JP2009015739A - Traffic information distribution server, traffic information distribution system, and traffic information distribution method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a traffic information distribution server, a traffic information distribution system, and a traffic information distribution method which distribute intelligible traffic information while reducing a communication amount when distribution is performed to a wide area. <P>SOLUTION: The traffic information distribution server is provided with a traffic information summary part which divides an area into grids, calculates link passage grids of traffic information data, calculates congestion distribution in which length of links included in the respective grids is weighted according to congestion degrees, and calculates smoothed congestion distribution obtained by smoothing the congestion distribution by the adjacent grids. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technology for distributing traffic information to a navigation device connected via a network, and in particular, traffic information for distributing easy-to-understand traffic information while reducing the amount of communication when distributing a wide area. The present invention relates to a distribution server, a traffic information distribution system, and a traffic information distribution method.

  Services such as VICS (Vehicle Information and Communication System) are known as traffic information distribution services. Traffic information is distributed using FM multiplex broadcasting by FM stations, light or radio wave beacons installed on roads, mobile phones, and the like.

  Traffic information by these services is provided in a format associated with a road map of a certain scale level, and is displayed only when the scale of the map displayed on the screen of the navigation device is within the corresponding range. For this reason, there is a problem that the received traffic information cannot be displayed if the map scale is reduced to display a wide area. For example, Patent Document 1 provides a vehicle information display device that enables traffic information received from the outside to be displayed even when displaying a wide area. In this apparatus, the degree of traffic jam is calculated for each map area indicated by the map code, and each map area is displayed in different colors according to the traffic jam degree.

  Further, in the conventional navigation device, the received traffic information is displayed in the same format without distinction depending on the area. In areas where roads are dense, such as the city center, there is a problem that even if traffic information is displayed, the screen is full of arrows, making it difficult to see. For example, Patent Document 2 provides a traffic information display device that allows a driver to intuitively grasp traffic information received from the outside. Similar to Patent Document 1, the degree of congestion is calculated for each divided map area, and is displayed in different colors according to the degree of congestion. However, it is disclosed that the division of the map area is not limited to the lattice shape but may be an arbitrary shape and may be non-uniform. Furthermore, it is disclosed that weighting is performed with an emphasis on the direction of travel when calculating the degree of congestion.

JP 7-21492 A JP-A-10-283588

  As described above, the conventional traffic information service has a problem that the traffic information received in the display of the wide area is not displayed. In addition, in an area where roads are dense such as in the city center, there is a problem that even if traffic information is displayed, the screen is complicated and difficult to see. In the city center, there is also a problem that there is a lot of information on traffic congestion points and accident regulations, and the amount of communication becomes enormous depending on the time of day. Furthermore, if the number of roads on which traffic information is provided increases due to the spread of probe car systems and the like, it is considered that such a problem becomes apparent.

  The present invention has been made in view of such circumstances, and in particular, a traffic information distribution server and a traffic information distribution that distribute easy-to-understand traffic information while reducing the amount of communication when distributing a wide area. It is an object to provide a system and a traffic information distribution method.

  In order to achieve the above object, in the present invention, according to a traffic information request message designating a time and a region, road data corresponding to the region is searched from a map data storage unit, and traffic information at the time corresponding to the road data is retrieved. A traffic information search unit for searching for data, a traffic information summarizing unit for generating traffic distribution data from the road data and the traffic information data at a resolution corresponding to the area, and a response message including the traffic distribution data And a traffic information transmission unit.

  The traffic information summarizing unit divides the area into grids, obtains a link passing grid of the traffic information data, and calculates a traffic congestion distribution in which the lengths of links included in each grid are weighted according to the traffic congestion degree. The method is characterized by calculating a smoothed traffic jam distribution obtained by smoothing a traffic jam distribution with an adjacent grid.

