U.S. patent application number 10/075208 was filed with the patent office on 2004-10-28 for method for transmitting location information on a digital map, apparatus for implementing the method, and traffic information provision/reception system.
This patent application is currently assigned to Matsushita Electric Industrial Co., Ltd.. Invention is credited to Adachi, Shinya, Miyama, Satoko.
Application Number | 20040215387 10/075208 |
Document ID | / |
Family ID | 33297761 |
Filed Date | 2004-10-28 |
United States Patent
Application |
20040215387 |
Kind Code |
A1 |
Adachi, Shinya ; et
al. |
October 28, 2004 |
METHOD FOR TRANSMITTING LOCATION INFORMATION ON A DIGITAL MAP,
APPARATUS FOR IMPLEMENTING THE METHOD, AND TRAFFIC INFORMATION
PROVISION/RECEPTION SYSTEM
Abstract
Location information transmission apparatus for exchanging
information about the on-road location on a digital map,
characterized in that apparatus at an information provider
comprises a location information converter for converting transmit
on-road location information to road shape data including the
on-road location consisting of a string of coordinates representing
the road shape of a road section having a length that depends on
the situation and relative data indicating the on-road location in
the road section, and that apparatus at a party receiving the
on-road location information comprises a shape matching section for
performing shape matching by using the road shape data, identifying
the road section on a digital map and identifying the on-road
location in the road section by using the relative data. This makes
it possible to correctly exchange information about the location on
a digital map without defining node numbers or link numbers on a
road network.
Inventors: |
Adachi, Shinya;
(Yokohama-shi, JP) ; Miyama, Satoko;
(Chigasaki-shi, JP) |
Correspondence
Address: |
PEARNE & GORDON LLP
1801 EAST 9TH STREET
SUITE 1200
CLEVELAND
OH
44114-3108
US
|
Assignee: |
Matsushita Electric Industrial Co.,
Ltd.
|
Family ID: |
33297761 |
Appl. No.: |
10/075208 |
Filed: |
February 14, 2002 |
Current U.S.
Class: |
701/532 ;
340/990; 340/995.17 |
Current CPC
Class: |
G08G 1/09675 20130101;
G08G 1/096775 20130101; G09B 29/106 20130101; G01C 21/30 20130101;
G08G 1/096716 20130101 |
Class at
Publication: |
701/208 ;
340/990; 340/995.17 |
International
Class: |
G01C 021/32 |
Claims
1. A location information transmission method for reporting on-road
location on a digital map, characterized in that an information
provider transmits on-road location information by using road shape
data including said on-road location consisting of a string of
coordinates representing the road shape of a road section and
relative data indicating said on-road location in said road
section; and that a party receiving said on-road location
information performs shape matching using said road shape data to
identify said road section on the digital map and uses said
relative data to identify the on-road location in said road
section.
2. A location information transmission according to claim 1,
characterized in that said method uses a string of coordinates
arranging latitude/longitude data of the raod point per
predetermined distance interval as a string of coordinates
representing said road shape.
3. A location information transmission method according to claim 1,
characterized in that said method uses distance data from a
specific point in the road section as said relative data.
4. Location information transmission apparatus for exchanging
information about the on-road location on a digital map,
characterized in that apparatus at an information provider
comprises a location information converter for converting transmit
on-road location information to road shape data including said
on-road location consisting of a string of coordinates representing
the road shape of a road section and relative data indicating said
on-road location in said road section; and that apparatus at a
party receiving the on-road location information comprises a shape
matching section for performing shape matching by using said road
shape data, identifying said road section on a digital map and
identifying the on-road location in the road section by using said
relative data.
5. Location information transmission apparatus according to claim
4, characterized in that said apparatus uses a string of
coordinates arranging latitude/longitude data of the road point per
predetermined distance interval as a string of coordinates
representing said road shape.
6. Location information transmission apparatus according to claim
4, characterized in that said apparatus uses distance data from a
specific point in said road section as said relative data.
7. A traffic information provision/reception system, characterized
in that said system comprises location information transmission
apparatus according to claim 4.
8. A traffic information provision/reception system according to
claim 7, characterized in that said information provider is a
center for collecting traffic information in the area and that said
party receiving the on-road location information is a center for
collecting traffic information in other areas.
9. A traffic information provision/reception system according to
claim 7, characterized in that said information provider is an
infrastructure for providing traffic information and that said
party receiving the on-road location information is a car-mounted
navigation apparatus.
