JP2002328027A - Digital map location information transmission method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a method of transmitting position information of a digital map which can efficiently transmit a vector shape on a digital map and reduce a processing load of map matching. SOLUTION: To transmit an event position on a digital map, data representing a vector shape including the event position on the digital map is represented by a node sequence, and data representing an event position on the vector shape is represented by relative position information. In the position information transmission method in which the receiving side performs map matching between the data of its own digital map and the received data to specify the event position on its own digital map, the transmitting side includes The positions of a plurality of successive nodes are transmitted by expressing the distance Li from the previous node and the relative azimuth Θj, respectively. The receiving side sets the next candidate point by moving forward by the distance from the candidate point on the vector shape, and sets the candidate from the difference between the intersection angle corresponding to the relative direction of the straight line connecting the preceding and following candidate points and the relative direction. Evaluate points.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transmitting position information of a digital map, and more particularly, to a method for efficiently specifying a position on a digital map on a receiving side.

[0002]

2. Description of the Related Art In recent years, vehicles equipped with on-vehicle navigation devices have been rapidly increasing. Navigation onboard equipment
Maintains a digital map database, displays traffic congestion and accident locations on a map based on traffic congestion information and accident information provided by a traffic information center, etc., and conducts a route search with such information added as conditions. .

[0003] Digital map databases are created by several companies in Japan. However, due to differences in base maps and digitizing technology, this map data contains errors, and the errors differ depending on the digital map of each company. ing.

For example, when an accident location is reported in traffic information or the like, if the longitude / latitude data of the location is presented alone, the in-vehicle device may determine the location on a different road depending on the type of digital map database held. There is a possibility that it will be identified as a position.

In order to improve the inaccuracy of information transmission, node numbers are conventionally defined for nodes such as intersections existing in a road network, and link numbers are defined for links representing roads between nodes. In the digital map database of each company, each intersection or road is stored in association with the node number and the link number. In the traffic information, the road is specified by the link number, and the road is expressed by a number of meters from the head. The point above is displayed.

However, it is necessary to replace the node numbers and link numbers defined in the road network with new numbers in accordance with the construction and change of roads. When the node numbers and link numbers are changed, the digital map of each company is changed. Data must also be updated. Therefore, the method of transmitting the position information of the digital map using the node number or the link number requires a large social cost for the maintenance.

In order to improve such a point, the inventors of the present invention have disclosed in Japanese Patent Application Nos. 11-214068 and 11-2104.
No. 42166, when an information provider informs a road position where an event such as traffic congestion or an accident has occurred, “road shape data” including a coordinate sequence indicating a road shape of a road section of a predetermined length including the event position, The "event position data" representing the event position is transmitted to the receiving side based on the relative position within the road section represented by the road shape data, and on the side receiving such information, map matching is performed using the road shape data. To identify road sections on your digital map,
We propose a method to specify the event occurrence position in this road section using the event position data.

In this system, as shown in FIG. 12, for example, when traffic congestion occurs in sections A and B on a road, the information providing side transmits information to road sections P _{1 to} P _n including sections A and B. Longitude / latitude data P of a node and an interpolation point (the vertex of a polygonal line approximating a curve of a road. In this specification, unless otherwise specified, the node is referred to as a "node" including the interpolation point).
₁ (x ₁ , y ₁ ), P ₂ (x ₂ , y ₂ ), ‥, P _n (x _n ,
convey y _n) on the reception side as "road shape data", also this and the reference point in the road section (section start point, by specifying near an intersection node) to the event generation position, the point from which A, B Is transmitted to the receiving side as "event position data".

As shown in FIG. 13, the receiving side receives step 1: road shape data, relative position of event occurrence, and event content data. Step 2: performs map matching using the road shape data. Identify the target road section. Step 3: The event position is determined on the target road section using the relative distance data indicating the relative position at which the event has occurred. Step 4: The event position is displayed on the screen over the map.

[0010]

However, this method is
There is a problem that the amount of transmission data increases, and the receiving side also has a large processing load for the calculation of the map matching, which leaves room for improvement.

The present invention solves such a problem, and provides a digital map position information transmission method capable of efficiently transmitting a vector shape on a digital map and reducing the processing load of map matching. It is intended to be.

