JPH03137680A - Navigation device for moving body - Google Patents

Abstract

PURPOSE:To enhance the safety by avoiding a misleading color by displaying a principal road, a non-principal road and a background in different colors or displaying only the principal road in a different color, when a first and a second color code storage means are selected at the time when a vehicle is stopping and moving, respectively. CONSTITUTION:At the time of starting an automobile, a departure spot is set onto an area map by operating a navigation 11, and when a switch SW1 is operated, a menu, and a set pattern of a map selection and the present position are displayed on a CRT 26. When a vehicle runs and it is decided that it is running, a second color code storage means (second frame memory) in a CD ROM 25a is selected, based on a detecting signal of the vehicle, and only a principal road is displayed in a color being different from a background. On the other hand, when the automobile stops, a first color code storage means (first frame memory) is selected, and the principal road, a non-principal road and the background are displayed in different colors.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a navigation device installed in a moving body such as an automobile, and in particular displays a map, the current position of the automobile, and a travel trajectory on a display such as a brown tube. The present invention relates to a navigation device for a mobile body that provides driving information to a driver by displaying the following information.

[Conventional technology]

Navigation devices installed in moving objects such as automobiles are
Generally, a national map, a regional map divided into multiple parts, etc. is stored as map information in a map storage means, and the above map information is read out in response to an operator's request and displayed on a display such as a brown tube. It now provides a map for driving.

In addition, by calculating the current position of the vehicle based on detection signals from a distance sensor that detects the distance traveled by the vehicle and a direction sensor that detects the heading direction, the current position of the vehicle is displayed on the map displayed on the display. A triangular mark indicating the position and the driving trajectory are displayed as a plurality of consecutive points, so that the vehicle's position on the map on the screen can be visually confirmed (for example, Japanese Patent Application Laid-Open No. 58-53711, Japanese Patent Publication No. 59-1983). 39
See Japanese Patent Publication No. 800 and Japanese Unexamined Patent Publication No. 165511/1983.

) In this type of device, when displaying a map on the screen, the line diagrams on the map, such as various roads, rivers, bridges, etc., are displayed in different colors on the map. A line diagram is stored as a plurality of line diagram data different from the background color of the map. For example, when the background color is blue, arterial roads such as national highways and local main roads are colored red, and non-arterial roads such as general local roads and alleys are colored green, so that each road can be clearly identified. There is.

[Problem to be solved by the invention]

However, in the above-mentioned conventional device, when viewing the map on the screen while driving, the driver's attention may be impaired and safety may be reduced. That is, when a driver wants to confirm his/her destination, he ordinarily stops the vehicle and confirms the route from the main road to the detailed road on a map. When driving, the driver sometimes visually checks the main road while driving.

Therefore, there is no problem in looking at the map on the screen while the vehicle is stopped, but when you look at the map on the screen while driving, you will be able to see detailed non-arterial roads, which can be confusing. The time it takes to check this can lead to inattention to the road ahead, which may impede safe driving.

This invention has been made in view of the above-mentioned problems.The background of the map and the road, which are displayed in a different color from the display screen, are displayed in different colors when the moving object is stopped, and when the moving object is moving, the map background and roads are displayed in different colors. By displaying the background color of the road and non-arterial roads in the same color, the purpose of the J-1 program is to prevent confusing information from being given to the driver of a mobile vehicle and increase safety during driving. I-7 [Means for Solving the Problem] The mobile navigation device according to the present invention uses map data that stores arterial road data and non-arterial road data in which arterial roads and non-arterial roads in a map are respectively coded. a storage means, a display having a screen for displaying a map, a color code provided corresponding to each of the arterial roads and non-arterial roads, and a color code showing the display color of each road and a color code showing the display color of the background; A first color code storage means is provided corresponding to the arterial road, the non-arterial road, and the background, and stores a color code indicating the display color of each of the roads and the background, and stores at least the color code of the non-arterial road and the background. a second color code storage means in which each color code of the background is the same and is combined in such a way that this color code is different from the color code of the main road; a movement detection means for detecting whether or not a moving body is moving; selection means for selecting the first color code storage means when the moving body is not moving and the second color code storage means when the moving object is moving; Drawing that reads out the data and non-arterial road data, reads out the color code and background color code corresponding to each of the roads stored in the color code storage means selected by the selection means, and draws the map on the display device. It is equipped with the means.