10. A location information transmission method for reporting
on-road location on a digital map, characterized in that an
information provider transmits on-road location information by
using road shape data including said on-road location consisting of
a string of coordinates representing the road shape of a road
section and that a party receiving said on-road location
information performs shape matching using said road shape data to
identify said road section on the digital map.
11. The location information transmission method according to claim
10, characterized in that said method uses a string of coordinates
arranging latitude/longitude data of the road point per
predetermined distance interval as a string of coordinates
representing said road shape.
12. A location information transmission apparatus for exchanging
information about the on-road location on a digital map,
characterized in that: an apparatus at an information provider
comprises a location information converter for converting transmit
on-road location information to road shape data including said on
road location consisting of a string of coordinates representing
the road shape of a road section; and an apparatus at a party
receiving the on-road location information comprises a digital map
and shape matching section for performing shape matching by using
said road shape data and identifying said road section of the
digital map.
13. The location information transmission apparatus according to
claim 12, characterized in that said apparatus uses a string of
coordinates arranging latitude/longitude data of the road point per
determined distance interval as a string of coordinates
representing said road shape.
14. A traffic information provision/reception system, characterized
in that said system comprises location information transmission
apparatus according to claim 12.
15. The traffic information provision/reception system according to
claim 14, characterized in that said information provider is a
center for collecting traffic information in the area and that said
party receiving the on-road location information is a center for
collecting traffic information in other areas.
16. The traffic information provision/reception system according to
claim 14, characterized in that said information provider is an
infrastructure for providing traffic information and that said
party receiving the on-road location information is a car-mounted
navigation apparatus.
17. A receiving device for receiving on-road location information
on a digital map from a device of an information provision side,
said receiving device comprising: a receiver for receiving road
shape data including said on-road location consisting of a string
of coordinates representing the road shape of a road section, from
the device of an information provision side; a digital map; and a
shape matching section for performing shape matching by using said
road shape data and identifying said road section on the digital
map.
18. An information provision apparatus for providing on-road
location information on a digital map by using a location
information transmission method according to claim 10, said
information provision apparatus comprising: a location information
converter for converting transmission on-road location information
to a road shape data including said on-road location consisting of
a string of coordinates representing the road shape of a road
section.
19. A location information transmission method for reporting
location information on a digital map, characterized in that: an
information provider transmits location information using a shape
data including a coordinate string; and a party of receiving side
identify said location using said shape data.
20. The location information transmission method according to claim
19, wherein said coordinate string represents a geometrically
pattern on a digital map.
21. The location information transmission method according to claim
19 or 20, wherein said shape data includes a coordinate string
indicating a region including a position on which an event
occurs.
22. The location information transmission method according to claim
19 or 20, wherein said shape data includes a coordinate string
indicating a border of a region in which an event occurs.
23. The location information transmission method according to claim
19 or 20, wherein said shape data includes a coordinate string
indicating points at predetermined intervals.
24. The location information transmission method according to claim
19 or 20, wherein content of said shape data is changeable in
accordance with a situation of a region indicated by said shape
data.
25. The location information transmission method according to claim
19 or 20, wherein said party of receiving side implements shape
matching using said shape data in order to identify the
location.
26. A location information transmission apparatus for exchanging
location information on a digital map, characterized in that: an
apparatus at an information provider includes a location
information converter which converts a location information to be
transmitted to a shape data having a coordinate string; and an
apparatus at receiving side identifies said location using said
shape data.
27. The location information transmission apparatus according to
claim 26, wherein said shape data includes a coordinate string
indicating a region including a position on which an event
occurs.
28. The location information transmission apparatus according to
claim 26, wherein said shape data includes a coordinate string
indicating a border of a region in which an event occurs.
29. The location information transmission apparatus according to
claim 26, wherein said shape data includes a coordinate string
indicating points at predetermined intervals.
30. The location information transmission apparatus according to
claim 26, wherein content of said shape data is changeable in
accordance with a situation of a region indicated by said shape
data.
31. The location information transmission apparatus according to
claim 26, wherein said apparatus of receiving side implements shape
matching using said shape data in order to identify the
location.
32. A system for providing and/or receiving location information on
a digital map, comprising the location information transmission
apparatus according to any one of claims 26 to 31.
33. The system according to claim 32, wherein said apparatus at an
information provider is a center for collecting traffic information
in a first area, and wherein said apparatus of receiving side is a
center for collecting traffic information in a second area.
34. The system according to claim 32, wherein said apparatus at an
information provider is an infrastructure for providing traffic
information, and wherein said apparatus of receiving side is a
car-mounted navigation apparatus.
