U.S. patent application number 09/742734 was filed with the patent office on 2001-07-05 for method and navigation sytem for display of sections of a digital map data base as well as an improved operating unit and interface for same.
Invention is credited to Binnewies, Olaf, Fabian, Thomas, Hessing, Bernd, Jung, Thomas, Nordsiek, Walter, Otte, Dirk, Rentel, Bettina, Tiemann, Dirk, Winter, Stephan.
Application Number | 20010007088 09/742734 |
Document ID | / |
Family ID | 7934990 |
Filed Date | 2001-07-05 |
United States Patent
Application |
20010007088 |
Kind Code |
A1 |
Winter, Stephan ; et
al. |
July 5, 2001 |
Method and navigation sytem for display of sections of a digital
map data base as well as an improved operating unit and interface
for same
Abstract
A method, operating unit, navigation system and interface for
displaying a predetermined section of a digital map database, which
represents a real geographic area, on a display device are
described. The digital map database contains data representing
various geographic elements. An attribute, which defines a display
priority, is assigned to each geographic element. An evaluation is
then performed to determine whether or not particular geographic
elements in the predetermined section to be displayed should or
should not be visible on the display device. A particular
geographic element is made visible on the display device when it is
located in the predetermined section and when its
display-priority-determining attribute satisfies certain selection
criteria or selection rules. This method prevents display of too
many geographic elements, which would otherwise make the display
congested thus producing an unclear display.
Inventors: |
Winter, Stephan; (Hannover,
DE) ; Hessing, Bernd; (Holle, DE) ; Jung,
Thomas; (Frankfurt, DE) ; Nordsiek, Walter;
(Holle, DE) ; Binnewies, Olaf; (Hildesheim,
DE) ; Fabian, Thomas; (Hildesheim, DE) ;
Rentel, Bettina; (Giesen, DE) ; Otte, Dirk;
(Laatzen, DE) ; Tiemann, Dirk; (Hannover,
DE) |
Correspondence
Address: |
STRIKER, STRIKER & STENBY
103 East Neck Road
Huntington
NY
11743
US
|
Family ID: |
7934990 |
Appl. No.: |
09/742734 |
Filed: |
December 20, 2000 |
Current U.S.
Class: |
701/439 ;
340/995.1 |
Current CPC
Class: |
G01C 21/367 20130101;
G09B 29/10 20130101 |
Class at
Publication: |
701/208 ;
340/995 |
International
Class: |
G01C 021/32 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 30, 1999 |
DE |
199 63 764.4 |
Claims
We claim:
1. A method of displaying a predetermined section of a digital map
database, which represents a real geographic area, on a display
device, the digital map database containing map data representing
geographic elements, said method comprising the steps of: a)
selecting respective geographic elements for display according to
the predetermined section of the digital map database to be
displayed; and b) determining whether the respective geographic
elements selected in step a) are associated with corresponding
display-priority-determining attributes; and c) evaluating the
display-priority-determining attributes of the respective
geographic elements having the display-priority-determining
attributes to determine whether the respective geographic elements
in the predetermined section should be actually visible in the
display device, or not.
2. The method as defined in claim 1, wherein a number of the
geographic elements coincide with or overlap the predetermined
section and the predetermined section has a predetermined scale;
and further comprising dynamically establishing a limiting value
for the display-priority-determ- ining attributes of the respective
geographic elements to be actually visible, said limiting value
depending on the number of the geographic elements coinciding with
the predetermined section or on the predetermined scale of the
predetermined section, and actually displaying only ones of the
geographic elements having values of the
display-priority-determining attributes above the limiting
value.
3. The method as defined in claim 1, further comprising associating
corresponding value ranges of the display-priority-determining
attributes with displaying and not displaying the respective
geographic elements.
4. The method as defined in claim 1, further comprising attributing
corresponding relative overlap parameters (Z-level) to the
respective geographic elements and displaying the respective
geographic elements in the predetermined section one after the
other in order of sequentially increasing relative overlap
parameters.