[For production]

In this invention, when the moving object is not moving,
A first color code storage means is selected.

Along with this, color codes for arterial roads and non-arterial roads and color codes indicating the display color of the background of the screen are read out and drawn on the screen. Therefore, the main roads, non-arterial roads, and background colors are displayed in different colors on the screen.

On the other hand, when the moving object moves, the second color code storage means is selected. Accordingly, at least a color code is read out and drawn that is a combination of color codes in which the non-arterial road and the background color have the same color code and are different from the color code of the main road. Therefore, when the mobile object is moved, non-arterial roads are erased from the screen, and only the arterial roads are displayed in a color different from the background.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is an overall configuration diagram of a mobile navigation device, FIG. 2 is a front view of a display, and FIG. 3 is a schematic configuration diagram for explaining the present invention in detail.

In the figure, (1) is a control section with 110 various circuits (
2), (3), (4) and input/output ports (5), (6
), a CPU (71), a CRT-C (91, etc.) are operated by receiving stabilized power from the vehicle battery via a constant voltage circuit, and control various devices.

(2) is the first I10 interface circuit, which includes a navigation (kl) that guides the driving of the vehicle, a traffic information (12) that receives road conditions, and a wireless telephone (13) for the car.
), air conditioner for indoor air conditioning (14), television (15) as a video and audio source, radio (16), tape (17), CD (18), etc., using function switches (SWI) to (SW8). It is possible to select it via .

These function switches (SWI) to (SW8) are installed on the front panel (26b) of the CRT (26) shown in FIG.
The drive signal is sent to the CPU by pressing the button.
(7) to operate each device.

In addition, the first I10 interface circuit (2) includes:
A GP that receives radio waves from artificial satellites via an antenna and can confirm and determine the current location and moving speed of a vehicle.
The S device (19) and a flux-kent type geomagnetic detector fixed to the vehicle separate and detect the geomagnetic field into a component in the vehicle's traveling direction and a component perpendicular to the component, and a signal corresponding to this component is sent to detect the component in the vehicle's traveling direction. A direction sensor that outputs the direction θ (
20) are connected.

(3) is the second 110 interface circuit, and a vehicle speed sensor (not shown) is a movement detection means that detects the rotation of the wheel using an electromagnetic pickup, reed switch, etc.
A distance sensor (21) that outputs a pulse signal proportional to the number of rotations of the wheel is connected. Note that the azimuth sensor (20) and distance sensor (21) constitute a current position detecting means that can obtain current position data of the vehicle and also obtain travel trajectory data. (4
) is a third I10 interface circuit, to which video/audio equipment such as a television tuner (22), radio tuner (23), tape deck (24), and CD deck (25) are connected. In this CD deck (25),
A CD-ROM (25a) is provided as a map storage means, and when the navigation aυ is selected, various map information and line diagram data, etc., which will be described later, are read out and stored on the CRT.
(26) can be displayed. In addition, the above CD-R
OM (25a) includes NIKKBl, ELEC
TRONICS, November 26, 1987 issue (NO
The memory for storing map information described in 434) is adopted, and map information such as national maps, local maps, regional maps, and even district maps is stored as vector data. In addition, in this example, the map is a wide area with different scales,
There are three types of map information: standard and detailed, and this map information is stored so as to include common areas. The above district map is divided into four areas corresponding to the four quadrants of the screen (26a) of the CRT (26), and the four map blocks are considered as partial maps, and the l map block that is a part of this partial map is The data is used as map information on the above CD-R so that 4 times the data becomes the background of the CRT (26) screen (26a)
They are sequentially stored in the OM (25a). In addition, line diagrams connecting points on this district map, such as line diagrams showing roads, rivers, bridges, etc., are decomposed into line diagram data and stored, as well as character data such as letters and symbols, and service symbols. Service data of hotels, golf courses, etc. is also stored. For specific items such as roads, rivers, and bridges, color palettes are stored with multiple color codes in order to display them in various colors. In the case of roads, arterial roads such as national highways and major local roads are treated as main roads, and non-arterial roads such as local roads and alleys are displayed as detailed roads, and each is displayed in a color different from the background of the screen (26a). In order to do this, each item is stored in correspondence with a pallet number θ to 15, as shown in Table 1 below.