35. A receiving device for receiving location information on a
digital map, comprising: a receiving section for receiving shape
data including a coordinate string from an apparatus at an
information provider; a digital map; and location identification
section for identifying the location on said digital map using said
shape data.
36. The receiving device according to claim 35, wherein said
location identification section implements shape matching in order
to identify the location.
37. An information provision apparatus for providing location
information on a digital map, by using the method according to any
one of claims 19 to 25, said apparatus comprising: a location
information converter for converting a location information to be
transmitted to said shape data; and a transmission section for
transmitting said shape data.
38. An information transmission method for transmitting location
information to a device having a digital map, characterized in
that: said location information includes a shape data having a
coordinate string.
39. The information transmission method according to claim 38,
wherein coordinates included in said coordinate string are absolute
coordinates.
40. The information transmission method according to claim 38,
wherein a part of coordinates included in said coordinate string is
relative coordinate.
41. The information transmission method according to any one of
claims 38 to 40, wherein said coordinate string is a coordinate
chain.
42. A coding method for cording an object when information
regarding said object on a traffic rout network is transmitted
between an information provider and a party of receiving side,
characterized in that: said object includes at least a coordinate
string; said coordinate string includes a coordinate on a road,
wherein at least a part of said road is included in a digital map
data of said party of receiving side, and coordinates indicating a
shape whose location is capable of being identified at said party
of receiving side.
43. The location information transmission method according to claim
21 or 22, wherein said information provider transmits information
indicating a type and level of said event, adding to said shape
data.
44. The location information transmission apparatus according to
claim 27 or 28, wherein said apparatus at an information provider
transmits information indicating a type and level of said event,
adding to said shape data.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an information transmission
method for transmitting location information such as traffic jams
and accidents for example in a traffic information provision system
and apparatus for exchanging location information using the method,
and in particular to such a method and apparatus that can correctly
report a location on a digital map.
[0003] 2. Description of the Related Art
[0004] In recent years, the number of vehicles that have
car-mounted navigation apparatus has been increasing rapidly The
car-mounted navigation system has a digital map database and is
capable of displaying the map around the vehicle on a screen based
on the latitude/longitude data received by a GPS receiver as well
as displaying the travel locus and the result of search for a route
to the destination on the map.
[0005] In Japan, digital map databases are prepared by several
companies. The problem is that map data contains errors inherent in
the reduced-scale map. The errors depend on individual digital
maps. Some of the maps on the market drawn on the scale of 1:25000
contain errors of about 50 meters depending on the location.
[0006] Latitude/Longitude data obtained from a GPS receiver may
contain errors of several tens of meters.
[0007] Some models of car-mounted navigation apparatus on the
market receives traffic jam information and accident information
from a traffic information provision system and displays the
traffic jam and accident locations on the map or performs route
search using such information as additional search conditions.
[0008] In a related art traffic information provision system, as
shown in FIG. 7, traffic information is provided from a traffic
information collecting center 71 that has local jurisdiction over
an area to an information delivery center 72. Traffic information
edited for each transmission medium including FM broadcasts, road
beacons and cell phones is transmitted via respective media.
[0009] The traffic information collecting center 71 exchanges
traffic information with a traffic information collecting center 78
in other areas to collect traffic information in a wide service
area including the peripheral areas.
[0010] In the traffic information, for example, in case
latitude/longitude data on the location is presented alone in order
to report a traffic jam location or accident location, various
errors are contained depending on the kind of digital map database
of the car-mounted navigation apparatus as mentioned earlier. Thus,
different accident locations on the road could be recognized by the
car-mounted navigation apparatus retaining a digital map database
from Company A and the car-mounted navigation apparatus retaining a
digital map database from Company B.
[0011] In order to alleviate incorrect information transmission, as
shown in FIG. 8A, crossings a and b on a road network are assumed
as nodes, and a road c connecting the nodes as a link. Each node is
assigned a node number uniquely representing the node (a=1111,
b=3333). Each link is assigned a link number uniquely representing
the link (c=11113333) In the digital map database of each company,
the node numbers and link numbers thus assigned are stored, in
correspondence with each crossing and road.
[0012] In traffic information provision service, a point on the
road is represented by first specifying a link number then the
distance in meters from the start of the link. For example, a
display "Location 200 meters from the start of the road with link
number=11113333" allows the user to obtain the location P on the
same road by tracing the road with link number=11113333 as far as
200 meters from the node with node number 1111, irrespective of
what digital map data is used by the car-mounted navigation system
in question.