5. The method as defined in claim 1, wherein the geographic
elements include streets for motor vehicles, roads for motor
vehicles, mountains, oceans, woods, buildings, restaurants, hotels
and sites.
6. The method as defined in claim 1, wherein the
display-priority-determin- ing attributes of the geographic
elements include respective travel directions, speed limits or
street signs for roads and streets.
7. The method as defined in claim 1, further comprising storing the
geographic elements of the digital map database as data on a
data-recording medium.
8. The method as defined in claim 1, wherein the
display-priority-determin- ing attributes are already correlated
with geographic elements in the digital map database or are
correlated with the geographic elements in an interface provided
between the digital map database and the display device.
9. The method as defined in claim 1, wherein relative magnitudes,
not absolute values, of the display-priority-determining attributes
are employed for selecting the geographic elements to be visible on
the display device.
10. The method as defined in claim 1, further comprising providing
at least one additional attribute for deciding whether or not to
display individual ones of the respective geographic elements in
the predetermined section.
11. A digital map database (12) representing real geographic areas,
the digital map database (12) including data regarding respective
geographic elements and corresponding attributes correlated with
the respective geographic elements, wherein at least one part of
the geographic elements is provided with respective additional
display-priority-determining attributes defining corresponding
display priorities for said at least one part of the geographic
elements, the additional display-priority-determining attributes
determining whether or not the geographic elements in a
predetermined section of the digital map database are actually
visible or not on the display device.
12. The digital map database (12) as defined in claim 11, wherein
respective selection rules for the additional
display-priority-determinin- g attributes are provided which
correlate with certain regions of the digital map data base, said
selection rules establishing respective value ranges for the
additional display-priority-determining attributes for which
geographic elements having the additional
display-priority-determin- ing attributes within said value ranges
should or should not be visible.
13. The digital map database (12) as defined in claim 1 1, wherein
the respective geographic elements are stored as data on a
data-recording medium.
14. The digital map database (12) as defined in claim 11, wherein
the geographic elements include streets for motor vehicles, roads
for motor vehicles, mountains, oceans, woods, buildings,
restaurants, hotels and sites.
15. The digital map database (12) as defined in claim 11, wherein
the additional display-priority-determining attributes of the
geographic elements include respective travel directions, speed
limits or street signs for roads and streets.
16. The digital map database (12) as defined in claim 11, further
comprising respective relative overlap parameters (Z-level)
attributed to the geographic elements.
17. An operating unit (14) for a navigation system (100) comprising
a display device (16) for display of a predetermined section of a
digital map database (12), said predetermined section representing
a real geographic area, the digital map database (12) including map
data regarding respective geographic elements, said operating unit
(14) comprising means for evaluating display-priority-determining
attributes of the respective geographic elements, said means for
evaluating display-priority-determining attributes of the
respective geographic elements determining whether the respective
geographic elements are visible or not in the predetermined section
according to the predetermined section and according to the
display-priority-determining attributes.
18. The operating unit (14) as defined in claim 17, wherein the
means for evaluating display-priority-determining attributes
includes means for determining a limiting value for the
display-priority-determining attributes of the respective
geographic elements to be actually displayed dynamically according
to a number of the geographic elements in the predetermined section
or according to a scale of the predetermined section, so that only
ones of the geographic elements having display-priority-determining
attributes above the limiting value are actually displayed.
19. The operating unit (14) as defined in claim 17, wherein the
means for evaluating display-priority-determining attributes
includes means for correlating respective value ranges of the
display-priority-determining attributes with displaying and not
displaying the respective geographic elements.
20. The operating unit (14) as defined in claim 17, wherein
corresponding relative overlap parameters (Z-level) are attributed
to the respective geographic elements and the means for evaluating
display-priority-determi- ning attributes includes means for
displaying the respective geographic elements in the predetermined
section on the display device one after the other in order with the
relative overlap parameters thereof sequentially increasing.