  According to the present invention, since the traffic congestion distribution data is generated with a level of resolution corresponding to the area to be distributed, it is possible to reduce the amount of communication when distributing a wide area. Compared to the case where the traffic distribution is calculated by the navigation device, the memory consumption and calculation load of the navigation device are reduced. In addition, the present invention proposes a method of smoothing not only the traffic congestion distribution of each grid but also adjacent grids. By smoothing, it is possible to catch a point where traffic information is concentrated and to distribute traffic information that is easy to understand.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a traffic information distribution system to which the present invention is applied. The traffic information distribution system includes a navigation device 10 mounted on an automobile and a traffic information distribution server 30 connected to a communication network NW. A plurality of radio base stations 20 are connected to the communication network NW, and the navigation apparatus 10 is connected to the traffic information distribution server 30 via the radio base stations 20.

  The navigation device 10 obtains current location information by using a control unit 100 that controls the entire device, a map data storage unit 101 that stores map display data, and a GPS (Global Positioning System) sensor. Unit 102, input unit 103 that receives input from a user, display unit 104 that displays a user operation screen and a map, wireless base station 20, and wireless for connecting to traffic information server 30 via communication network NW The communication unit 105 is included.

  The control unit 100 includes a processor 106 and a memory 107, and the memory 107 stores a program executed by the processor 106. As a program related to the present invention, an input reception control unit 108 that receives a traffic information request command specifying a region and time from the input unit 103 by a user operation and transmits a traffic information request message to the traffic information distribution server 30; A traffic information display unit 109 that displays traffic distribution data included in the response message received from the information distribution server 30 on the display unit 104 is stored. Further, the traffic information display unit 109 may superimpose map display data retrieved from the map data storage unit 101 on the display of the traffic congestion distribution data. As the map display data, for example, road data in a designated area, character data corresponding to a place name of a traffic jam location, and the like are superimposed.

  The map data storage unit 101 is configured by a relatively large-capacity storage medium such as a DVD (Digital Versatile Disk), a hard disk drive, or a flash memory. The input unit 103 includes a touch panel and operation buttons, and may further include a microphone or the like for voice input. The display unit 104 includes a display screen such as a liquid crystal display, and may further include a speaker or the like for audio output. The memory 111 includes a ROM (Read Only Memory) and a RAM (Random Access Memory). In addition to the execution program, the map display data read from the map data storage unit 101 and the traffic congestion distribution data received from the traffic information distribution server 30. Etc. are stored.

  The traffic information distribution server 30 includes a control unit 300 that controls the entire server, a map data storage unit 301 that stores map display data, a traffic information storage unit 302 that receives and stores traffic information, and a communication network NW. And a line interface 303 for connecting to the network.

  The control unit 300 includes a processor 304 and a memory 305, and a program executed by the processor 304 is stored in the memory 305. As a program related to the present invention, when a traffic information request message designating an area and time is received from the navigation device 10 via the line interface 303, the area specified by the map data storage unit is transferred according to the traffic information request message. The corresponding road data is searched, the traffic information search unit 307 for searching the traffic information data at the specified time corresponding to the road data from the traffic information storage unit, and the specified based on the searched road data and traffic information data A traffic information summarizing unit 308 that generates traffic distribution data with a resolution of a level corresponding to the specified area, and a request response control unit 309 that transmits a response message including the traffic distribution data to the navigation device 10 are stored. Further, the request response control unit 309 may superimpose map display data retrieved from the map data storage unit on the traffic congestion distribution data and transmit it as a response message. As the map display data, for example, road data in a designated area, character data corresponding to a place name of a traffic jam location, and the like are superimposed.

  The map data storage unit 301 and the traffic information storage unit 302 are configured by a large-capacity storage medium such as a hard disk drive. The traffic information storage unit 302 stores collected real-time traffic information and statistical traffic information processed for traffic jam prediction. When the time specified in the traffic information request message is in the future, the traffic information search unit 313 may have a function of performing prediction that takes statistical traffic information and real-time traffic information into consideration.

