JP2005241613A - Navigation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a map display device of a communication type navigation system, which distributes a map in a shape which is in line with a guidance route, maintains visibility of map displays, and reduces amount of data of a map near the route. <P>SOLUTION: This navigation system is composed of a server device for distributing the route and the map near the route to its map display device, and the map display device for downloading and displaying the route and the map. The server device forms a map near the route, wherein a map region with detail degree different is set, based on the distance from the route. Concerning the formed map near the route, map elements, crossing the border line of the map region having the different degree of detail, are extracted, and correction is made so that the shape of a map element crossing the border line matches at the border line portion of the map region. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a server device that provides route information, and a map display device that transmits and receives position information and the route information to and from the server, and in particular, a server device that divides and distributes a map as the route information, and The present invention relates to a map display device that receives and displays the divided map.

  2. Description of the Related Art Conventionally, a navigation device is known as a device for the convenience of driving a car. There are known a method of reading map data in a navigation device from a local storage medium and a method of downloading from a server through a communication line. The latter method of acquiring map data by downloading from the server has the advantage that the latest map data can be used by the user because the latest map data stored in the server is acquired. However, when downloading map data from the server, the amount of map data becomes a problem. That is, when the amount of map data increases, the map data download time and the response time of the car navigation system increase, and the convenience of the user is lost.

  Therefore, for example, in a car navigation system that downloads map data from a server through a communication line, a method of cutting out a map near the route in an arbitrary shape by the server and transferring it to the in-vehicle device is considered (see Patent Document 1). According to Patent Document 1, by separating and delivering a map from a distance to a predetermined distance or a predetermined intersection, map information of a distant part that is not directly related to route guidance can be omitted, and the amount of map data It can be reduced. When the cut-out width of the belt-like map along the route is specified by the distance, the map data amount increases to include map information that is not directly related to route guidance when the width is large, and appropriate intersections are included when the width is small It may not be possible. If the cut-out width is defined by a predetermined intersection from the route, the map will change if the area near the intersection where the width of the belt-like map is narrow is displayed on the terminal because the width of the belt-like map changes in an area where there is a large variation in the distance between the intersections. An area without a mark may be displayed. In order not to display an area without a map, a method of adjusting the display scale according to the width may be considered. However, the adjusted display scale may not conform to the user's intention.

  On the other hand, a method of cutting out by cutting down the level of detail of the map stepwise as it gets farther from the route is being studied. For example, map data is generated by dividing a route periphery map into a plurality of areas based on the distance from the route, and generating and distributing a route periphery map by cutting out a portion close to the route with a detailed map and a distant portion with a wide area map. It is possible to inform the driver of information existing near the route while reducing the amount.

JP 2001-84493 A (for example, FIG. 4)

  However, when displaying a map around a route composed of a plurality of areas with different levels of detail, there is a problem with the handling of map elements that exist on the boundaries of map areas with different levels of detail. Specifically, when the map elements are divided into shapes having different degrees of detail at the boundary lines, problems such as road junctions not matching, background shapes becoming discontinuous, and names overlapping will occur. If the amount of information is reduced by changing the level of detail in the area away from the route in this way, the map data amount of the map data is reduced, but the above-mentioned inconsistency occurs in the shape of the map element existing at the area boundary. It will damage the sex.

  In view of the above, the present invention has as its main object to provide a map display system that maintains the visibility of a map display even when the data amount of a route periphery map is reduced.

  To achieve the above object, the present invention provides a route search unit that searches for a route to a destination, a map generation unit that generates a route surrounding map including the route, and a route periphery map generated by the map generation unit Map correction means, a server device including a map database referred to when generating the route periphery map, a communication unit with the server device, a vehicle position detection unit for detecting a vehicle position, and the In a server device in a map display system having a client device configured to include a display unit that displays a route periphery map, the map generation unit sets a map area having a different degree of detail based on a distance from the route, and routes A peripheral map is generated, and the map correction unit corrects the shape of a map element that intersects a boundary line of the map area.

  According to this configuration, map data can be efficiently reduced while maintaining map visibility. Other solutions will be described in the following embodiments.