21. The operating unit (14) as defined in claim 17, wherein the
geographic elements include streets for motor vehicles, roads for
motor vehicles, mountains, oceans, woods, buildings, restaurants,
hotels and sites.
22. The operating unit (14) as defined in claim 17, wherein the
display-priority-determining attributes of the respective
geographic elements include respective travel directions, speed
limits or street signs for roads and streets.
23. The operating unit (1 4) as defined in claim 17, further
comprising means for storing the respective geographic elements of
the digital map database (12) as data on a data-recording
medium.
24. A navigation system (100) for vehicles including motor
vehicles, said navigation system comprising a navigation module
(10) including means for preparing a digital map database (12) and
an operating unit (14) connected with the navigation module (10),
said operating unit (14) having a display device (16) for
displaying a predetermined section of the digital map database
(12), said predetermined section representing a real geographic
area; wherein the digital map database (12) includes data regarding
respective geographic elements and corresponding attributes
correlated with the respective geographic elements, wherein at
least one part of the geographic elements is provided with
corresponding additional display-priority-determining attributes
defining corresponding display priorities for said at least one
part of the geographic elements, the display priorities determining
whether or not the geographic elements in the predetermined section
of the digital map database are actually visible or not on the
display device (16); and wherein the operating unit (14) comprises
means for evaluating the corresponding additional
display-priority-determining attributes of the respective
geographic elements, said means for evaluating the corresponding
additional display-priority-determining attributes of the
respective geographic elements determining whether the respective
geographic elements are visible or not in the predetermined section
according to the predetermined section and according to the
additional display-priority-determining attributes.
25. The navigation system (100) as defined in claim 24, wherein the
navigation module (10) includes means for retrieving map data from
a digital map database (12) stored on a data-recording medium or
means for establishing a data link for obtaining the digital map
database (12).
26. The navigation system (100) as defined in claim 25, wherein
said data link is a radio link establishing a connection to an
externally located database device.
27. The navigation system (100) as defined in claim 25, wherein
said means for establishing said data link includes means for
receiving and integrating actual traffic information with the data
from the digital database (12).
28. The navigation system (100) as defined in claim 27, wherein
said means for receiving said actual traffic information receives
said traffic information by means of RDC-TMC.
29. An interface (18) connecting a digital map database (12) and
display means (14, 16) for displaying a predetermined section of
the digital data base (12), said digital database (12) representing
actual geographic areas and containing data regarding respective
geographic elements, said interface (18) including means for
associating corresponding display-priority-determining attributes
with the respective geographic elements during transfer of map data
from the digital map database to the display means, said
display-priority-determining attributes establishing whether or not
individual ones of the respective geographic elements in the
predetermined section of the digital database (12) are made visible
or not in the display means in accordance with the predetermined
section to be displayed.
30. The interface (18) as defined in claim 29, comprising means for
connecting an operating unit (14) of the display means (14,16) and
a navigation module (10) of a navigation system (100) with each
other.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method of displaying
sections of a digital map database, which are pictures or images of
real geographic areas, the digital map database containing data
regarding respective geographic elements. The present invention
also relates to a digital map database, which is a representation
of real geographic areas and which contains data regarding
geographic formations and respective attributes for corresponding
geographic elements. The present invention also relates to an
operating unit of a navigation system with a display device for
displaying sections of a digital map database, which are pictures
or images of real geographic areas. The present invention relates
further to a navigation system for a vehicle, especially a motor
vehicle, with a navigation module, which makes a digital map
database available, and with an operating unit connected with the
navigation module, which has a display device for display of
sections of the digital map database, especially for performing the
above-mentioned process. In addition, the invention relates to an
interface between a digital map database, which is a representation
of real geographic areas and contains data of geographic elements,
and to a display device for displaying sections of the digital map
database.