  FIG. 2 is a diagram illustrating a flow of processing performed between the navigation device 10 and the traffic information distribution server 30 in the traffic information distribution system. First, in the input reception control unit 108 of the navigation device 10, a traffic information request process S <b> 1 for transmitting a traffic information request message specifying a region and time to the traffic information distribution server 30 is performed. When the traffic information request message is received from the navigation device 10, the traffic information distribution server 30 searches the road information corresponding to the designated area from the map data storage unit in the traffic information search unit 307, and the road from the traffic information storage unit. A traffic information search process S2 for searching for traffic information data at a specified time corresponding to the data is performed. Next, the traffic information summarization unit 308 performs traffic information summarization processing S3 for generating traffic congestion distribution data at a resolution of a level corresponding to the designated area based on the road data and traffic information data, and a request response control unit In 306, a traffic information transmission process S4 for transmitting a response message including the congestion distribution data to the navigation device 10 is performed. When the response message is received, in the navigation device 10, the traffic information display unit 109 performs a traffic information display process S5 for displaying the traffic congestion distribution data included in the response message on the display unit 104.

  FIG. 3 is a diagram illustrating a configuration example of data stored in the map data storage unit 101 of the navigation device 10. The map data storage unit 101 stores map display data 40 and link correspondence data 44. The map display data 40 is data for displaying a map on the display unit 104, and is composed of road data 41, background data 42, and character data 43.

  The road data 41 includes road shape data for displaying a road map, and the background data 42 includes background data such as railways, rivers, and buildings. The character data 43 includes annotation character string data such as place names, road names, intersection names, and the like.

  In many cases, road data for car navigation is managed in a data structure based on nodes corresponding to intersections and the like and links connecting the nodes. The road data 41 is data indicating the road shape for each link, and describes the link ID, the number of coordinate points of the shape interpolation points, and the coordinate point sequence of the shape interpolation points in association with each other. Although the data structure is the same as that of the road data 51 of the traffic information distribution server 30 shown in FIG. 5, the specific method of dividing links and attaching IDs differ depending on the map data used in the apparatus. The link correspondence data 44 is data for associating a link used in the map data storage unit 101 of the navigation device 10 with a link used in the map data storage unit 301 of the traffic information distribution server 30.

  The map data for car navigation further includes route search data used during route search, route guidance data used during route guidance, guidance search data used during POI (Point of Interest) search and address search, etc. However, since these data are not related to the present invention, detailed description thereof is omitted.

  FIG. 4 is a diagram illustrating a data configuration example stored in the map data storage unit 301 and the traffic information storage unit 302 of the traffic information distribution server 30. (A) shows the map data storage part 301, (b) shows the example of a data structure corresponding to the traffic information storage part 302, respectively. The map data storage unit 301 stores map display data 50 and includes road data 51, background data 52, and character data 53 as in the case of the navigation device 10. The traffic information storage unit 302 stores traffic information data 60 and includes traffic jam information data 61 and event data 62.

  FIG. 5 is a diagram illustrating a correspondence relationship between the road data 51 in the map data storage unit 301 of the traffic information distribution server 30, the traffic jam information data 61 and the event data 62 in the traffic information storage unit 302. (A) shows road data 51, (b) shows traffic information data 61, and (c) shows data configuration examples corresponding to event data 62, respectively. The road data 51 is data indicating the road shape for each link, and is described in association with the link ID, the number of coordinate points of the shape interpolation points, and the coordinate point sequence. The traffic jam information data 61 is data indicating traffic jam information for each link, and describes a link ID, a travel time, and a traffic jam level in association with each other. The travel time represents the time required for traveling on the link, and the degree of congestion is set according to the average speed, and represents a congestion situation such as smoothness, congestion, and congestion. Here, the congestion degree is described as representing the representative congestion degree for each link, but the link may be further divided so that the congestion degree can be described. The event data 62 is data indicating an event such as an accident or a regulation, and describes the regulation contents and the cause phenomenon of each event in association with a link string. Here, the event occurrence section is described as being described in units of links, but the start point and end point in the link may be described. The traffic jam information data 61 and event data 62 stored in the traffic information storage unit 302 are associated with the road data 51 stored in the map data storage unit 302 by a link ID.