  According to the present invention, in the map display system, the map is provided with a map correction unit that distributes a route surrounding map composed of a plurality of areas having different degrees of detail and further corrects the shape of a map element existing on the boundary of the area. It is possible to deliver and display a map around the route that efficiently reduces the amount of data while maintaining the visibility of the display.

  Hereinafter, an embodiment of a map display system to which the present invention is applied will be described using an example of a navigation system.

  First, the configuration of the navigation system of this embodiment will be described with reference to FIG.

  The navigation system shown in FIG. 1 has a function of cutting out a route surrounding map limited to an area necessary for screen display when performing route guidance and creating efficient map data. Here, the route periphery map is a map that covers the route from the guidance start point to the destination designated by the user. For this reason, the navigation system includes a server device 1 that creates a route periphery map, a client device 2 that presents the route periphery map to the user, and a network 3 that is used for transmission of the route periphery map.

Hereinafter, each device constituting the navigation system of the present embodiment will be described more specifically. First, the server device 1 searches for a route between two points specified using a map database 10, a destination search unit 11 for searching and setting a destination, and a mathematical operation method such as Dijkstra method. A route search unit 12, a route periphery map generation unit 13 that creates a map around the route, a route map correction unit 14 that corrects the transmission map data amount of the route map, and other terminals It has the communication part 15 which is an interface. The communication unit 15 is connected to the network 3. The map database 10 includes road data, background data such as water systems and green spaces, map element data such as name data, facility information such as restaurants and airports, average travel time and distance information of predetermined sections (between intersections), traffic regulation information, etc. And is referred to when generating the destination search, route search, and route periphery map. The client device 2 includes a user interface unit 20, a display unit 21, a communication unit 22, a position detection unit 23, and a control unit 24. The user interface unit 20 is connected with, for example, switches such as scroll keys and scale change keys as input means from the user to the client device 2, a joystick, a touch panel, a microphone, and a speaker as output means from the client device 2 to the user. . As the display unit 21, a CRT or a liquid crystal display is generally used. The communication unit 22 is configured by data communication means using a mobile phone, for example, and is used when communicating with other devices or the server device 1 via the network 3. The position detection unit 23 detects the position of the vehicle on which the client device 2 is mounted. The control unit 24 controls each component configuring the client device 2. The position detector 23 is, for example, a GPS (Global
The received signal from the GPS antenna is input to the position detection unit 23.

  FIG. 2 is an operation sequence for explaining the operation of the navigation system shown in FIG. An operation sequence between the server apparatus 1 and the client apparatus 2 is shown.

  The operation of the navigation system that implements the map display of the present invention will be described below with reference to the operation sequence shown in FIG. First, when an information search request is input together with search information (search key) such as a destination name via the user interface unit 20 of the client device 2 (S201), the search information set in the server device 1 by the above operation. At the same time, a destination search request is issued (S202). When the server apparatus 1 receives the destination search request via the communication unit 15, the destination search unit 11 searches for destination information that matches the search information (search key) (S 203), and the destination unit via the communication unit 15. Search results such as the location address, telephone number, location information, facility information such as a map around the destination and an external photograph, reservation status, and congestion information are returned to the client device 2 (S204). When the client device 2 determines a user-desired destination from the returned destination information (S205), it issues a route search request to the server device 1 (S206). At this time, the user can search for a route that meets the desired conditions by specifying search conditions such as time priority, distance priority, landscape priority, and charge priority. Also, a plurality of routes can be searched by specifying the number of routes to be searched and a plurality of search conditions. The server device 1 that has received the route search request performs a route search by referring to the map database 10 from the current location (or designated point) and destination in the route search unit 12 (S207). The route output by the route search is returned to the client device 2 together with the route identification information (route ID) (S208). The route information returned here is a plurality of route information suitable for the specified search condition, or a plurality of route information calculated under different search conditions such as time priority, distance priority, landscape priority, and charge priority. Sometimes there are. By adding features such as the distance to the destination and the required time to the route and returning it, it is possible to prompt the user to select his / her preference.

  The data format of the route information may be vector data with coordinate values or bitmap data. In the case of bitmap data, the data from the starting point to the destination is synthesized on the map and rendered, but the map data and route data are developed separately and the background of the route data is set to the transparent color. Data that can be combined with map data and displayed can be used. When there are a plurality of routes, a route number is added to the route information as identification information for identifying the route in candidate order. The user selects a preferred route by designating a route number. As the identification information for the user to identify and select the route, in addition to the route number, information that distinguishes colors, shapes, line types, and the like can be considered. If the display color of the route data is made to correspond to the route number (identification information), when the route is selected, the route other than the selected route is made transparent and combined with the map data and displayed. It is also possible to display only.