[0012]

Therefore, according to the present invention, in order to transmit an event position on a digital map, the transmitting side transmits data representing a vector shape including the event position on the digital map by a node sequence, The receiving side transmits data representing the event position on the vector shape as relative position information, and the receiving side performs map matching between the data of the own digital map and the received data to perform the previous matching on the digital map. In the method for transmitting position information of a digital map for specifying the position of an event, the transmitting side transmits the position of a plurality of continuous nodes included in the node sequence by expressing each of the positions by a distance from a previous node and a relative direction. Like that.

On the receiving side receiving this data, it is possible to set the next candidate point by advancing by the distance from the candidate point on the vector shape, and to correspond to the relative azimuth of a straight line connecting the preceding and following candidate points. The candidate point can be evaluated from the difference between the intersection angle and the relative orientation. Therefore, the processing load of the map matching is reduced.

[0014]

FIG. 2 shows a position information transmitting / receiving apparatus 10 for exchanging traffic information with another apparatus 20 as an example of an apparatus for implementing the position information transmitting method of the present invention.

The apparatus 10 includes a position information receiving section 11 for receiving information including road shape data and event position data from a position information transmitting section 21 of another apparatus 20, a digital map database 14 for storing digital map data, and A map matching unit 12 that performs map matching using road shape data and event position data to specify an event position on a digital map, a digital map display unit 13 that superimposes and displays the event position on a map, An event input unit 15 for inputting the generated event information, a position information conversion unit 16 for generating position information including road shape data and event position data for transmitting the event information, and another device for transmitting the generated position information to another device. And a position information transmitting unit 17 for transmitting to the 20 position information receiving units 22.

(First Embodiment) In the first embodiment,
The operation of the transmitting side of the position information transmitting / receiving device 10 will be described.

FIG. 3 shows a processing procedure of the position information converter 16 for generating transmission data. This is a procedure executed by the computer of the position information transmitting / receiving device 10 according to a program in order to realize the function of the position information conversion unit 16. Step 1: The position information conversion unit 16 receives, from the event information input unit 15, traffic information notifying the event occurrence position such as a traffic accident or traffic congestion and the contents of the event. A predetermined section including the event occurrence position on the road where is generated is selected as a target road section for transmitting the road shape.
At this time, it is desirable to select, as an end point of the target road section, a point where erroneous matching hardly occurs.

Step 3: Next, the coordinate data (latitude / longitude data) of the node included in the target road section is converted into data of “distance and relative azimuth from the previous node”. In this specification, expressing a position by “distance and relative azimuth from the previous node” is referred to as “curvature function”. FIG. 4 shows a method of calculating the distance (L _j ) from the previous node and the relative azimuth (= azimuth displacement difference: Θ _j ) in order to convert the xy coordinate expression into a curvature function expression. FIG.
Indicates a coordinate sequence (b) when the shape (a) of the target road section in the original map data is expressed by a curvature function. In addition,
As shown in FIG. 1, from the original map data of the target road section,
A node that can reproduce the shape of the target road section with a smaller number may be resampled, and only the resampled node may be represented by a curvature function to reduce the amount of transmission data.

Step 4: Next, the traffic information is represented by a relative position on the shape data of the target road section represented by the curvature function. Step 5: The traffic information and the shape of the target road section represented by the curvature function The data is transmitted from the position information transmitting unit 17.

FIG. 5A shows an example of transmission data for transmitting a shape vector of a target road section. FIG. 5 (a)
Is an example in which interpolation points between nodes are represented by a curvature function. The start node p1 includes absolute coordinates (longitude and latitude) representing the position and data of the absolute direction (ω in FIG. 4) in the intercept direction. The position of the interpolation point is represented by the distance (L _j ) from the previous node (or previous interpolation point) and the azimuth difference (relative azimuth Θ _j ) from the previous node (or previous interpolation point).
FIG. 5B shows an example in which all nodes are represented by a curvature function.

FIG. 5C shows transmission data of traffic information transmitted together with the shape vector data of FIG. 5A or FIG. 5B, and a reference point for indicating an event occurrence position. (If this is a node in the target road section,
The information may include a node other than the start point, a relative distance from the reference point, and an event event number indicating the content of the event.

(Second Embodiment) In a second embodiment,
The operation of the receiving side of the position information transmitting / receiving device 10 that has received the shape vector data and the traffic information will be described.

FIG. 6 shows an operation procedure on the receiving side.
This is a procedure executed by the computer of the position information transmitting / receiving device 10 according to a program to realize the function of the map matching unit 12. Step 20: When the position information receiving unit 11 receives the shape vector data of the target road section and the traffic information including the relative position and the event content in the target road section, Step 21: The map matching unit 12 Map matching and digital map database
Identify the target road section on your digital map stored in 14.

