JP2005165639A - Difference map data generation device, map data update device, difference map data generation program and map difference update system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a map difference update system allowing sharing of update information between users without necessity to manage the update information in each map version or each map format. <P>SOLUTION: Update map data including the update information about map data are stored in a form wherein a class or an object is managed by a tag such that the update map data do not depend on a specific map format, and are distributed to a user. The user generates difference map data according to the map data of oneself by use of a difference map data generation device, and uses them in a navigation device. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a difference update system for map data used for a navigation device or the like, and more specifically, a map difference that does not require update information management for each map version or map format and can share update information between users. Regarding the update system.

Conventionally, a navigation system using an in-vehicle navigation device is known as a map difference update system. A navigation system capable of updating map data includes means for wirelessly receiving the latest map data in the area requested by the user, and replacing the map data held by the user with the latest map data received, Map data is created. However, in the past, since the map data of the entire area to be updated is transmitted even if the data actually updated is a little, the amount of communication is wasted, but the map owned by the user (hereinafter referred to as the original map) The map difference update method is disclosed in which the original map is updated using the received difference map data (see, for example, Patent Document 1 and Patent Document 2).
JP-A-4-46379 Japanese Unexamined Patent Publication No. 7-36382

  However, in the map difference update method, since the recorded data differs depending on the version of the original map, the difference map data also differs depending on the version. For this reason, the side which supplies difference map data is provided with the mechanism which produces | generates difference map data beforehand for every version of an original map, or acquires the version of an original map and produces | generates the difference map data according to a version. There is a need. In the former case, as the version increases, the cost for managing and maintaining the difference map data becomes enormous. In the latter case, a complicated version management method is required in which update information is included in which version of the difference map data.

  In addition, there is a need to exchange update information between users or to publish update information on the Internet site, but it is necessary to use different difference map data for each map format. It is limited to users who hold a specific navigation device, and sharing among all users cannot be realized.

  The present invention has been made to solve such a problem. In addition to management of update information for each map version, update information management for each map format is unnecessary, and update information is shared among all users. It is an object to provide a difference map data generation device, a map data update device, a difference map data generation program, and a map difference update system that can be shared among users by exchanging update information or making it public And

  In order to achieve the above object, the difference map data generation device of the present invention compares an update map data acquisition means for acquiring update map data including update information of map data, the map data and the update map data. Map object identity determining means for determining the same object, and difference map data generating means for generating difference information that does not exist in the map data from the updated map data using the result of the map object identity determining means. It has the composition provided.

  With this configuration, not only update information management for each map version, but also update information management for each map format is not required, and update information can be shared among all users. Can be shared among users.

  Moreover, the difference map data generation device of the present invention is characterized in that the updated map data acquisition means acquires the updated map data by communication. With this configuration, it is possible to easily obtain updated map data.

  In the difference map data generation device of the present invention, the map object identity determination means compares objects using at least one of the position and shape of the object. With this configuration, it is possible to easily determine whether an object is identical.

  Moreover, the difference map data generation device of the present invention is characterized in that the map object identity determination means compares objects using attribute information of the object. With this configuration, it is possible to increase the accuracy of the object determination.

  Moreover, the difference map data generation device of the present invention is characterized in that the map object identity determination means compares objects using a connection relationship between objects. With this configuration, it is possible to increase the accuracy of the object determination.

  In the difference map data generation device according to the present invention, the updated map data includes information in the vicinity of the update information, and the map object identity determination unit compares objects using a connection relationship with the information in the vicinity. It is characterized by doing. With this configuration, it is possible to increase the accuracy of the object determination.

  Further, the present invention relates to an update map data acquisition means for acquiring update map data including update information of map data, and compares the map data with the update map data to determine the same object. Means for extracting difference information that does not exist in the map data from the updated map data, and map data updating means for combining the difference information with the map data. This is a map data update device characterized by that.

  With this configuration, not only update information management for each map version, but also update information management for each map format is not required, and update information can be shared among all users. Can be shared among users.

  Further, the present invention compares the map data with the updated map data, and uses the map object identity determination step for determining the same object, and the difference that does not exist in the map data using the result of the map object identity determination means. A difference map data generation program for causing a computer to execute the difference map data extraction step of extracting information from the updated map data and a step of storing the difference map data.