Moreover, in order to be able to display the above-mentioned items in other colors in addition to this color code, it has a plurality of memory tables in which a large number of color palettes are stored in color codes. Further, dot data for applying a shadow to the screen (26a) and dot data for applying a shadow to an area where an icon, which is a touch pattern, is displayed on the screen (26a) are stored, respectively.

(7) is the CPU, and the function switch (
The operation of the video/audio equipment is controlled based on the selection operation of SWI) to (SW8), and the operation of the above-mentioned CD-ROM (2) is controlled.
A control signal for reading map information etc. from 5a) and displaying it on the screen (26a) of the CRT (26) is sent to the CRT-C.
f9).

It also receives a pulse signal from the distance sensor (21), a GPS signal from the GPS device (19), and a digital signal of X and Y components from the direction sensor (20) via the TRT (interrupt circuit) (7a). Then, arithmetic processing is performed to determine the travel trajectory and current position, which are travel route information, and a display signal is output.

(8) is a temporary storage RAM which is a time storage means, and as shown in the schematic diagram of FIG. Power is constantly backed up from the on-vehicle battery so that read data can be temporarily stored and retained. When map information is read out, line drawing data is also read out, and when a desired map is selected, data is taken out so that various line drawings are superimposed on the map. In addition,
This RAM (8) contains coordinates (X) of the current position stored in the first memory table of the CD-ROM (25a).
O, YO) is stored in the center of the screen (26a), and when this current position data is read out, the screen (26a)
The current position mark (M) is displayed at the center of the screen. Also, the screen (26a) of the above CRT (26)
In order to display the travel trajectory, the memory table is provided to store position data, and in this example, the CDφROM
(25a) It has a plurality of endless memory tables corresponding to the map information of maps of different scales stored in (25a).

(9) is a CRT which is a display control means and a drawing means.
C (CRT controller) receives a command for outputting a display signal from the CPU (7) and expands the driving route information into the display RAM (10), and also stores the expanded map data and character data. It also outputs video signals and synchronization signals for displaying travel route information and the like on the CRT (26). In addition, the above CP
U (7) stores map information corresponding to one designated scale among the above four map blocks, such as partial map information, wide area, standard and detailed map information stored in the CD-ROM (25a), and this map information. Travel locus information comparable to map information is read from the memory table of the RAM (8), and the travel locus is displayed superimposed on a diagram on the map.

(10) is a display RAM that stores additional information such as the map number and scale type, as well as pattern data for displaying the operation keys that drive the various devices mentioned above as touch switches on the screen (26a). has been done. This pattern data includes the current position mark (M) displayed as a triangle on the screen (26a) of the CRT (26) (see Figure 3).
, a trajectory display pattern which is a first mode for displaying the running trajectory as a plurality of consecutive points (dots), and a trajectory non-display pattern which is a second mode in which the displayed trajectory is erased from both sides (26a). , is stored as a switching means, that is, a touch switch, which provides a switching signal to the CPU (7).

Although not shown, there is also a scroll key pattern constituting a map moving means for arbitrarily moving the map displayed on the screen (26a), and the current position mark (M) displayed on the screen (26a). A correction position mark that is a correction position mark display means for correcting a position, a return pattern that is a map movement return means for returning a moved map to its original position, and when the current position mark (M) is moved 1. The above correction. A correction pattern, etc., which is a current position mark correction means for moving the current position mark to the position of the current position mark, is stored. In addition, illustrations are omitted or enlargement to specify the scale of the map,
Reduction patterns and the like are also stored.

Next, the CRT (7), CRT-Cf91, and display RAM (101) will be explained in detail with reference to FIGS. 11 and 12.

In FIG. 11, (7b) is a display control unit (MPU) of the CPU (71), a data control unit (not shown) and a CR
It sends and receives signals to and from the CRT (9).
A display signal is output to C(9). (9) is a CRT
-C, which receives the display signal and transmits the map data, driving route information, character data, etc. to a CRT (2
6) generates a horizontal synchronizing signal (H3YNC) and a vertical synchronizing signal (VSYNC) for display. (3I) is the first frame memory, which has multiple memories in which various map information corresponds to the three primary colors (red, green, blue), and when the above map data is output one after another, the map changes to color. It is now displayed in .