  When a route is selected in the client device 2 (when the route is a single route, an operation such as pressing an OK button to approve the route to the user side) is performed (S209), route identification information (route ID) At the same time, a route periphery map request is transmitted to the server device 1 (S210). Upon receiving the route periphery map request, the server device 1 generates a route periphery map based on the route selected by the user in the route periphery map generation unit 13 (S211). Subsequently, the route periphery map correction unit 14 executes a correction process for maintaining visibility while reducing the map data amount of the route periphery map according to a procedure described later (S212), and the route periphery map is stored in the client device 2. Distribute (S213). The route periphery map returned here may be vector data or image data obtained by drawing and developing vector data. When a map data format is specified when requesting a route surrounding map, the server device 1 can generate a surrounding map with images or vector data and return it to the client device 2. It is possible to respond to requests from various display devices such as in-vehicle terminals and PDAs. The client device 2 displays the received route surrounding map (S214) and starts guidance (S215).

  Next, a method of reading a plurality of levels of map data having different degrees of detail, such as a detailed map and a wide area map, and generating a route periphery map will be described below with reference to FIG. FIG. 4 shows a map around the route generated by map data at different levels of detail.

In the generation of the route periphery map, the route data of the route 40 from the start point 41 to the end point 42 output by the route search unit 12 is read from the route ID specified in the process of S210 (S301), and the details are based on this route data. A map cutout range 43 and a wide area map cutout range 44 are set (S302). In this embodiment, the amount of map data sent from the server device is provided so that detailed information is provided for the vicinity of the route at the time of route guidance, and the information of the place away from the route is thinned out or provided with an outline. To reduce. For this reason, a map segmentation boundary is set based on the distances r1 and r2 from the route, and the range from the route to r1 is defined in the detailed map area 43,
A range from r1 to r2 is defined as a wide area map area 44. Next, the map data of the detailed map area (detailed map data) and the map data of the wide area map area (wide area map data) are read from the map database 10 (S303), and the map elements included in the detailed map area 43 from the detailed map data, Each map element included in the wide area map area 44 is cut out from the wide area map data (S
304). Road data intersecting with the region boundary 47 is extracted from the detailed map element and the wide area map element cut out in this way, and the shape of the road data is corrected (S305). The process is repeatedly executed until the shape of all the background data intersecting the region boundary 47 is corrected (S306). Then, a duplicate data correction process (S307) is performed so that duplicate name data and the like are not displayed.

As described above, the route periphery map including the map data having two different degrees of detail, the detailed map data and the wide area map data, is generated. For example, the road 45 shown in FIG. 4 is a map element that is recorded in the detailed map data but not in the wide area map data, and has a shape that is cut out from the area boundary 47 to the wide area side in S304. The road 46 is a map element recorded in both the wide area map data and the detailed map data, and the road shape of the detailed map area 43 is generated from the detailed map data, and the road of the wide area map area 44 is The shape is generated from the wide-area map data, and is configured from two different levels of road data. When the map elements at the two different levels are combined and displayed like the road 46, a problem as shown in FIG.

  FIG. 5 shows a display example when two maps having different levels are combined and displayed on one screen 40. Since the wide area map is simplified from the map elements recorded in the detailed map, if the map element that intersects the area boundary 47 is divided at the area boundary 47 and is displayed after being synthesized, the road data is displayed at the dividing point. Disorders such as inconsistency (51) that cannot be joined and mismatch (52) in which the joined portion does not match between the detailed map shape (surface) and the wide area map shape (line) occur. Moreover, since the name data of the map element which cross | intersects an area | region boundary line is contained in both map data, it may happen that the same name is displayed repeatedly (53). The correction process for preventing such inconsistency will be described more specifically with reference to FIGS.