[0003] 2. Prior Art
[0004] Permanently installed navigation systems guide an operator
of a vehicle, especially a motor vehicle, aircraft or ship,
rapidly, simply and reliably to a desired destination, without
requiring the operator to acquire and study map materials and
arduously plan a route. For that purpose suitable navigation data,
for example based on chart data, land map data or street map data,
is available in the navigation system, for example, stored on
CD-ROM as a digital map database. The navigation system uses, for
example, a GPS (Global Positioning System) to ascertain its present
location in order to calculate navigation advisory messages, which
guide the operator to his or her destination. The navigation data
includes, for example, data regarding streets and roads for a motor
vehicle as well as geographic information, such as data regarding
mountains, oceans, woods, cultivated regions, buildings or other
topographic elements, or additional information, e.g. such as data
regarding restaurants, hotels, worthy sites or the like.
[0005] The digital map database is essentially a representation of
a real street network and a suitable geographic region. This
information from the digital map database is displayed on a display
device in an operating unit in order to inform the operator. The
number of geographic features and the degree of detail appearing in
the display is selected differently to obtain an easy-to-read,
clear display in different situations. For example, only major
highways are shown on an overview map. Residential street maps
should contain details up to residential buildings. The selection
of the map features to be displayed substantially effects the
readability and visibility of map sections displayed on the basis
of a digital map database. This selection of features for display
is especially important for maps displayed in a vehicle, since an
operator of the vehicle must be able to ascertain all required
information for route guidance with as brief as possible a glance
at the display device. The map display significantly cannot be set
up according to a generally established rule, but a relative
importance should be assigned to the different displayed elements.
For example, an overview map of the Ruhr region may significantly
contain only expressways or major highways. A map of Arizona in the
same scale could also contain, in contrast, comparatively smaller
roads.
[0006] In navigation systems for a motor vehicle it is significant
that the navigation module, which accesses the digital map database
is separate from the display device and is also displayed
separately. Thus the navigation module requires a predetermined
interface for accessing the digital map database. This interface
must permit setting up a digital map in different scales on the
display device that has sufficient clarity.
[0007] The interfaces for navigation systems are, for example, made
by NAVTECH (http://www.navtech.com) or ETAK Inc.
(http://www.etak.com). These interfaces provide access to the
physical memory format of the digital map database. Generally
different types of digital map databases are used in different
vehicles. Furthermore access conflicts can occur during access by
the navigation module, for example for internal route computation,
and operating unit processing, for example for production of a
display of sections of the digital map database on the display
unit. Furthermore the elements contained in the digital map
database are described as "direct", i.e. a highway or expressway is
described as a street of the class "motorway" with a number.
However it has been shown that standardization and agreement
regarding classification of map elements is possible only to a very
unsatisfactory degree which is unsuitable for display purposes.
[0008] It is not possible to perform an optimized pre-calculation
of the important displayed elements for the respective display
screen sections in the digital map database for every possible zoom
stage and every possible display. Thus the operating unit must
include means for deciding which elements should be shown and which
elements should be suppressed during production of the display. The
possible overlap of the displayed elements is an additional
difficulty, which can occur, for example, with an island in an
ocean. Also the relative overlap must be detected in the interface.
Furthermore height or elevation information is generally not
contained in the digital map database of a vehicular navigation
system.
[0009] With the standard "direct" or absolute coded digital map
according to the state of the art it is disadvantageous that the
thinning out algorithms computed in the display device are
operational only with certain physical data formats known in
detail.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide an
improved method for displaying sections of a digital map database
in a navigation system in a vehicle, which does not have the
above-described disadvantages and which dynamically adjusts the
display of the sections of the digital map database, i.e. to the
respective actual requirements.
[0011] It is another object of the present invention to provide an
improved navigation system with an improved operating unit for
performing the improved method of displaying sections of a digital
map database, which does not have the above-described disadvantages
and which dynamically adjusts the display of the sections of the
digital map database.
[0012] It is a further object of the present invention to provide
an improved interface of the above-described type and an improved
operating unit of the above-described type of the navigation system
for performing the improved method.