Reference numeral (32) denotes a second frame memory, which stores current position data, travel trajectory data, etc. as the travel route information. Parallel/serial converters (33) and (34) convert parallel signals from the first and second frame memories into serial data using a dot timing lock, respectively. (35) is a multiplexer which transmits the address signal from the CRU (7) and the address signal from the CRT/C (9) to the CPU.
It is switched by the command signal in (7), and a signal designating a palette number is given to a color palette 36, which will be described later. (36) is a color palette, the details of which will be explained based on FIG.

This color palette (36) stores a plurality of color codes having table colors in which different color codes (RGB codes) are assigned for each item such as arterial roads, non-arterial roads, etc., corresponding to the palette numbers in Table 1 above. Means are provided. That is, for each item and color code in the first color code storage means (table 1), 0OFH, which indicates red, corresponds to the main road with pallet number 0, and 0OFH, which indicates red, corresponds to the non-arterial road with pallet number 1. FOF showing green color
H is assigned to each. Hereinafter, color codes are sequentially assigned to items corresponding to each palette number, and palette number 15 indicating the background of the screen (26a) is assigned an RGB code 888H indicating blue. Next, regarding the second color code storage means (Table 2), the color code of the non-arterial road and the background is the same as the color code 8 of the first color code storage means.
88H, while only the main road color code 0OFH is a different combination.

Further, in this example, the color codes 0OFH and 888H are different for at least the main road and the background color, and a plurality of color code storage means (table N) having table colors that are various combinations of color codes are provided for other items. ing.

It should be noted that each of the color code storage means described above is switched and selected by a selection means. This selection means provides a switching signal to the CPU (71) based on a detection signal from a vehicle speed sensor which is a movement detection means, and selects and reads any color code storage means of the color palette (36). When the vehicle is moving, the second color code storage means is selected, and when the vehicle is not moving, the first color code storage means is selected. Furthermore, when the vehicle is not moving, the second color code storage means is selected. In this case, it is possible to select a desired color code storage means using a manual switch.That is, the manual switch is a changeover switch consisting of a movable contact and a plurality of changeover contacts, although not shown. The above CRT (26
) is provided on the front panel (26b) of the CPU (7), and a switching signal can be given to the CPU (7) by manual operation to select an arbitrary color table.

By the way, (26) shown in FIG. 1 is a display device,
Image symbol (H3YNC) from CRT-C (9) above
) and a synchronization signal (VSYNC) to display a map of a specific area, driving route, current location, etc. in color. In addition, various operation keys of the touch switch section, which will be described later, are displayed in a predetermined touch area, and it is also possible to turn on the TV tuner (22) and display TV images by pressing the function switch (SW5). There is.

(27) and (29) are connected to the CPU via the output port (6).
(7) is a light emitting unit connected to the CRT (26), and (28) and (30) are light receiving units connected to the CPU (7) via the input port (5). and
It constitutes the touch panel section of the touch switch. Although not shown, this touch panel section is divided into a large number of touch areas in the row direction and column direction, and when a specific touch area among these touch areas is touched, the touch area in the row direction Infrared light passing through the intersection with the column direction is cut off, and drive signals giving various instructions are output. Specifically, the screen (26
If you touch a), the above operation pattern will be displayed on the inner periphery of the screen (26a), and if you touch any of these patterns, you can set the operation start and stop of each device, and set the time, numerical value, etc. It is something that can be done.

Next, the operation of the mobile navigation device configured as described above will be explained with reference to the flowcharts shown in FIGS. 4, 8 to 12.

First, when a key switch is turned on at the start of driving a car, the electric system of each part becomes operational by receiving power from the car's on-board battery. When the CPU (7) of the control unit (1) is powered on, it is activated by the stabilized power supply and the fourth
Initialization is performed in step 311 of the flowchart shown in the figure, and the arithmetic processing shown in the main routine of the same figure is repeated at a cycle of about several tens of milliseconds. Next, function key processing is performed in step SI2, and then,
Touch switch input processing is performed in step S13. At this time, in step S14, for example, when the operator presses the function switches (SW6), (SW4) of the radio (16), air conditioner (14), etc., the process proceeds to step S15, and the screen of the CRT (26) (
In 26a), a radio mode pattern as shown in FIG. 5 or an air conditioner mode pattern as shown in FIG. 6 is displayed. Then, by touching the area of the switch pattern provided on the display screen of each mode, the selected device can be operated at the desired set speed. Note that even during such an operation, the process proceeds to step S16,
The CPU (71 executes current position calculation processing, etc.).