  FIG. 6 is a diagram showing a flow of traffic information summary processing S4 in the traffic information distribution server 30. The traffic information summarization process S4 divides the region into N × M grids and obtains a grid through which each link passes, and the link length sum Li, j (d (d) for each congestion degree included in each grid. ), Step S30 for calculating the traffic congestion distribution Di, j obtained by weighting the sum of the link lengths included in each grid according to the traffic congestion degree, and smoothing the traffic congestion distribution Di, j with the adjacent grid. Step S40 for calculating the smoothed traffic jam distribution D′ i, j, and Step S50 for setting a color corresponding to the smoothed traffic jam distribution D′ i, j for each grid.

  In step S20, assuming that the length of the portion of the link k included in the grid (i, j) is l, the sum of the link lengths Li, j (d) of the congestion degree d included in the grid (i, j). Is given by (1).

In step S30, if the weighting coefficient for the congestion degree d is W (d) and the normalization coefficient is S, the congestion distribution Di, j of the grid (i, j) is given by (2). Here, the normalization coefficient S may be a maximum value of the sum of the lengths of links included in the grid, for example, as shown in (3).

In step S40, if the smoothing filter for smoothing with the adjacent grid is Fa, b, the smoothed traffic jam distribution D′ i, j of the grid (i, j) is given by (4).

In step S40, the smoothing filter Fa, b is given as in (5), for example. Here, if m = 1, it is represented by a 3 × 3 matrix as shown in (6), and smoothing is performed on adjacent grids. If m> 1, it is possible to consider not only the adjacent grid but also the further grid. Further, in (5), the smoothing filter Fa, b is a linear function with respect to the distance, but a Gaussian function or the like may be used.

FIG. 7 is a diagram for describing processing for obtaining a grid through which each link passes and obtaining a link length for each congestion degree included in each grid with respect to an N × M grid. (A) has shown the process which divides | segments an area | region into a grid of NxM in step S10, and calculates | requires the grid which each link passes. The shaded grid here represents a grid through which links pass. (B) represents one of the shaded grids, and shows a process of obtaining the link length for each congestion degree included in each grid in step S20. Here, a dotted line represents a link with a congestion degree of 1, a broken line represents a link with a congestion degree of 2, and a solid line represents a link with a congestion degree of 3.

  FIG. 8 is a diagram illustrating a configuration example of the traffic congestion distribution data 70 distributed from the traffic information distribution server 30. The traffic congestion distribution data 70 includes an area rectangle 71 indicating a distribution area, a grid division number 72, and grid distributions 73 and 74. The area rectangle 71 is represented by, for example, a lower left X coordinate 71a, a lower left Y coordinate 71b, an upper right X coordinate 71c, and an upper right Y coordinate 71d. The division number 72 is represented by an X coordinate division number 72a and a Y coordinate division number 72b. Distributions 73 and 74 are represented by grid coordinates 73a and 74a and grid values 73b and 74b. The grid value represents the smoothed traffic jam distribution of the grid. When the grid value is 0, the distribution may be omitted.

  FIG. 9 is a diagram showing a correspondence relationship between the hierarchical structure of data in the map data storage unit 101 of the navigation device 10 and data distributed from the traffic information distribution server 30 of the present invention. In order to manage the map data for car navigation according to the scale, the map data is managed in several scale levels. The most detailed scale level Level0 is managed in the smallest mesh unit, and the upper level Level1 is managed in a mesh unit obtained by integrating a plurality of Level0 meshes. Further, the higher levels Level2 to Level2 are managed in larger mesh units.

  The traffic information data 60 distributed from the conventional traffic information distribution server 30 corresponds to a detailed scale level, and the corresponding relationship is described by the link correspondence data 44. The congestion distribution data 70 related to the present invention is generated based on the traffic information data 60 and is associated with a wide scale level. The traffic information data 60 may be distributed in the case of a detailed scale level, and the traffic congestion distribution data 70 may be distributed in the case of a wide scale level.

  FIG. 10 is a diagram illustrating a display example of the traffic information data 60 that is input to the traffic information summary process S4, and is also a display example of the traffic information data 60 distributed from the conventional traffic information distribution server 30. FIG. 10 shows an example in which the traffic information 61 in the traffic information data 60 is displayed, and the link is displayed with an arrow of a color corresponding to the degree of traffic. Reference numeral 1 indicates a normal state, 2 indicates congestion, and 3 indicates a traffic jam.