  FIG. 6 is a flowchart for explaining a correction process for preventing an inconsistency where road data cannot be joined at a region boundary line. In the road data correction process (S305), the correction process is performed on the detailed map data and the wide area map data. The road data is represented by node (intersection) coordinates and a link string connecting the nodes. First, correction processing is performed on the road data of the detailed map. Among the route surrounding maps cut out in the process S304 of FIG. 3, one road data (hereinafter referred to as a detailed road) recorded in the detailed map is read (S601), and the data of the road intersecting the area boundary 47 is read. Is checked (S602). If the corresponding road data is data of a road intersecting with the area boundary 47, the node data existing in the wide area map area 44 is read (S605), and the roads recorded in the wide area map (hereinafter, It is detected whether or not there is an intersection with a wide area road (S606). If a node corresponding to the intersection is included in the wide area map area 44, the node is set as a junction, and the road data is clipped at this junction (S608). On the other hand, when the node corresponding to the intersection is not included in the wide area map area 44, the road data is clipped at the area boundary 47 (S607). Then, the road shape based on the clipped road data is registered in the route periphery map as a map element of the detailed map area 43 (S609). The above processing is executed for all the detailed roads existing in the detailed map area (S604), and a surrounding map of the detailed map area is generated.

For example, as shown in FIG. 7, since the road data 83 recorded in the detailed map intersects with the region boundary 47, nodes existing in the wide area map region 44 beyond the region boundary 47 are sequentially read in step S605, and processing 606 is performed. To detect an intersection with a road (hereinafter referred to as a wide area road) recorded in a wide area map. In the case of the road data 83, the intersections with the wide area road are searched in the order of the intersections 81 and 89. However, since they exist as a result, the shape is clipped at the region boundary 47 by the processing S607, and the road shape 86 is generated. The Similarly, the detailed road 84 sequentially searches for intersections with the wide area road in the order of the intersections 81 and 82 by the processing 606. Since the intersection 82 becomes an intersection with the wide area road, the intersection 82 is set as a junction between the detailed road and the wide area road, and the road 84 is clipped at this junction by processing S608 to generate a road shape 87. The road shapes 86 and 87 generated in this way are registered in the route surrounding map as map elements existing in the detailed map area 43.

  Next, a process for correcting the road data of the wide area map data intersecting with the area boundary 47 is performed. One road data recorded in the wide area map is read from the map around the route cut out in the process S304 in FIG. 3 (S610), and it is checked whether the road data intersects with the area boundary 47 (S611). ). If the corresponding road data is data of a road that intersects the region boundary 47, the road data is clipped at the intersection corresponding to the junction set in the above-described processing S608 (S614). Then, the road shape based on the clipped road data is registered in the route periphery map as a map element of the wide area map area 44 (S615). The above processing is executed for all the detailed roads existing in the wide area map area (S613), and a surrounding map of the wide area map area is generated.

  In the example shown in FIG. 7, since the wide area road 85 intersects with the region boundary 47, the road shape is clipped at the junction point set in step S608 (in this case, the intersection 82) by processing 614 to generate the road shape 88. . The road shape 88 is registered in the route periphery map as a map element of the wide area map area 44. In this example, a node of a detailed road that intersects with a wide area road is set as a junction point so that the detailed road data and the wide area road data can be joined. It is preferable to store it in the map database 10.

  As described above, the method for correcting the road data and generating the route surrounding map with the map data having different levels of detail has been described. Next, background data correction processing (S306) will be described below.

FIG. 9 is a flowchart showing the procedure of background data correction processing. In FIG. 9, the background data (hereinafter referred to as detailed background) recorded in the wide area map of the route surrounding map is read (S901), and it is checked whether this background data exists in the wide area map area 44 (S902). If it exists in the wide area map area 44, the entire shape of the background data is clipped (S906). For example, as shown in FIG. 8, since the detailed background 802 recorded in the detailed map data is present in the wide area map area 44, the entire shape is cut out by the clipping processing in step S906. If the background data does not exist only in the wide area map area 44, it is next checked whether or not it intersects with the area boundary 47 (S903). When the detailed background intersects the region boundary, the background shape is clipped by the region boundary line (S905), and the portion protruding to the wide area map region 44 is clipped. Since the detailed background (green space) 1101 and the river 1103 shown in FIG. 11 are background data intersecting with the region boundary 47, the portion protruding toward the wide-area map region 44 is cut off in the clipping processing in step S905. .