First, as shown in the flowchart of FIG. 8, when a pulse signal is output from the distance sensor (21), in step S21, an interrupt calculation of the current position is performed at a predetermined time interval. At this time, pattern data is read out based on the above calculation results, and a mark (
M) is displayed on the screen (26a) and updated over time. Then, in step 323, the current position data and traveling trajectory data obtained by this calculation are sequentially stored in the temporary storage RAM (8). Thereby, when the automobile starts traveling, travel route information such as the travel distance to the current position and the travel trajectory can be obtained.

First, when the car is driven, a pulse signal is output from the distance sensor (21) as shown in the flowchart of FIG.
given to. Then, this CPU (7) adds the number of pulses N and calculates the distance traveled up to the present time (
Step 531).

Next, as the automobile travels, an interrupt processing routine shown in the flowchart of FIG. 1O is started.

First, in step S41, for a certain period of time, for example, 1
Read the number of pulses N from the vehicle speed sensor every second.

Next, in step S42, the number of pulses N at this time,
By multiplying by the unit traveling distance d, for example, 39.25 cm, the traveling distance for each fixed period of time is determined.

Then, in step 343, the direction θ from the direction sensor (20) is read.

Subsequently, in step S44, this direction θ and the travel distance θ are determined.
The position of the vehicle on the two-dimensional coordinates is determined from the following equation.

After this, in step 345, the coordinates calculated above (△X,
The current position (x, y) of the vehicle is determined from the coordinates (xo, YO) of the starting point using the following equation.

As a result, the distance traveled to the current position, which changes every moment, is obtained, and the latitude and longitude are determined at regular intervals, making it possible to know the current position (x, y). Note that this data is sent to temporary storage RAM (8) and stored sequentially, but in this RAM (8), the current position (x
, y) is written, while old data is erased one after another, resulting in a so-called endless method. Furthermore, even if the vehicle is stopped and the key switch is turned off, the current position (x, y) and distance traveled data can be retained.

Note that in step S46, the count of the number of pulses N is cleared. Then, proceeding to step 347,
Upon receiving the GPS signal from the above GPS device (19), the
Arithmetic processing for performing S processing is executed. As a result, the absolute values of the latitude and longitude are determined every fixed period of time, for example, every second, so that the traveling route information can be corrected.

Thereafter, in step 34B, both vehicle speeds V are determined from the travel distance and the timer interrupt time ΔT, for example, 100 m5ec.

By the way, when starting the car, the user operates the navigation system (11) to set the starting point at predetermined geographical coordinates, for example, one's home on a detailed district map.

Now, when the function switch (SWI) of the navigation (11) is pressed, a menu is displayed on the screen (zea) of the CRT (26) as shown in Figure 7, allowing you to select the map and the current location. The setting pattern that is the touch area is displayed.

As a result, the map display mode is started, and step S5
When the menu is displayed on the screen (26a) in 1,
When the map selection setting pattern is touched, the map information is read out from the first frame memory (31) that stores the map information, and as shown in FIG.
The desired map will be displayed on the screen (26a) of (26).

By the way, in the navigation, the arithmetic processing shown in the flowchart of FIG. 8 continues, and step S
At step 23, it is determined whether or not the vehicle is running.

Here, if it is determined that the vehicle is running, the second color code storage means is selected based on the detection signal of the vehicle.

Then, as the map information is read out and drawn on the screen (26a), the table colors in the second color code storage means are read out and displayed superimposed on the map. At this time, since the non-arterial roads have the same color as the background color, only the arterial roads (Ll) are displayed on the screen (26a), as shown in FIG. 13(a).

On the other hand, if the vehicle is not running, the map and items are displayed in the color (table color) of the color code storage means selected last time (step 25).

Next, in step 326, it is determined whether the selector switch has been selected. Here, if there is no switch operation, the previous color is displayed, but when a selection operation is performed, the color code storage means corresponding to the number of the switch is selected.