[0013] Node numbers and link numbers defined on a road network must
be changed to new numbers in case a road d is constructed or a road
is modified as shown in FIG. 8B. Such modifications to node numbers
and link numbers require updating of digital map data from each
company.
[0014] Construction of or modification to a road continue into the
future. As long as on-road location representation is made using
node numbers and link numbers, maintenance of digital map databases
is permanently accompanied by huge work load and resulting
costs.
[0015] The information delivery center must send information that
complies with past node numbers and link numbers for a
predetermined period, for example three to five years, as well as
the information of the latest year, in order to support navigation
systems sold in the past. This causes huge maintenance
workload.
SUMMARY OF THE INVENTION
[0016] The invention solves such related art problems and aims at
providing a location information transmission method that can
transmit a location on a digital map without excessive maintenance
workload and apparatus for implementing the method.
[0017] In a location information transmission method according to
the invention, an information provider transmits on-road location
information by using road shape data consisting of a string of
coordinates representing the road shape of a road section having a
length that depends on the situation and relative data indicating
the on-road location in the road section. A party receiving the
on-road location information performs shape matching to identify
the road section on the digital map and uses relative data to
identify the on-road location in this road section.
[0018] In location information transmission apparatus according to
the invention, apparatus at an information provider comprises a
location information converter for converting transmit on-road
location information to road shape data consisting of a string of
coordinates representing the road shape of a road section having a
length that depends on the situation and relative data indicating
the on-road location in the road section Apparatus at a party that
receives the on-road location information comprises a shape
matching section for performing shape matching by using the
received road shape data, identifying the road section on a digital
map and identifying the on-road location in the road section by
using the relative data.
[0019] Thus, it is possible to correctly transmit a location on a
digital map as well as the travel direction of the vehicle without
defining node numbers or link numbers on a road network
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a block diagram showing a configuration of
location information transmission apparatus in the first embodiment
of the invention.
[0021] FIG. 2 is a flowchart showing the operation of location
information transmission apparatus in the first embodiment of the
invention.
[0022] FIG. 3 is an explanatory drawing illustrating road shape
data and distance data constituting the road location
information.
[0023] FIG. 4 is an explanatory drawing showing an example of shape
matching.
[0024] FIG. 5 is a block diagram showing a configuration of
location information transmission apparatus in the second
embodiment of the invention.
[0025] FIG. 6 is a block diagram showing another configuration of
location information transmission apparatus in the second
embodiment,
[0026] FIG. 7 is an explanatory drawing showing a traffic
information provision system.
[0027] FIG. 8A is an explanatory drawing of node numbers and link
numbers.
[0028] FIG. 8B is an explanatory drawing of modifications to node
numbers and link numbers made when a new road is constructed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] The first aspect of the invention is a location information
transmission method for transmitting on-road location on a digital
map, characterized in that an information provider transmits
on-road location information by using road shape data including the
on-road location information consisting of a string of coordinates
representing the road shape of a road section having a length that
depends on the situation and relative data indicating the on-road
location in the road section and that a party receiving the on-road
location information performs shape matching to identify the road
section on the digital map and uses the relative data to identify
the on-road location in the road section. This makes it possible to
correctly report a location on a digital map without defining node
numbers or link numbers on a road network.
[0030] The second aspect of the invention uses a string of
coordinates arranging latitude/longitude data of the road point per
predetermined distance interval as a string of coordinates
representing the road shape. A party receiving the on-road location
information uses the latitude/longitude data of each point to
perform shape matching thus identifying the road section having the
same road shape.
[0031] The third aspect of the invention uses distance data from a
specific point in the road section as the relative data. A party
receiving the on-road location information uses the distance data
to identify the on-road location after identifying the road
section.
[0032] The fourth aspect of the invention is location information
transmission apparatus for exchanging information about the on-road
location on a digital map, characterized in that apparatus at an
information provider comprises a location information converter for
converting transmit on-road location information to road shape data
including the on-road location consisting of a string of
coordinates representing the road shape of a road section having a
length that depends on the situation and relative data indicating
the on-road location in the road section, and that apparatus at a
party receiving the on-road location information comprises a shape
matching section for performing shape matching by using the road
shape data, identifying the road section on a digital map and
identifying the on-road location in the road section by using the
relative data. This makes it possible to correctly exchange
information about the location on a digital map without defining
node numbers or link numbers on a road network.