[0013] It is an additional object of the present invention to
provide an improved digital map database for the improved method of
displaying predetermined sections of the database in a navigation
system in a vehicle, which does not have the above-described
disadvantages and which dynamically adjusts the display of the
sections of the digital map database.
[0014] According to one aspect of the present invention the method
of displaying a predetermined section of the digital map database,
which represents a real geographic area, on a display device, the
digital map data based containing map data representing geographic
elements, includes
[0015] a) selecting respective geographic elements for display
according to the predetermined section of the digital map database
to be displayed; and
[0016] b) determining whether the respective geographic elements
selected in step a) are associated with corresponding
display-priority-determining attributes; and
[0017] c) evaluating the display-priority-determining attributes of
the respective geographic elements having the
display-priority-determining attributes in the predetermined
section to determine whether they should be actually visible in the
display device, or not.
[0018] Furthermore the above-described method provides the
advantage that an optimum "thinning out" of the displayed
information occurs for the display screen contents for display of
the predetermined section of the digital map database. The clarity
of the instantaneous display is thus adjusted for various different
views, e.g. by means of an algorithm.
[0019] Preferred embodiments of the method according to the
invention have additional advantages.
[0020] According to preferred embodiments of the method a limiting
value for the display-priority-determining attributes of the
respective geographic elements to be actually displayed is
dynamically established. The number of the geographic elements
actually coinciding with the predetermined section determines this
limiting value. Alternatively, the scale of the predetermined
section determines the limiting value.
[0021] In preferred embodiments of the method respective value
ranges for the display-priority-determining attributes of the
geographic elements that determine whether or not the geographic
elements are displayed or not are set up for the predetermined
section to be displayed. Thus the method, for example, can display
only expressways or major highway roads on the display device in
the Ruhr region of Germany, while also displaying streets and roads
with lower values of the display-priority-determining attributes on
the display device in Arizona.
[0022] When relative overlap parameters (Z-level) are attributed to
the respective geographic elements and the respective geographic
elements are added to the predetermined section to be displayed one
after the other in order of sequentially increasing relative
overlap parameters, a realistic view of a geographic area can be
preferably produced in spite of the absence of height information
in the digital map database. For example an island can have a
higher Z-level than the surrounding water. The water is then added
to the predetermined section first and then the island is shown.
Because of this aspect of the preferred embodiments of the method
it is guaranteed that the island will be visible and not covered by
the water.
[0023] The display-priority-determining attributes are either
already associated with the geographic elements in the digital map
database or in an interface connecting the digital map database and
the display device.
[0024] The respective values of the display-priority-determining
attributes of the geographic elements are preferably employed
according to their relative magnitudes and not their absolute
values.
[0025] According to another aspect of the present invention a
digital map database is provided that represents real geographic
areas. This digital map database includes data regarding respective
geographic elements and corresponding attributes associated with
the respective geographic elements. At least one part of the
geographic elements is provided with respective additional
display-priority-determining attributes defining corresponding
display priorities for each of the at least one part of the
geographic elements. The additional display-priority-determining
attributes establish whether or not the geographic elements in the
section of the digital map database to be displayed are actually
visible or not on the display device.
[0026] The digital map database according to the invention has the
advantage that an optimum "thinning out" of the visible information
in the predetermined section to be displayed on the display device
occurs. The clarity of the instantaneous display is thus adjusted
for various different views, e.g. by means of an algorithm.
[0027] Advantageous features of the digital map database are
provided in preferred embodiments.
[0028] Different parts of the digital map database can be thinned
out differently for display by providing predetermined selection
rules for the display-priority-determining attributes of the
respective geographic elements that are associated with the
respective different parts of the digital map database. The
selection rules establish respective value ranges for the
display-priority-determining attributes that determine whether or
not the geographic elements in the predetermined section are
visible on the display device. For example, then only expressways
or major highway roads can be shown on the display device in the
Ruhr region of Germany, while also streets and roads with lower
values of the display-priority-determining attributes can be shown
on the display device in Arizona.