  FIG. 11 is a diagram illustrating a display example of a traffic jam distribution in which the link length of each grid is weighted by the traffic jam degree. When FIG. 10 is input, it corresponds to the result calculated in step S30 of the traffic information summary process S4. The color of each grid is set according to the traffic distribution value of each grid. 4 corresponds to a case where the value of the traffic congestion distribution is small, and 5 corresponds to a case where the value of the traffic congestion distribution is large. The darker the color, the more concentrated the traffic congestion is. Here, the description is made using black and white grayscale display, but hue and saturation may be associated using color display.

  FIG. 12 is a diagram illustrating a display example of the smoothed traffic jam distribution obtained by smoothing the traffic jam distribution with the adjacent grid. When FIG. 10 is input, it corresponds to the result calculated in step S40 of the traffic information summary process S4. Similarly to FIG. 11, 4 corresponds to a case where the value of the traffic jam distribution is small, and 5 corresponds to a case where the value of the traffic jam distribution is large. The darker the color, the more concentrated the traffic jam is. In FIG. 12, since a smaller grid than that in FIG. 11 is set, it is possible to more accurately indicate a location where traffic congestion is concentrated.

  In the display of FIG. 11, when the number of divisions of the grid is increased and the grid is made smaller, it approaches a linear display as shown in FIG. Since FIG. 12 is planarly displayed by smoothing with an adjacent grid, a portion where traffic congestion is concentrated is displayed with a certain extent. As a result, it is possible to make a spot where traffic congestion is concentrated.

  FIG. 13 is a diagram illustrating a display example of a result of extracting a region where traffic congestion is concentrated from the smoothed traffic congestion distribution of FIG. The area where the traffic congestion is concentrated can be obtained, for example, by extracting a grid whose value is equal to or greater than a threshold from the smoothed traffic congestion distribution shown in FIG.

  FIGS. 14 and 15 are diagrams showing display examples when a road map is superimposed on the displays of FIGS. 12 and 13, respectively. By superimposing road maps, it is easy to grasp where traffic congestion is concentrated. Although only road data is superimposed here, background data and character data may actually be superimposed.

The block diagram which shows one Example of the traffic information delivery system to which this invention is applied. The figure which shows the flow of the process implemented between the navigation apparatus 10 and the traffic information delivery server 30 in a traffic information delivery system. The figure which shows the structural example of the data stored in the map data storage part 101 of the navigation apparatus. The figure which shows the data structural example stored in the map data storage part 301 and the traffic information storage part 302 of the traffic information delivery server 30. FIG. The figure which shows the correspondence of the road data 51 in the map data storage part 301 of the traffic information delivery server 30, and the traffic information information 61 and the event data 62 in the traffic information storage part 302. The figure which shows the flow of the traffic information summary process S4 in the traffic information delivery server 30. FIG. The figure for demonstrating the process which calculates | requires the grid which each link passes about NxM grid, and calculates | requires the length of the link for every congestion degree contained in each grid. The figure which shows the structural example of the traffic congestion distribution data 70 delivered from the traffic information delivery server 30. FIG. The figure which shows the correspondence of the hierarchical structure of the data in the map data storage part 101 of the navigation apparatus 10, and the data delivered from the traffic information delivery server 30 of this invention. The figure which shows the example of a display of the traffic information data 60 used as input of traffic information summary process S4. The figure which shows the example of a display of the traffic congestion distribution which weighted the link length of each grid with the traffic congestion degree. The figure which shows the example of a display of the smoothed traffic jam distribution which smoothed the traffic jam distribution by the adjacent grid. The figure which shows the example of a display of the result of having extracted the area | region where the traffic jam is concentrated from the smooth traffic jam distribution of FIG. The figure which shows the example of a display which superimposed the road map on the display of the smoothing traffic congestion distribution shown in FIG. The figure which shows the example of a display which superimposed the road map on the display of the area | region where the traffic congestion shown in FIG. 13 concentrates.

