Map information displaying device

Details Map information displaying device Map information displaying device

1999-10-14

2001-11-20

Lee, Benjamin C. (Department: 2736)

Communications: electrical

Vehicle position indication

Map display

C340S988000, C340S990000, C701S200000, C701S208000, C701S209000, C701S211000

Reexamination Certificate

active

06320517

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a map information display device which displays a present position of a displacement body on a map.
BACKGROUND TO THE INVENTION
Conventional map information display devices which display a present position of a displacement body on a map are known in the navigation systems or the like of automobiles.
FIG. 1
is a block diagram of a conventional map information display device such as disclosed in non-examined Japanese utility model publication JP-U-3-10278.
FIG. 2
is an explanatory diagram showing a display example displayed on a display section.
In
FIG. 1
, reference numeral
1
denotes a CD-ROM (compact disk . read on memory) in which map data is stored,
2
is an operational section into which commands are input by a user,
3
is a bearing sensor of the displacement body,
4
is a displacement amount sensor,
5
is a bearing calculation means.
6
is a processing device which performs overall control of the map information display device.
7
is a system controller,
8
is a map data buffer memory.
9
is a display device acting as a display section,
10
is a CRT (cathode ray tube) controller,
11
is a first VRAM (image random access memory),
12
is a second VRAM,
13
is a read controller,
14
is a CRT.
The processing device
6
generates images so that the present position of the displacement body is in the center and stores such images in the first VRAM. The image reading region (window) is displaced and scrolled in the first VRAM
11
depending on the displacement of the displacement body. The window is monitored to ascertain whether the map reading region has reached a preset region or not. When the preset region is reached, the generated image is stored in the second VRAM so that the present position of the displacement body is at a center. Thereafter the window in the second VRAM
12
displaces by scrolling depending on the displacement of the displacement body. Thereafter the process is repeated whereby images are generated, recorded and scroll displayed together with the displacement of the displacement body each time a region in which a window is preset in each VRAM
11
,
12
is reached.
The recording region of the first VRAM
11
(the same as the second VRAM
12
) is present in simplified form in FIG.
2
. As shown in the figure, a rear plotting initial line (hereafter back drawing line) is provided in a region which is smaller on all sides than the first VRAM
11
. A window WD
1
is provided in a region which is again smaller on all sides. The center CAR
1
of the window WD
1
corresponds to the present position of the displacement body.
The operation of the invention will be described below.
FIG. 3
is a flowchart showing the flow of map drawing processing in such a map information display device. The process device
6
reads map data corresponding to the present position of the displacement body from the CD-ROM and inputs the read data into the CRT controller
10
of the display device
9
. The CRT controller
10
generates an image so that the present position of the displacement is in the center and records the image in the first VRAM
11
(step ST
1
). Next a VRAM (first VRAM
11
) which reads the image from the read controller
13
is designated and a position of the window WD
1
of the first VRAM
11
is determined so that the cursor which shows the position of displacement of the displacement body is expressed in the center of the screen.
The read controller
13
reads a map image from the window WD
1
of the position determined for the designated first VRAM
11
and displays it on the CRT
14
(step ST
3
). Monitoring is performed to check whether the window WD
1
has reached the back drawing line BDL
1
or not. If the line has not been reached, the routine returns to step ST
2
and the process after the calculation of the window address of the window WD
1
which depends on the displacement of the displacement body is repeated (step ST
4
). In this way, the position of the window WD
1
which depends on the displacement of the displacement body is moved and the map image is displayed by scrolling.
If the displacement body has traversed a considerable distance, the window WD
1
reaches the back draw line BDL
1
, the process device
6
reads map data which depends on the present position of the displacement body from the CD-ROM
1
and inputs the data into the CRT controller
10
of the display device
19
. The CRT controller
10
generates an image so that the present position of the displacement body is in the center and stores the image in the second VRAM
12
(step ST
5
). Next a position of the window WD
2
of the second VRAM
12
is determined so that the cursor which shows the present position of the displacement body is in the center of the screen and that address is input into the read controller
13
(step ST
6
).
The read controller
13
reads the map image from the window WD
2
at a determined position for the designated second VRAM
12
and expresses the map in the CRT
14
(step ST
7
). Monitoring is performed to check whether the window WD
2
has reached the back drawing line BDL
2
or not. If the line has not been reached, the routine returns to step ST
6
and the process after the calculation of the window address of the window WD
2
which depends on the displacement of the displacement body is repeated (step ST
8
). In this way, the position of the window WD
2
which depends on the displacement of the displacement body is moved and the map image is displayed by scrolling.
If the displacement body has traversed a considerable distance, the window WD
2
reaches the back draw line BDL
2
, the routine returns to step ST
1
and repeats the process after the storing of the map image in the first VRAM
11
.
Apart from the above noted technique related to a conventional map information display device, published patent applications JP-A-7-218279 and JP-A-7-286857 are also noted.
Since the conventional map information display device is constructed as above, the icon (present position mark) which shows the present position of the displacement body is in the center of the display. Normally from the point of view of the driver who is driving the displacement body, information about the proximity of the displacement body is required when the displacement body is travelling at low speeds and information further forward is required at high speeds. It is advantageous to have information about areas forward of the displacement body at a wider range a high speeds than at low speeds. However in the conventional map information display device, the icon which displays the present position of the displacement body is displayed in the center and the driver can thus obtain map information regarding the environs of the present position. Thus the problem has arisen that it is difficult to display a map screen as desired by the driver.
The present invention is proposed to solve the above problems and has the object of providing a map information display device with a front extended display by which a driver can obtain information at a wider range at high speeds than at low speeds.
DISCLOSURE OF THE INVENTION
A first exemplary embodiment of the present invention allows variation of the position on the screen of the present position of the displacement body which is displayed on the display section depending on an operational state of the displacement body. In this way, the present position of the displacement body may be displayed in the center of the screen of the display section depending on an operational state of the displacement body. For example, an operational state may be the region or type of road currently traveled or displacement body speed. The present position may be also displayed in an extended front display without complicated operations.
A second exemplary embodiment of the present invention allows the present position of the displacement body on the screen which is displayed on the display section to vary depending on the speed of the displacement body. In this way, the present positio

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