[0029] A realistic display can be produced in spite of the omission
of height information in the digital map database when relative
overlap parameters (Z-level) are attributed to the respective
geographic elements in the digital map database. If the respective
geographic elements in the predetermined section are now made
visible on the display device in order of increasing Z-level, the
above-mentioned realistic reproduction of the appearance of a
selected geographic area is produced. For example, if an island has
a higher Z-level than the surrounding water, then the island will
be shown after the water. Thus it is guaranteed that the island it
will not be covered or obscured by the water.
[0030] According to another aspect of the present invention an
operating unit is provided that includes means for evaluating
display-priority-determining attributes of the respective
geographic elements. The means for evaluating
display-priority-determining attributes of the geographic elements
establish whether the respective geographic elements in the
predetermined section are visible in the display, or not. This
determination is made according to the predetermined section of the
map database to be displayed and according to the
display-priority-determining attributes.
[0031] This feature of the operating unit has the advantage that an
optimum "thinning out" of the display screen contents for display
of the predetermined section of the digital map database occurs.
Thus the clarity of the instantaneous display is adjusted for
different views, for example by means of a suitable algorithm.
[0032] Preferred embodiments of the operating device have various
additional advantages.
[0033] In a preferred embodiment of the operating device according
to the invention the means for evaluating
display-priority-determining attributes includes means for
determining a limiting value for the display-priority-determining
attributes of the respective geographic elements to be actually
displayed dynamically. This limiting value depends on the number of
the geographic elements in the predetermined section of the map
database or on the scale of the predetermined section, so that only
those geographic elements in the predetermined section having
display-priority-determining attributes above the limiting value
are actually displayed.
[0034] A different thinning out for different parts of the map
database can be produced when the means for evaluating
display-priority-determinin- g attributes includes means for
associating respective value ranges of the
display-priority-determining attributes with displaying the
geographic elements in the predetermined section visible, or not,
on the display device. For example, then only expressways or major
highway roads can be shown on the display device in the Ruhr region
of Germany, while also streets and roads with lower values of the
display-priority-determining attributes can be shown on the display
device in Arizona.
[0035] A realistic display can be produced in spite of the omission
of height information in the digital map database when relative
overlap parameters (Z-level) are attributed to the respective
geographic elements in the digital map database. If the respective
geographic elements in the predetermined section are now made
visible on the display device in order of increasing Z-level, the
above-mentioned realistic reproduction of the appearance of a
selected geographic area is produced. For example, if an island has
a higher Z-level than the surrounding water, then the island will
be shown after the water. Thus it is guaranteed that the island it
will not be covered or obscured by the water.
[0036] Furthermore the navigation system of the above-described
kind for performing the method according to the invention contains
the above-described digital map database and the operating
unit.
[0037] These features provide the advantage that an optimum
"thinning out" of the visible information in the predetermined
section to be displayed on the display device occurs. The clarity
of the instantaneous display is thus adjusted for various different
views, e.g. by means of an algorithm.
[0038] Various advantages are provided by preferred embodiments of
the navigation system according to the invention.
[0039] In a preferred embodiment the navigation system includes a
navigation module that stores the digital map database on a
data-recording medium or that retrieves currently required data
from a digital map database by means of a data connection,
especially a radio connection, from a location outside of the
navigation system.
[0040] Means for incorporating and retaining actual traffic
information in the data taken from the digital map database for
navigation, especially by means of RDS-TMC, is preferably provided
in the navigation system for consideration of the actual
continuously changing traffic situation for display and route
calculation.
[0041] According to another aspect of the present invention an
interface is provided that connects a digital map database and
display means for displaying a predetermined section of the digital
data base representing actual geographic areas and containing data
regarding the respective geographic elements. The interface
includes means for associating corresponding
display-priority-determining attributes with the respective
geographic elements during transfer of map data from the digital
map database to the display means. The display-priority-determining
attributes establish whether or not individual respective
geographic elements in the predetermined section of the digital
database are made visible or not in the display means in accordance
with the predetermined section to be displayed.