Explanation of symbols

  10: Navigation device, 20: Wireless base station, NW: Communication network, 30: Traffic information server, 100: Control unit, 101: Map data storage unit, 102: Current position acquisition unit, 103: Input unit, 104: Display unit , 105: wireless communication unit, 106: processor, 107: memory, 108: input reception control unit, 109: traffic information display unit, 300: control unit, 301: map data storage unit, 302: traffic information storage unit, 303: Line interface, 304: processor, 305: memory, 306: request response control unit, 307: traffic information search unit, 308: traffic information summary unit.

Claims (9)

A traffic information distribution server connected to a network,
A map data storage unit, a traffic information storage unit, a traffic information search unit, a traffic information summary unit, and a request response control unit;
When a traffic information request message specifying the time and area is received,
The traffic information retrieval unit retrieves road data corresponding to the area from the map data storage unit according to the traffic information request message, and retrieves traffic information data at the time corresponding to the road data from the traffic information accumulation unit. Search and
The traffic information summary unit generates traffic congestion distribution data at a level of resolution according to the area based on the road data and the traffic information data.
The traffic information distribution server, wherein the request / response control unit transmits a response message including the congestion distribution data. The traffic information summary section
The traffic area is divided into grids, the grid through which each link of the traffic information data passes, the length of the link included in each grid is obtained, and the length of the link included in each grid is weighted according to the degree of congestion 2. The traffic information distribution server according to claim 1, wherein a distribution is calculated, and a smoothed traffic congestion distribution obtained by smoothing the traffic congestion distribution with an adjacent grid is calculated.   The traffic information distribution server according to claim 2, wherein the traffic information summarizing unit further sets a color corresponding to the smoothed traffic jam distribution for each grid and delivers the previous traffic jam distribution data as image data. . A traffic information distribution system comprising a traffic information distribution server connected to a network and a navigation device that communicates with the traffic information distribution server via the network,
The traffic information distribution server includes a map data storage unit, a traffic information storage unit, a traffic information search unit, a traffic information summary unit, and a request response control unit.
When the input reception control unit of the navigation device transmits a traffic information request message specifying a time and a region to the traffic information distribution server,
The traffic information distribution server
The traffic information search unit searches for road data corresponding to the area from the map data storage unit according to the traffic information request message, and searches for traffic information data at the time corresponding to the road data,
The traffic information summary unit generates traffic congestion distribution data at a level of resolution according to the area based on the road data and the traffic information data.
The traffic information distribution system, wherein the request response control unit transmits a response message including the congestion distribution data to the navigation device. The traffic information summary section
The traffic area is divided into grids, the grid through which each link of the traffic information data passes, the length of the link included in each grid is obtained, and the length of the link included in each grid is weighted according to the degree of congestion 5. The traffic information distribution system according to claim 4, wherein a distribution is calculated, and a smoothed traffic congestion distribution obtained by smoothing the traffic congestion distribution with an adjacent grid is calculated.   6. The traffic according to claim 5, further comprising a step of setting a color according to the smoothed traffic jam distribution for each grid, and delivering the previous traffic jam distribution data as image data. Information distribution system.   The traffic information display unit of the navigation device retrieves the map display data corresponding to the area from the map data storage unit of the navigation device, and displays the map display data and the congestion distribution data superimposed on each other. Traffic information distribution system characterized by A traffic information distribution method for distributing traffic information data via a network,
Traffic information search processing for searching road data corresponding to the area from a map data storage unit and searching for traffic information at the time corresponding to the road data according to a traffic information request message in which the time and area are specified;
Based on the road data and the traffic information data, a traffic information summary process for generating traffic distribution data at a level of resolution according to the area;
A traffic information distribution method comprising: a traffic information transmission process for transmitting a response message including the congestion distribution data. The traffic information summary process includes:
Dividing the area into grids, obtaining link passing grids of the traffic information data, calculating a traffic jam distribution in which the length of links included in each grid is weighted according to the traffic jam degree, and adjacent traffic jam distributions The traffic information distribution method according to claim 8, further comprising a step of calculating a smoothed traffic congestion distribution smoothed by a grid.