  By using this program, not only the update information management for each map version, but also the update information management for each map format is unnecessary, and the update information can be shared among all users, and the update information is exchanged. And sharing between users, such as sharing and publishing.

  Further, the present invention includes a difference map data generation device and a navigation device, and the difference map data generation device includes update map data acquisition means for acquiring update map data including update information of map data, and the map data. And the updated map data, the difference information not existing in the map data is obtained from the updated map data by using the result of the map object identity determining means and the map object identity determining means for determining the same object. Difference map data generation means for generating, the navigation device acquires at least map data from the difference map data generation device and displays the map, at least one of map display and route guidance using the map data It has the structure provided with the means to perform one.

  With this configuration, not only update information management for each map version, but also update information management for each map format is not required, and update information can be shared among all users. Can be shared among users.

  In the map difference update system of the present invention, the navigation device obtains update map data including update information of map data from the difference map data generation device, the map data, and the update map. Map object identity determining means for comparing the data and determining the same object; means for extracting difference information not existing in the map data from the updated map data using the result of the map object identity determining means; And a map data updating means for synthesizing the difference information with the map data. With this configuration, it is possible to update its own map data based on the update map data including the update information of the map data from the difference map data generation device.

  Moreover, the map difference update system of the present invention is characterized in that the difference map data generation device generates and outputs update map data by combining the generated difference map data with an original map in advance. With this configuration, the navigation device does not need to update its own map data and can immediately use the updated map data from the difference map data generation device.

  In the map difference update system of the present invention, the difference map data generation device and the navigation device exist for each map format of the map data, and the difference map data generation means of the difference map data generation device includes the format. The difference map data according to is generated. With this configuration, even if the format of the map data that you own is different from the format of the map data that other people have, you can generate the difference map data according to your map Update information can be shared among all users.

  In the map difference update system of the present invention, the difference map data generation device is included in the navigation device. With this configuration, it is possible to generate difference map data and update map data using the difference map data with a single navigation device.

  The map difference update system of the present invention includes a center that holds the updated map data, and the navigation device connected to the center via a network, and the updated map data acquisition unit of the navigation device includes the updated map. Data is requested from the center, and the center transmits the requested updated map data to the navigation device. With this configuration, each user connected to the network can register the updated map data created by him / her in the center, download the updated map data released from the center, and have his / her own map data Can be updated.

  The present invention compares the map data with the acquired updated map data, determines the same object, and uses the result of this map object identity determination means to generate difference information that does not exist in the map data from the updated map data Therefore, not only the update information management for each map version but also the update information management for each map format is unnecessary, the update information can be shared among all users, and the update information can be exchanged or released. It is possible to provide a difference map data generation device, a map data update device, a difference map data generation program, and a map difference update system that can be shared among users.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of the map difference update system according to the embodiment of the present invention. In FIG. 1, the map difference update system includes a difference map data generation device 1 and a navigation device 7. The difference map data generation device 1 includes a control unit 2 including a CPU that controls the difference map data generation device, an input unit 3 including various devices for a user to operate the difference map data generation device, and processing results. It comprises an output unit 4 that is presented to the user through a monitor, a map data storage unit 5 that is a recording device that stores map data, and a communication unit 6 that transmits and receives information such as map data. The communication unit 6 constitutes update map acquisition means for acquiring update map data from the outside. The control unit 2 compares the map data with the acquired updated map data, and uses, for example, a map object identification determination unit that determines the same object managed by the tag and a map object identification determination unit, Difference map data generating means for generating difference information that does not exist in the data from the updated map data is configured, and a program for realizing these means stored in the memory is executed. The generated updated map data is presented to the user by the monitor of the output unit 4 and is transmitted from the communication unit 6 to the navigation device 7.