[0042] This has the advantage that an optimum "thinning out" of
certain display screen contents for display of the predetermined
section of the digital map database takes place. The clarity of the
instantaneous display is thus adjusted for various different views,
e.g. by means of an algorithm.
[0043] This interface preferably includes means for connecting an
operating unit of the display means and a navigation module of a
navigation system with each other.
[0044] The geographic elements include, among others, streets and
roads for motor vehicles, mountains, oceans, woods, buildings,
restaurants, hotels or sites. The attributes of the geographic
elements include, for example, travel direction, speed or street
signs for the streets and roads. Furthermore the geographic
elements of the digital map database are appropriately stored as
data on a data-bearing medium, especially a CD-ROM.
BRIEF DESCRIPTION OF THE DRAWING
[0045] The objects, features and advantages of the invention will
now be illustrated in more detail with the aid of the following
description of the preferred embodiments, with reference to the
accompanying figures in which:
[0046] FIG. 1 is block diagram of a part of a navigation system
according to the invention;
[0047] FIG. 2 is a plan view of a first section of a digital map
database shown in an exemplary display prepared according to the
method of the invention;
[0048] FIG. 3 is a plan view of a second section of a digital map
database in an exemplary display prepared according to the
inventive method; and
[0049] FIG. 4 is a plan view of a third section of a digital map
data base in an exemplary display prepared according to the method
of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0050] The navigation system 100 shown in FIG. 1 comprises a
navigation module 10 with a digital map database 12 and an
operating unit 14 with a display device 16, for example an LCD-flat
display screen. An interface 18 connects the operating unit 14 and
the navigation module 10.
[0051] All display elements are provided with a
display-priority-determini- ng attribute for the relative
"importance" of the display element in the interface 18 for
accessing the digital map 12. The term "display element" means any
geographic element of the digital map database 12, such as a
streets, road, mountain, ocean, island or wood, as well as an
additional element, such as a hotels, a worthy site, a restaurant
or the like.
[0052] This attribute specifying "importance" is actually given by
the manufacturer of the digital map database 12. It is not
objectively measured during the data inquiries.
[0053] This attribute, can be evaluated in the operating unit 14,
together with other criteria, in order to permit an optimum
"thinning out" of the display screen content for display of
portions of the digital map 12.
[0054] The manufacturer of the digital map database 12 can, for
example, provide highways with a one-place number with a
comparatively high importance or display priority and highways with
three-place numbers with a comparatively lower importance or
display priority. In another potion of the digital map database an
especially important national or state roadway, for example, can be
provided with a higher priority than a shorter highway. By giving
the relative priorities or display priorities as attributes of the
"importance" then a thinning-out algorithm can be provided by the
manufacturer, which controls the digital map data base 12.
[0055] The display elements from a digital map, as already
mentioned, are provided with relative weightings to permit the
correct generation of the displayed map data on different display
screens and in different scales. These relative weightings of the
displayed elements are used by the operating unit 14 in order to
produce a thinning out effect during a scale change or a change to
another section of the digital map database. The advantage of the
relative weightings is that the criteria for allocating the
weighting factors can be produced by the maker of the digital map
database 12 with the help of arbitrary controls and need not be
known in the operating unit 14.
[0056] The method of relative weighting or prioritizing is
applicable to all display elements of a digital map database 12. No
agreement regarding the attributes is necessary. Furthermore the
relative weightings can be added later to the input digital map
database 12. The relative weightings can also be added subsequently
to the input display elements. Standardization of the display
elements is not required.
[0057] The method can also be used with all interfaces 18 for the
digital map database 12. This interface 18 is advantageously
arranged between the navigation module 10 and the operating unit 14
in the vehicle. However it is possible to provide a wireless
interface 18 between the vehicle and data infrastructure
(telematic) by means of a wireless data connection. The data does
not necessarily need to be stored on data recording media.