  Next, background data (hereinafter, wide area background) is read from the wide area map (S907), and it is checked whether it is a wide area background located in the detailed map area 43 (S908). If the entire shape is located in the detailed map area 43, The background data is clipped (S912). Since the green space 1105 shown in FIG. 11 is a wide area background existing in the detailed map area, it is cut out by the process S912. If the entire shape of the wide area background is not located in the detailed map area 43, it is checked whether the wide area background intersects with the area boundary 47 (S909). If it is a wide area background that intersects the area boundary 47, the entire shape of this background data is registered in the route periphery map (S911). That is, as for the wide area background that intersects the boundary, the entire shape is registered in the route periphery map regardless of the area. In this example, the background data that intersects the region boundary has been described as a method of generating a route map at multiple map levels (detail and wide area) with different levels of detail. It is also conceivable to generate a peripheral route map with any of the details.

  In addition, about the duplication data correction process (S307) which prevents duplication (53) display of name data, the map element which cross | intersects the area | region boundary 47 is extracted from a route periphery map, the map element of the detailed map area 43, and the wide area map area 44 Name data is compared with other map elements, and if there is a duplicate name, one of the names is deleted, thereby preventing duplicate display of the name data. In addition to the method for detecting and deleting duplicate names on the server side, there is a method for detecting and deleting duplicate names on the client side. In order to reduce the amount of map data, it is advantageous to remove duplicate names on the server side.

  In the foregoing, a method has been described in which multiple levels of map data with different degrees of detail, such as detailed map data and wide area map data, are read from the map database 10 and the route surrounding map is generated by correcting the shape of map elements.

  In addition, there is also a method of generating a route surrounding map from single-level map data, in which the detailed map data is read to simplify the shape, and the shape of the map element on the region boundary is corrected to generate a route surrounding map. This method will be described with reference to FIG. FIG. 10 is a processing flow for reading the detailed map data, simplifying the shape of the map element away from the route, and correcting the shape of the map element that intersects the region boundary.

Based on the route ID specified in the process S210, the route data of the route 40 from the start point 41 to the end point 42 output by the route search unit 12 is read (S1001), and an area for cutting out the map in a band shape is set based on the route data. (S1002). The detailed map data of the area set from the map database 10 is read (S1003), and the map data existing in the area set in the process S1002 is cut out (S1004). These processes are repeated until the route surrounding map (the map of the area set in S1002) is cut out (S1005). The map element data of the detailed map is read from the route surrounding map generated in this way (S1006), the map element existing at a position exceeding a predetermined distance from the route 40 is detected (S1007), and the shape of the map element is detected. Is simplified (S1012). At this time, if the map element is road data, the shape of the road link is simplified. In addition, a detailed map area and a wide area map area are set according to the distance from the route, and whether or not the map element intersects with these area boundaries is checked (S1008). Adjust so that no alignment occurs. For map elements existing on the region boundary, the junction point with the region boundary line is set as a division point that divides the shape of the map element (S1010), and the map element shape on the wide-area map region side is simplified from this junction point. (S1011). This process is repeated until the correction process is completed for all map elements (S1009).

  The above-described processing will be described with respect to road shape simplification and road shape correction processing using road data as an example. In the case of a road link (a line connecting road nodes) that is more than a predetermined distance from the route 40, the shape is simplified by thinning out interpolation point data for expressing road shape characteristics in step S1012. Here, not only simplification of the link, but it is also conceivable to thin out detailed road data such as narrow streets based on road attributes such as road width and city roads. Both are effective methods for reducing the amount of map data. Next, in the case of road data that intersects the predetermined distance from the route, that is, the area boundary between the detailed map and the simple map, the intersection of the road link and the area boundary line is calculated in step S1010 and the junction point of the road is set. In step S1011, road data close to the route with this dividing point as a boundary is generated in a detailed shape, and distant road data is generated in a simple shape, and shape data having different degrees of detail are joined at joint points. It is also conceivable that identification information for identifying these junction points is added to the route periphery map and distributed. By adding joint point identification information, it is possible to join and display the shapes of map elements having different levels of detail (levels) even if the coordinates of the joint points do not match.