  The navigation device 7 presents information using the map data to the user through a monitor, a control unit 8 comprising a CPU for controlling the navigation device, an input unit 9 comprising various devices for the user to operate the navigation device. And a map data storage unit 11 which is a recording device for storing map data and the like. The input unit 9 constitutes update map data acquisition means for acquiring update map data including update information of map data from the difference map data generation device 1. The control unit 8 compares the map data with the acquired updated map data, and uses the results of the map object identity determination means for determining the same object and the map object identity determination means, and the difference information that does not exist in the map data Is extracted from the update map data, and map data update means for combining the difference information with the map data, and a program for realizing these means stored in the memory is executed. The control unit 2 also displays the map on the monitor of the output unit 4 using the map data, guides the route on the monitor using the map data, or displays the map and the route guidance on the monitor. The control which performs both of these is also executed. The output unit 4 presents the map to the user through the monitor based on the synthesized map data. As long as the navigation apparatus 7 has such a configuration, it may be a navigation apparatus using a mobile phone or a personal computer as well as the in-vehicle navigation apparatus.

  Next, the update map data used in this embodiment will be described. First, an example of general map data is shown in FIG. The map data is managed for each rectangular area 21 (also called a parcel) in consideration of the efficiency in reading the data into the memory. In many cases, a plurality of hierarchies 22 are provided in order to reduce the size of data read into the memory. For example, a high-level map having a wide area range with a feature shape is used in a wide-scale map display, and a lower-layer map having a fine feature shape and a narrow area range is used in a detailed scale map display. The data representing the road network in the map data is composed of nodes 23 representing intersections and links 24 having the nodes at both ends. In addition to storing each other's connection information in nodes and links, attribute information related to roads such as road type, road name and route number, attribute information related to intersections such as intersection names and lane information, one-way traffic and intersection restrictions, etc. Attribute information about traffic regulation is stored. In addition to the road network, the map data also stores various information such as background 25 and characters 26. Depending on the format, continuous links with the same attribute information are gathered and called a link string (or road), and map data is managed in units of link strings, or nodes arranged on the boundary of the area 21 are boundary nodes. Some call it distinct from a node representing an intersection. The division and width of the area 21, the method of expressing the position in the area 21 (coordinate system), the number of layers 22, and the like all differ depending on the map format. In the following, nodes, links, backgrounds, and characters are called classes. Each class element (for example, each node) is called an object.

  Next, FIG. 3 shows an example of updated map data in the present embodiment. Update map data 31 shown in FIG. 3 is update map data when the map data 32 at the bottom of FIG. 3 is updated. That is, the update map data 31 adds a road bridge 32 over the Tama River and a character 33 indicating the name of the bridge to the map data 32. Data in the vicinity of the update information (data that already exists in the map data) is also added to the update map data 31. In the case of FIG. 3, nodes 34, links 35, and the like that are in the vicinity of the road bridge 32 are also added as updated map data. This is to increase the accuracy of the map object identity determination means described later by using the connection relationship with the existing map data 32.

  The updated map data 31 does not have the concept of the area 21 in conventional general map data. A set of update information is handled as one update map data. In general map data, the position of an object such as a node or a link is expressed by normalized coordinates in the area 21, but the updated map data 31 in the present embodiment does not have the concept of an area. Is expressed in absolute coordinates. The updated map data 31 is not a plurality of hierarchies 22 but one hierarchy, and further uses basic object classes such as nodes, links, backgrounds, and characters without using format-specific concepts such as link strings and boundary nodes. Store in the format.

  An example of the format of the update map data 31 is shown in FIG. In the example of FIG. 4, the XML (Extensible Markup Language) format is used, but other text formats such as TSV (tab delimited) may be used, or a binary format may be used. Each object is managed by a tag 41 indicating the class of the object. For example, a tag of <Node> indicates a node class object. Further, the attribute information of the object is also managed by a tag 42 uniquely determined for each attribute. In this way, by managing the classes and attributes by the tags 41 and 42, even when the format of the original map is expanded, it is only necessary to add a new tag, and there is no need to change the format of the updated map data 31. . Also, the attribute information included in the map data varies depending on the format, but if the difference map data generation device interprets only the attribute tags present in the original map and skips the other tags, the format information Only the corresponding update information can be extracted. Therefore, in this embodiment, by taking such a format of the update map data 31, it can be used in navigation devices of various map formats, and update information management for each map format is not required. By sharing it among all users, it becomes possible to share between users such as exchanging update information and making it public.