Furthermore street data can be stored on a CD with some weighting
factors. Additional information in the form of traffic data may be
provided, for example, by means of RDS-TMC, and data regarding
routes are, for example, produced in the navigation system itself.
The method according to the invention is useable for all these
data.
[0058] Also a relative overlap parameter (Z-level) can also be
associated with the data. The overlap parameter specifies which
display elements should be shown in the display over other display
elements. An island, for example, is assigned a higher Z-level
parameter than the water. The display device 16 then produces the
element with the lower Z-level parameter first and then
subsequently the element with the higher Z-level parameter. Because
of that it is possible to produce nearly realistic displays of map
data without exact height information.
[0059] The aforementioned "Z-level" can be integrated in the
weighting factors, since, for example, the island has a higher
weighting factor than the water. An algorithm can be provided in
the operating unit 14, which first displays the display elements
with the lower weighting factor and, after that, the display
elements with the higher weighting factor. It is understandable
that not erroneously correlated display elements, for example, an
island and water, are separated from each other by their weighting
factors, so that they are not displayed together with their
weighting factors in the operating unit 14. In so far as an
association of areas of importance or weighting factors and the
states "display" and "do not display" occurs in the operating unit
14, the associated display elements, such as islands and water,
should be correlated with the same weighting parameter range.
[0060] Respective relative magnitudes of the display priorities are
preferably used in the display sections 20, 22, 24 and their
absolute values are not used. This should be subsequently more
understandable with the aid of FIGS. 2 to 4. These figures show
first, second and third displayed sections 20, 22 and 24 of the map
database, subsequently called display screen sections. An A-city 26
having a priority parameter value of four, a B-city 28 having
priority parameter value of three, a C-city 30 having a priority
parameter value of four and a D-city with a priority parameter
value of three are shown in the display screen sections 20, 22, and
24. The four cities 26, 28, 30 and 32 are combined with different
priority values in the digital map in three scenes.
[0061] Two selection principles or rules, which were not previously
defined for the digital map database, are now used by the display
device. These selection rules state that only two cities may appear
in a single display screen section 20, 22, 24 and the congestion of
cities in a display screen section 20, 22, 24 should be minimized.
These principles mean that not all cities near each other in a
display screen section should be displayed, but only those cities
should be shown which are furthest from each other so that the
illustrated cities are distributed as uniformly as possible on the
display screen section 20, 22, 24. In the illustrations of FIGS. 2
to 4 the city or cities that are actually shown on the display
screen are indicated with shading. The boxes without shading show
the corresponding city or cities that are not displayed.
[0062] In the first display section 20 according FIG. 2 this leads
to a relative rating of all the cities 26, 28 and 30 present in the
section for suppression of the city with the lowest priority value,
namely the B-city 28. In the second section according to FIG. 3
lesser cities 28 and 30 are displayed. In the third section 24
according to FIG. 4 there are two candidates with the same display
priority "matching candidates", namely B-city 28 and D-city 32.
With cities having the same priority parameter values the principle
"minimize the congestion of cites within the display section 24" is
employed. Thus in this latter case the B-city is suppressed.
[0063] The disclosure in German Patent Application 199 63 764.4 of
Dec. 30, 1999 is incorporated here by reference. This German Patent
Application describes the invention described hereinabove and
claimed in the claims appended hereinbelow and provides the basis
for a claim of priority for the instant invention under 35 U.S.C.
119.
[0064] While the invention has been illustrated and described as
embodied in a method, operating unit, navigation system and
interface for display of sections of a digital map database, it is
not intended to be limited to the details shown, since various
modifications and changes may be made without departing in any way
from the spirit of the present invention.
[0065] Without further analysis, the foregoing will so fully reveal
the gist of the present invention that others can, by applying
current knowledge, readily adapt it for various applications
without omitting features that, from the standpoint of prior art,
fairly constitute essential characteristics of the generic or
specific aspects of this invention.
[0066] What is claimed is new and is set forth in the following
appended claims.
* * * * *
References