FIG. 7 shows the procedure of this map matching.
FIG. 8 schematically shows the state. Step 31: The first (j = 1) of the shape vector data
Focusing on the starting node, Step 32: Starting node p₁Expressed in latitude and longitude data
Coordinates (if there is intercept direction information, add the direction information
), On m nearby roads within approximately 200m
Set m candidate points. Step 33: 1st (i = 1) candidate point P₁≡_iFocus on
Step 34: Start node p₁Candidate point P from position₁≡₁Until
Distance D₁Is calculated. Step 35, Step 36: Another candidate point P₁≡_iabout
Is also the start node p ₁Distance D from_iIs calculated.

[0025] Step 37: Next, as shown in FIG. 9, the current candidate point P _j ≡ _i of each road, along the road, the shape vector data p _j → p _{j + 1} between the distance L _j Advanced point P
asked the _{j + 1, i,} step _{38: P j-1, i} → P j, the straight line connecting the _i and P _{j, i} →
The difference | Δθ _j , _i | between the angle θ _j , _i formed by the straight line connecting P _{j + 1} , _i and the relative orientation Θ _{j of} p _j represented by the shape vector data is calculated (Equation 1). To calculate the evaluation value ε _j , _i . ε _j , _i = α × D _i + Σ (β × | Δθ _j , _i |) (Equation 1) (Σ is added from j = 1 to j) α: predetermined coefficient β: predetermined coefficient Step 39: Next, the candidate point P _j , _i is moved to the candidate point P _{j + 1} , _i .

Step 40, Step 41: Steps 37 to 39
Is performed for all candidate points. Step 42, Step 43: The processing of Steps 37 to 41 is executed for all nodes included in the shape vector data. When proceeding with this process, if there is a branch (intersection, etc.) on the receiving map data,
Once the angles θ _j , _i are obtained for all connecting roads, | Δ
The connection road with the smallest θ _j , _i | is adopted and the process proceeds to the next. When the processing for all the nodes included in the shape vector data is completed, Step 44: The candidate having the smallest evaluation value ε _i is set as the target road.

When the target road section is obtained on the own digital map, the procedure returns to the procedure of FIG. 6, and step 22: The event point on the target road section is determined based on the relative position data included in the traffic information. Step 23: The event position is displayed on the screen of the digital map display section 13 so as to overlap the map.

As described above, when map matching is performed using the shape vector data represented by the curvature function,
"Distance L from previous node included in shape vector data
_i ”to easily find the next candidate point,
Further, the evaluation value can be calculated by directly using the “relative azimuth” included in the shape vector data. for that reason,
The processing load of map matching on the receiving side is reduced.

(Third Embodiment) In the third embodiment,
A matching process on the receiving side to which the successive matching method is applied will be described.

On the receiving side, as in the second embodiment,
The shape vector data of the target road section displayed by the curvature function and the traffic information including the relative position and the event content in the target road section are received.

FIG. 10 shows the processing procedure of the map matching unit 12 in this case. Step 51: Calculate the event occurrence position in the target road section based on the shape vector data of the target road section and the relative position data of the event occurrence position included in the traffic information, and store the event point in the shape vector data as a node. Added as equivalent points. The number of nodes including event points is m. FIG. 11 shows a state where the event point (X) is included in the shape vector data. The procedure from step 52 to step 62 is
This is the same as the procedure from step 31 to step 41 of the second embodiment (FIG. 7).

However, the evaluation value calculated in step 59 is obtained by the following (Equation 2). _{ε j, i = α × D} i + Σ (β × | Δθ j, i |) + σ ( Equation 2) (sigma in addition j = 1 through j) D _i: length of start coordinates and the starting candidate point alpha : Predetermined coefficient β: Predetermined coefficient σ: 0 when the candidate point is the candidate point (map matching point) with the highest evaluation value among the plurality of candidate points for the previous node, otherwise The penalty value determined in advance

When the processing of steps 58 to 62 is completed for all the candidate points P _j ≡ _i up to the node p _j , step 63: the candidate point having the best evaluation value is adopted as the map matching point. When the candidate point is adopted as the map matching point, when calculating the evaluation value of the next candidate point, (Equation 2)
Is calculated assuming 0 as 0. This σ is added to the evaluation value in order to suppress the map matching point from varying between roads. Step 64: Candidate points P _j adopted as map matching points
≡ If _i is a candidate event point, it is superimposed and displayed as an event point on the map.

