Communications: electrical – Vehicle position indication – Map display
Reexamination Certificate
1999-09-24
2001-10-23
Lee, Benjamin C. (Department: 2736)
Communications: electrical
Vehicle position indication
Map display
C340S990000, C701S212000
Reexamination Certificate
active
06307485
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a map display unit that utilizes, for example, global positioning system (GPS) satellites to measure its present position and displays a mark representing the present position along with map information, and more particularly to a map display unit suitable for carrying.
DESCRIPTION OF THE RELATED ART
As shown in
FIG. 8
, a navigation system mounted in a vehicle is constructed of a GPS antenna
1
, a GPS receiver
2
, a navigation control section
3
, a CD-ROM drive unit
4
, and a display unit
5
. Radio wave
7
from each of a plurality of GPS satellites
6
is received with the GPS antenna
1
. The received signal is modulated with the GPS receiver
2
in order to measure the present position of the system. Also, the navigation control section
3
synthesizes a mark representing the present position and the map information read out from the CD-ROM drive unit
4
. The synthesized information is sent to the display unit
5
to give the driver or the passenger visual route guidance. The vehicle navigational system, however, is bulky and unsuitable for carrying.
Hence, there is a portable GPS receiver can be carried. In a GPS receiver without a CD-ROM drive unit so an example, as illustrated in
FIG. 9
, only necessary map information is downloaded from the map server
8
to a GPS receiver
9
. The map server
8
employs, for example, a personal computer. A map disk
11
is shoved into the CD-ROM drive unit
10
of the map server
8
. Then, the map server
8
executes a predetermined application program to transmit the map information included in the selected range to the GPS receiver
9
. The transmitted map information is stored in the semiconductor storage memory of the GPS receiver
9
. Thereafter, the stored map information is carried by the GPS receiver
9
and used for displaying a map.
Incidentally, the map disk
11
stores map information on various reduced scales from one which can overlook the entire territory to one which can overlook a partial region so that the shape of a building, etc. can be pinpointed, even when limited to Japanese territory, for example. For this reason, the map information transmitted to the GPS receiver
9
includes the map information on various reduced scales in the selected range. For instance, when the “Hokkaido” district is selected, the map information includes a wide-area map (small scale-far-off view) of the entire district, a sectional map(medium scale) of each section, and a detailed map(large-scale-close-up view) of each city, etc.
Carrying information about maps different in educed scale is easy to use. The reason is that a small-scale map of a large area is easy to view in planning a route, while a large-scale map of a small area is easy to view at a place near an intermediate point or a destination.
However, since it takes time and labor to change a reduced scale frequently and operability is poor, there is room for improvement in easiness of use.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a map display unit that is capable of reducing the number of map selection operations on different scales in order to improve its operability.
To achieve the foregoing objects and in accordance with one important aspect of the present invention, there is provided a map display unit that comprises (1) position detection means for detecting its present position, (2) storage means for storing map information on various scales, (3) extraction means for extracting map information including the present position detected by the position detection means from the storage means in accordance with a predetermined extracting rule, (4) display control means for synthesizing a mark representing the present position and the extracted map information and then displaying them on display means, and (5) set means for setting the extracting rule. The set means sets a first rule for most preferentially extracting map information on the largest scale and a second rule for most preferentially extracting map information on a specified scale.
The present invention is provided with the set means that sets a rule for extracting map information from the storage means. The set means sets a first rule for most preferentially extracting map information on the largest scale and a second rule for most preferentially extracting map information on a specified scale. For this reason, if the first rule is set, a map on the largest scale having detailed information can be displayed, even if a map were switched. Therefore, the accuracy of route guidance can be enhanced by displaying a map suitable when passing through complicated geographical features or city. On the other hand, if the second rule is set, an arbitrary scale can be specified. For example, if a map on the smallest scale is specified, it can overlook a wide range of area and therefore the entire planed route can easily be grasped.
In another important aspect of the present invention, there is provided a map display unit that comprises (1) position detection means for detecting its present position, (2) storage means for storing map information on various scales including a predetermined map on a predetermined scale which must overcome a barrier in order to move out of the predetermined map, (3) extraction means for extracting map information including the present position detected by the position detection means from the storage means in accordance with a predetermined extracting rule, (4) display control means for synthesizing a mark representing the present position and the extracted map information and then displaying them on display means, and (5) set means for setting the extracting rule. The set means sets a first rule for most preferentially extracting map information on the largest scale and a second rule for most preferentially extracting map information on a specified scale.
According to the present invention, the storage means stores map information on various scales including a predetermined map on a predetermined scale which must overcome a barrier in order to move out of the predetermined map. When a corresponding map is not present, the predetermined map can be displayed instead. As a result, a blank map display can be eliminated.
In a preferred form of the present invention, the set means further sets a third rule for having a user select displayed scales of corresponding maps and also extracting map information on the selected scale.
According to the preferred form of the present invention, a map on a desired scale can be selected and displayed, each time a map is switched. Although time is taken, a map on an optimal scale can always be displayed.
In another preferred form of the present invention, the map display unit as set forth in claim
1
, wherein the set means sets a fourth rule for extracting a map on the second-largest scale in corresponding maps when a map on the largest scale is not present in the corresponding maps in setting the first rule, and also displays a message indicating that the scale of the map has been changed.
According to the preferred form of the present invention, in the case where a map on the largest scale is not present in corresponding maps, a map on the second largest scale in the corresponding maps is displayed and a message indicating the change of the reduced scale is displayed. Therefore, a blank map display can be avoided and the change of the reduced scale can be grasped.
In still another preferred form of the present invention, the map display unit as set forth in claim
1
, wherein the set means sets a fifth rule for having a user select one of displayed scales of corresponding maps when a map on a specified scale is not present in the corresponding maps in setting the second or third rule and also for extracting a map on the selected scale. The set means also sets a sixth rule for displaying only the present-position mark without extracting the corresponding maps when the scales of the corresponding maps are not selected.
According to the preferred form of the present i
Blank Rome Comisky & McCauley LLP
Jatco Corporation
Lee Benjamin C.
LandOfFree
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