calculation processing of the mode calculation routine in Figure 6;
The figure is a calculation flowchart showing detailed calculation processing of the current position calculation routine in Fig. 6, Fig. 10 is a display explanatory diagram for explaining another embodiment, and Fig. 11 is a configuration showing the configuration of the present invention. It is a diagram. 1... Direction detection device, 2... Distance sensor, 3a
...Cassette tape as storage means, 3...Reading device, 4...Microcomputer, 5...
CRT controller, 6... as a display means
CRT display device, 8... map changeover switch section as a changing means.

Claims (1)

[Claims] 1. Current position detection means for detecting the current position of the vehicle, storage means for storing map data for displaying a road map, and displaying a road map based on the map data from the storage means. and display means for additionally displaying the current position detected by the current position detection means on the road map, wherein the storage means has a first memory for displaying a specific road map. Stores map data and first scale data indicating the scale of the road map, and stores second map data of the road map having a different scale with respect to the specific road map and second scale data indicating the scale of the road map. scale data, and a changing means for generating a change instruction for displaying a road map of a different scale with respect to the road map displayed on the display means; and a first scale data from the storage means. reading the second map data from the storage means to display a specific road map on the display means, and reading second map data from the storage means to display a road map of a different scale on the display means according to a change instruction from the change means. a map display control means for switching and displaying the road map; and the display means based on at least the second scale data and the first scale data stored in the storage means when the map display control means switches and displays the road map. An in-vehicle navigator comprising: current position correction means for correcting and displaying a current position displayed on the vehicle. 2. The storage means stores, for each region obtained by dividing the road map into a plurality of regions, a map number indicating the number of the region, map data of the road map in that region, and scale data of the road map in the region; Coordinate data indicating the position of the area with respect to a reference point in coordinates and map numbers of areas with different scales for the area are stored, and the map display control means is configured to store coordinate data indicating the position of the area in coordinates with respect to the reference point, and the map display control means is configured to store coordinate data indicating the position of the area with respect to the reference point in coordinates, and map numbers of areas with different scales with respect to the area, Based on the map numbers of areas with different scales stored in the storage means, map data stored corresponding to the map numbers is read from the storage means, and road maps with different scales are switched on the display means. and the current position correction means, when switching display by the map display control means, compares the scale data and coordinate data stored in the storage means corresponding to map numbers of areas with different scales with the scale data and coordinate data before switching display. 2. The in-vehicle navigator according to claim 1, wherein the current position displayed on the display means is corrected and displayed by performing coordinate transformation using scale data and coordinate data for the display area. 3. The storage means stores a map number of an enlarged area with a larger scale than that area and a map number of a reduced area with a smaller scale than that area, as map numbers of areas with different scales for that area, The changing means generates a change instruction for enlargement or reduction, and the map display control means, in response to the change instruction for enlargement or reduction from the change means, changes the enlarged area or area according to the change instruction. 3. The in-vehicle navigator according to claim 2, wherein map data corresponding to a map number of the reduced area is read from the storage means and the area is displayed on the display means. 4. The storage means stores a plurality of map numbers of enlarged regions that are enlarged for each region obtained by dividing the region into a plurality of regions, as map numbers of enlarged regions having a larger scale than the region, and controls the map display. The means selects a map number of an enlarged area of the area where the current position display is located from among the plurality of divided areas when an enlargement instruction is issued from the changing means, and converts the map data of the selected map number into the 4. The in-vehicle navigator according to claim 3, wherein the road map of the enlarged area is read from the storage means and displayed on the display means.