  As described in FIG. 9, the background data includes both the detailed shape and the simple shape of the background data existing on the region boundary in the route periphery map. At this time, it is also conceivable to add the identification information for identifying the same background having different levels of detail (levels) to the route surrounding map for distribution. As a result, the client device 2 can select and display one of the backgrounds having different degrees of detail using the identification information.

  FIG. 11 is a processing flow illustrating an example of processing in the display unit 21 of the client device 2 that displays the route periphery map generated by the server device 1.

When the display range of the map is set (S1101), the route surrounding map data received via the communication unit 22 is read (S1102). Here, it is assumed that the route periphery map data is stored in an internal memory mounted on the client device 2 or a removable external storage means such as a memory card. Whether or not the region boundary 47 exists in the display range is checked (1403). If the region boundary 47 exists in the display range, the background data intersecting with the region boundary line is drawn and developed with the background data of the wide area map (simple shape) ( 1104). Further, it is checked whether or not the scale of the map to be displayed is equal to or greater than a predetermined value (S1105). If the display scale is equal to or greater than the predetermined value, a predetermined type of road is not displayed in the detailed map data existing in the detailed map area 43. The drawing is thinned out as described above (S1106). The above processing is performed for all map elements to be displayed (S1107). Thereby, since the road clipped by the area boundary line, such as the road 45, is not displayed on the screen in a shape cut off in the middle, a display without a sense of incongruity becomes possible.

  INDUSTRIAL APPLICABILITY The present invention is suitable for distribution of a route periphery map that efficiently reduces the amount of data while maintaining the visibility of a map display in a communication navigation system.

1 is a configuration diagram of a map display system according to an embodiment of the present invention. The operation sequence of this system is shown. It is a processing flow which shows the procedure which produces | generates the route periphery map which consists of several area | regions from which a detailed degree differs. A route surrounding map generated by map data of different levels of detail is shown. This is a display example when two maps with different levels are combined and displayed on one screen. It is a processing flow which shows the procedure which corrects the road data of the map data which cross | intersects a boundary. It is a figure explaining the correction method of road data. It is a figure explaining the correction method of background data. It is a processing flow which shows the procedure which corrects the background data of the map data which cross | intersects a boundary. It is a processing flow which shows the procedure which simplifies the map element away from the path | route. It is a processing flow which shows an example of the process in a display part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Server apparatus, 2 ... Client apparatus, 3 ... Network, 10 ... Map database, 11 ... Destination search part, 12 ... Route search part, 13 ... Route periphery map generation part, 14 ... Route periphery map correction part, 15, 22 ... Communication unit, 20 ... User interface unit, 21 ... Display unit,
23: Position detection unit, 24: Control unit.

Claims (4)

A route search unit that searches for a route to the destination, a map generation unit that generates a route surrounding map including the route, a map correction unit that corrects the route surrounding map generated by the map generation unit, and the route surrounding map A server device configured to include a map database referred to when generating
And a navigation system having a client device configured to include a communication unit with the server device, a vehicle position detection unit that detects a vehicle position, and a display unit that displays the route surrounding map.
The map generation unit generates a route periphery map by dividing the route periphery map into a plurality of areas having different degrees of detail,
The map correction unit corrects the map elements intersecting the boundary lines of the divided areas so that the shape of the map elements in the respective areas is continuous at the junction provided on the boundary line. .   2. The map correction unit according to claim 1, wherein the map correction unit divides road data intersecting with a boundary line of the map area at a road node common to the plurality of areas existing closest to the boundary line. Navigation system.   In Claim 1, the said map correction part further detects whether the name data of the map element contained in the area | region of these several maps overlaps, and selects and displays any one of the overlapping names. A navigation system characterized by A vehicle position detection unit that detects the position of the vehicle, a route search unit that searches for a route to a destination in response to a request from a navigation terminal device that includes a display unit that displays the map around the route, and A map generating unit that generates a route surrounding map that covers the searched route, a map correcting unit that corrects the route surrounding map generated by the map generating unit, and a map database referred to when generating the route surrounding map In a navigation system server device comprising:
The map generation unit generates a route periphery map by dividing the route periphery map into a plurality of areas having different degrees of detail,
The map correction unit corrects the map elements intersecting with the boundary lines of the divided areas so that the shape of the map elements in the respective areas is continuous at the junction provided on the boundary line. .

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