In this method, when a map matching point corresponding to a node at an event occurrence position is obtained, the distribution of map matching points on the road and the like up to that point are taken into consideration.
Subsequent matching processing can be saved. Therefore, it is possible to efficiently determine the event occurrence position.

Also, here, the case where the position on the road of the digital map is reported has been described as an example. However, the present invention is not limited to roads, and various shape vectors represented on the digital map, such as rivers and contour lines, may be used. Applicable when communicating the position above.

[0036]

As is clear from the above description, in the position information transmitting method of the present invention, since the shape vector data is represented by the curvature function and transmitted, the map matching processing on the receiving side is reduced. Further, in the method that adopts the concept of the sequential matching, the map matching can be stopped when the event position is specified on the receiving side, and the burden on the receiving side can be further reduced.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing shape vector data transmitted in a position information transmission method according to a first embodiment;

FIG. 2 is a block diagram illustrating a configuration of an apparatus that implements the position information transmission method according to the embodiment;

FIG. 3 is a flowchart showing a processing procedure on the transmission side for implementing the position information transmission method according to the first embodiment;

FIG. 4 is a view for explaining a method of converting into a curvature function expression according to the first embodiment;

FIG. 5 is a diagram showing transmission data in the position information transmission method according to the first embodiment;

FIG. 6 is a flowchart showing a processing procedure on the receiving side that performs map matching according to the second embodiment;

FIG. 7 is a flowchart showing the procedure of map matching in the second embodiment;

FIG. 8 is a diagram schematically showing a map matching process according to the second embodiment;

FIG. 9 is a diagram showing a method for obtaining a next candidate point in map matching according to the second embodiment;

FIG. 10 is a flowchart showing a map matching procedure according to the third embodiment;

FIG. 11 is a diagram illustrating a map matching method according to a third embodiment;

FIG. 12 is a view for explaining road shape data and event position information;

FIG. 13 is a flowchart showing a receiving-side procedure in a conventional position information transmission method.

[Explanation of symbols]

 10, 20 Position information transmitting / receiving device 11, 22 Position information receiving unit 12 Map matching unit 13 Digital map display unit 14 Digital map database 15 Event information input unit 16 Position information conversion unit 17, 21 Position information transmitting unit

Claims (6)

[Claims] 1. A transmitting side, in order to report an event position on a digital map, data representing a vector shape including the event position on the digital map as a node sequence, and the event position on the vector shape. Is transmitted as relative position information, and the receiving side performs map matching between the data of the digital map and the received data to determine the position of the digital map on the digital map. In the information transmitting method, a transmitting side transmits the position of a plurality of continuous nodes included in the node sequence by expressing each of the positions as a distance from a previous node and a relative direction. 2. A receiving side sets, as a next candidate point, a position on a vector shape advanced by the distance from a candidate point for map matching set on a vector shape of the digital map of the receiving side. The position information transmission method according to claim 1, wherein the candidate point is evaluated by an evaluation value including, as an element, a difference between an intersection angle corresponding to the relative azimuth of the straight line connecting the azimuth and the relative azimuth. 3. The receiving side specifies the event position on the vector shape using the received relative position information, and uses the node sequence data including the event position data to specify the event position. The position information transmission method according to claim 1, wherein map matching is performed. 4. The receiving side performs map matching using the received vector shape, specifies a corresponding section on its own digital map, and determines an event position in the specified section using the relative position information. The method according to claim 1, wherein the location information is specified. 5. In order to inform a receiving side of an event position on the digital map, data representing a vector shape including the event position on the digital map by a node sequence, and the event position on the vector shape are represented by: A program of a transmitting device for transmitting data represented by relative position information, the method comprising: selecting, on a computer, a target road section on a digital map including the event position; A step of converting the coordinate data of the node into data of the distance and relative azimuth from the previous node, and setting a reference point from a node in the node train, and setting the event position relative to the reference point. The procedure for converting and executing the program. 6. Receiving data representing a vector shape of the digital map by a node sequence and data representing an event position on the vector shape by relative position information, A program for a receiving apparatus for performing the map matching to specify the event position on the digital map of the own device, comprising: A step of setting the position on the vector shape advanced by the distance of the next node included in the column data as the next candidate point; a step of calculating the intersection angle of a straight line connecting the preceding and following candidate points; Calculating a difference between the relative azimuth included in the data and the corresponding intersection angle; calculating an evaluation value including the difference in an element to evaluate the candidate point Program to be executed and that procedure.