[0033] The fifth aspect of the invention uses a string of
coordinates arranging latitude/longitude data of the road point per
predetermined distance interval as a string of coordinates
representing the road shape. The shape matching section of the
apparatus at a party receiving the on-road location information
uses the latitude/longitude data of each road point to perform
shape matching thus identifying the road section having the same
road shape.
[0034] The sixth aspect of the invention uses distance data from a
specific point in the road section as the relative data. The shape
matching section of the apparatus at a party receiving the on-road
location information uses the distance data to identify the on-road
location after identifying the road section.
[0035] The seventh aspect of the invention is a traffic information
provision/reception system to which location information
transmission apparatus according to the fourth aspect of the
invention is applied. This makes it possible to correctly report
the location on a digital map without using node numbers or link
numbers.
[0036] The eighth aspect of the invention is characterized in that
apparatus at the information provider is a center for collecting
traffic information in the area and that apparatus at the party
receiving the on-road location information is a center for
collecting traffic information in other areas. This makes it
possible to use the location information transmission method for
exchange of traffic information between centers.
[0037] The ninth aspect of the invention is characterized in that
apparatus at the information provider is an infrastructure for
providing traffic information and that apparatus at the party
receiving the on-road location information is a car-mounted
navigation apparatus. This makes it possible to use the location
information transmission method for information provision to
car-mounted navigation apparatus.
[0038] Embodiments of the invention will be described referring to
the drawings.
[0039] (First Embodiment)
[0040] In the first embodiment, a location information transmission
method according to the invention will be described taking as an
example the case where traffic information is exchanged between
traffic information collecting centers in FIG. 7
[0041] The traffic information collecting center A, as shown in
9.
[0042] FIG. 1, comprises an event information input section 1 for
inputting event information such as traffic accidents and traffic
jams, a location information converter 2 for generating location
information representing the event location, a location information
transmitter 3 for transmitting the generated location information,
a location information receiver 6 for receiving the location
information, a shape matching section 5 for performing shape
matching and identifying the event location from the location
information, a digital map display section 4 for displaying the
event location on a map, and a digital map database 7. The traffic
information collecting center B has the same configuration as the
traffic information collecting center A.
[0043] Operation flow of the traffic information collecting center
is shown in FIG. 2.
[0044] (Step 1:) When an event such as a traffic accident or a
traffic jam takes place, (Step 2:) The event details and the event
location information are input to the event information input
section 1 of the traffic information collecting center. For
example, when information indicating occurrence of a traffic jam is
input to a vehicle detector installed on the road, (Step 3:) the
location information converter 2 generates road shape data
including traffic jam location consisting of a string of
coordinates representing the road shape of a road section having a
predetermined length and distance data indicating the distance from
the start point of the road section to the traffic jam location, in
order to report the traffic jam information to the traffic
information collecting center B.
[0045] FIG. 3 is a schematic view showing the location information
generated by the location information converter 2. In case a
traffic jam has occurred in the section A to B on the road, the
road shape of the road including the section is represented in a
string of coordinates consisting of 601 points in 5-meter
intervals, P.sub.0 (x.sub.0, y.sub.0), P.sub.1(x.sub.1, y.sub.1), .
. . , p.sub.600(x.sub.600, y.sub.600). Here, x.sub.k and y.sub.k
are latitude and longitude data, respectively, of the on-road point
p.sub.k acquired from the digital database 7. Further, the distance
l.sub.1 from the point P.sub.0(x.sub.0, y.sub.0) to the traffic jam
start point A and the distance l.sub.2 from the point
P.sub.0(x.sub.0, y.sub.0) to the traffic jam end point B are
obtained and the road shape data: (x.sub.0, y.sub.0) (x.sub.1,
y.sub.1) . . . (x.sub.600, y.sub.600) and traffic jam distance
data; l.sub.1 to 1.sub.2 L are generated as location
information.
[0046] Rank information indicating the degree of traffic jam and
information indicating the type of a digital map database used are
added to the location information to create transmit information,
and (Step 4:) the location information transmitter 3 transmits the
information to the traffic information collecting center B.
[0047] (Step 5:) In the traffic information collecting center,
receiving the information at the location information receiver 6,
(Step 6:) the shape matching section 5 performs shape matching of
map data in the digital map database 7 and the string of
coordinates indicating the road shape to identify the road section
on the digital map, then identifies the traffic am section on the
digital map based on the distance data from the start point of the
road section.