At this time, when the first color code storage means is selected (step 527), the color code of the detailed road is switched and drawn in the color of table l, that is, the color of the first color code storage means. As a result, as shown in FIG. 13(b), on the screen (26a), arterial roads (L) and detailed non-arterial roads (L2) in a color different from the background color are superimposed on the map.

As described above, this embodiment includes a first color code storage means that stores an RGB code indicating the display color of major arterial roads and detailed non-arterial roads, and an RGB code indicating the background color; and a second color code storage means having the same background color code and various combinations of this color code and highway color codes, and a plurality of color code storage means having various combinations of a large number of color codes. Then, items of different colors can be displayed on the screen (26a) by selectively switching the color code storage means based on a detection signal from the moving means, which is a vehicle speed sensor. Therefore, while the vehicle is running, the non-arterial roads are made the same color as the background color and are erased from the screen (26a), and only the main roads are displayed, while when the vehicle is stopped, the map in the desired color is displayed on the screen (26a) by the user's manual operation. ) can be displayed. Therefore, when you need to look at a map while driving, you can avoid the problem of losing attention due to lack of confusion, and improve visibility by being able to change the color tone according to changes in the surrounding environment. It has an effect that leads to safe driving.

〔Effect of the invention〕

In this invention, when the moving object is stopped, the first color code storage means is selected and the main roads, non-arterial roads, and background colors are displayed on the screen in different colors, so that the details of the map can be clearly seen. You can see it all the way. On the other hand, when the mobile object moves, the second color code storage means is selected, and at least the non-arterial road and the background color are the same color, and only the arterial road is displayed in a different color. As a result, if the moving object is a vehicle, detailed non-main roads are erased while driving,
Only the main roads can be seen, so when drivers look at the map as needed, they get distracted by the confusing complexity of the diagram and end up not paying attention to the road ahead.

This has the effect of avoiding such problems and leading to safer driving.

[Brief explanation of the drawing]

1 to 13 show an embodiment of the present invention,
Fig. 1 is an overall configuration diagram, Fig. 2 is a front view of the display, Figs. A flowchart showing the entire arithmetic processing of the routine, Figures 5 to 7 are explanatory diagrams of various menus displayed on the display screen, Figure 8
FIG. 9 is a flowchart showing calculation processing for displaying the current position of navigation and map display; FIG. 9 is a flowchart showing calculation processing based on the distance pulse from the distance sensor;
Figure 1θ is a flow chart showing an interrupt calculation routine based on the distance pulse from the distance sensor and the signal from the direction sensor, Figure 11 is a detailed electrical block diagram of the control section in Figure 1, and Figure 12 is , detailed illustrations of the color palette, and FIGS. 13(a) and 13(b) show screens of maps and diagrams displayed on the display. In the figure, (1) is the control unit, (7) is the CPU, (8)
(9) is a time storage means (RAM), and (9) is a drawing means (CRT).
-C), α0) is display RAM, (11) is navigation, (20) is direction sensor, (21) is distance sensor, (25a) is map data storage means (CD-ROM)
, (26) is a display (CRT), (31). (32) is a frame memory, (35) is a multiplexer, (36) is a color palette, (Ll) is an arterial road (main road), and (L2) is a non-arterial road (detailed road). In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A map data storage means that stores arterial road data and non-arterial road data in which arterial roads and non-arterial roads in the map are coded, respectively, a display device having a screen for displaying the map, and the arterial roads and non-arterial roads mentioned above. a first color code storage means provided corresponding to each of the non-arterial roads and storing a color code indicating the display color of each road and a color code indicating the display color of the background; and the background, respectively, and stores a color code indicating the display color of each of the roads and the background, and at least each color code of the non-arterial road and the background is the same, and this color code and the color code of the arterial road are stored. a second color code storage means which is combined to be different from the first color code, a movement detection means for detecting whether the moving object is moving or not, and a first color code when the moving object is not moving according to the movement detection means a selection means for selecting the second color code storage means when the storage means is moving; and a selection means for reading out the arterial road data and non-arterial road data from the map data storage means, and selecting the color code selected by the selection means; A navigation device for a moving body, comprising a drawing means for reading out color codes and background color codes corresponding to each of the roads stored in a storage means and drawing the map on the display.