[0048] FIG. 4 shows an example of shape matching
[0049] Roads Q and R included within the error range around the
P.sub.0(x.sub.0, y.sub.0) point of map data read from the digital
map database 7 are selected as candidates.
[0050] Then, locations Q.sub.0, R.sub.0 on each candidate road
closest to P.sub.0 (x.sub.0, y.sub.0) are obtained and distance
P.sub.0-Q.sub.0 and distance P.sub.0-R.sub.0 are calculated.
[0051] This operation is carried out for each point P.sub.0
(x.sub.0, y.sub.0), P.sub.1(x.sub.0, y.sub.1), p.sub.600(x.sub.000,
y.sub.600) and the road section where the smmation value of the
root mean square of the distances from each point P.sub.0, P.sub.1,
. . . , p.sub.600 is smallest is obtained.
[0052] Then the section l.sub.1-l.sub.2 m from the start point of
the road section is identified as a traffic jam section.
[0053] (Step 7:) The digital map display section 4 reads data from
the digital map database 7 and displays a map, then paints the
colors corresponding to the traffic jam levels in the traffic jam
section obtained by the shape matching section 5.
[0054] In this way, the party receiving information can perform
shape matching and identify the road section having the road shape
without defining node numbers or link numbers, when the information
provider represents the road shape using a string of
coordinates.
[0055] While the interval of points used to indicate the shape of
the road section is 5 meters and the number of points is 601 in
this embodiment, the interval and the number are not intended to
limit the invention.
[0056] While latitude and longitude data is used as coordinate data
in a string of coordinates in this embodiment, other coordinate
data may be used so long as the data can be shared by the
information provider and the information receiver.
[0057] By adding effective auxiliary information to the transmit
location information, it is possible to enhance the efficiency of
shape matching at the receiving party.
[0058] As a shape matching algorithm, a method other than the
illustrated least square method may be used.
[0059] (Second Embodiment)
[0060] In the second embodiment, transmission of location
information between the infrastructure of the traffic information
provision system (information provider) and the car-mounted
navigation apparatus will be described.
[0061] Here, infrastructure refers to such social infrastructures
as broadcasting stations, traffic signs, traffic signal lights or
traffic monitoring cameras and so on. The social infrastructures
may involve centers to control the forementioned stations, signs or
other elements that are parts of the infrastructure.
[0062] FIG. 5 shows an infrastructure 51 that provides information
and car-mounted navigation apparatus 61 that receives
information.
[0063] The infrastructure 51 comprises an event information input
section 52 for inputting event information, a location information
converter 53 for generating location information representing the
event location, a location information transmitter 54 for
transmitting the generated location information, a digital map
display section 55, and a digital map database 56.
[0064] The car-mounted navigation apparatus 61 comprises a location
information receiver 62 for receiving location information, a shape
matching section 63 for performing shape matching and identifying
the event location from the location information, a digital map
display section 64 for displaying the event location on a map, and
a digital map database 65.
[0065] Operation of the infrastructure is the same as the operation
of step 1 through step 4 of FIG. 2. Operation of the car-mounted
navigation apparatus is the same as the operation of step 5 through
step 7 of FIG. 2.
[0066] In the traffic information provision system, the
infrastructure provides information including the string of
coordinates of the road section of a predetermined length including
the event location and the information on the event location that
uses the road section as a reference, via FM broadcasts and beacons
The car-mounted navigation apparatus identities the road section
from the string of coordinates and identifies the event location by
using the road section as a reference. Thus, it is possible to
correctly report the location on a digital map without defining
node numbers or link numbers.
[0067] FIG. 6 shows a case where the car-Mounted navigation
apparatus comprises an event information input section, a location
information converter, a location information transmitter, a
location information receiver, a shape matching section, a digital
map display section, and a digital map database. The car-mounted
navigation apparatus can transmit the accident location to the
infrastructure if an accident takes place.
[0068] In this practice, the car-mounted navigation apparatus
acquires from the digital map database coordinate data of a
plurality of locations in the road section of a predetermined
length including the accident location. Then the car-mounted
navigation apparatus transmits the coordinate data and information
on the event location using the road section as a reference. The
center receives the information and performs shape matching to
identify the road section from the road shape, then identifies the
accident location.
[0069] As understood from the foregoing description, a location
information transmission method and apparatus can correctly report
the location on a digital map to a distant party without using node
numbers or link numbers on a road network.
[0070] With this method, it is possible to substantially reduce
workload and costs for maintenance of digital map databases thus
reducing the socials costs for maintaining the traffic information
provision system.
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