  Next, the operation of the present embodiment will be described. FIG. 5 shows the operation of the difference map data generation apparatus 1. The map difference update is performed when a map data update instruction is input from the user through the navigation device 7. Specifically, an update instruction is input by the user selecting an update menu. When an update instruction is input, difference map data is generated in the difference map data generation device 1 as shown in FIG. First, in step S <b> 11, updated map data is acquired through the communication unit 6. The updated map data may be acquired from a server by wireless communication, or may be acquired from a site such as a center through the Internet. Further, it may be recorded in a removable storage device and read by the difference map data generation device. When there are a plurality of updated map data, a list may be displayed to allow the user to select. Difference map data corresponding to a map owned by the user (hereinafter referred to as an original map) is generated using the updated map data acquired and selected here. The original map is stored in advance in the map data storage unit 5 of the difference map data generation apparatus 1 or is recorded in a removable storage device so that the difference map data generation apparatus 1 reads it.

  Next, in step S12, a map object identity determination process is performed. Here, with respect to all the objects existing in the update map data, it is determined whether or not the same object exists on the original map side, and if so, which one. Here, the object indicates individual nodes, links, backgrounds, and characters (nodes, links, backgrounds, and characters as aggregates are called object classes), and are managed by tags as described above.

  FIG. 6 is a flowchart showing in more detail the procedure of the map object identity determination process. As shown in step S21, the object identity determination process is performed by the number of all objects present in the updated map data. First, in step S22, the same object extraction process on the original map side is performed. Here, candidates that are considered to be the same as the object of the updated map data are extracted from the original map side. Specifically, an original map side object that belongs to the same object class as the object of the update map data and is included within a certain distance from the object of the update map data is extracted as a candidate. Next, the process proceeds to step S23, and evaluation value calculation processing is performed for the number of candidates extracted in step S22. The lower the evaluation value calculated here, the higher the possibility that it is determined that the object is the same.

  FIG. 7 is a flowchart showing the details of the evaluation value calculation process. First, in step S31, the object class is checked. Here, in the case of a class of one-dimensional data such as a node or a character, the process proceeds to step S32, and an evaluation value due to a positional deviation is added. On the other hand, in the case of a class of multidimensional data such as a link or a background, the process proceeds to step S33, and an evaluation value due to a shape shift is added. The evaluation value based on the position or shape deviation is calculated based on the difference in the coordinates of the object.

  Next, in step S34, the object class is checked again. Here, in the case of belonging to a class having a connection relationship between objects such as nodes and links, the process proceeds to step S35, and an evaluation value based on the connection relationship is added. For the evaluation value based on the connection relationship, the evaluation value is calculated for all the objects connected to the evaluation target object, and the average value is added. Since the updated map data stores not only the update information but also existing objects in the vicinity thereof, the accuracy of the same determination can be improved by adding the connection relationship with the existing object to the evaluation value.

  Next, it progresses to step S36 and the evaluation value by attribute information is added. For example, in the case of a node, an intersection name, presence / absence of a signal, presence / absence of a toll booth, intersection restriction, and the like are compared, and “0” is added when they match, and a constant value is added when they do not match. In the case of a link, the road type, road name, route number, one-way traffic restriction, and the like are compared, and “0” is added when they match, and a constant value is added when they do not match.

  In this way, when the evaluation value calculation process is performed in step S23, the process proceeds to step S24, where it is checked whether there are evaluation value candidates equal to or less than the same determination upper limit. The same determination upper limit is a standard value that determines that the same object is determined if the value is equal to or less than this value. If it exists, the process proceeds to step S25, and the object with the lowest evaluation value is determined as the same object from the candidates. On the other hand, if there is no evaluation value candidate equal to or lower than the same determination upper limit, it is determined in step S26 that there is no object that can be determined to be the same.

  As described above, when the map object identity determination process is performed in step S12, the process proceeds to step S13, where the difference map data extraction process is performed.

  FIG. 8 is a flowchart showing the details of the difference map data extraction process. As shown in step S41, the difference map data extraction process is performed by the number of all objects existing in the updated map data. First, in step S42, it is checked whether there is an identical object. Here, the result of the map object identity determination process is used. If there is no identical object, the process proceeds to step S43. Here, the update type of the object is checked. Here, the update type includes new addition, attribute change, and existing deletion. Here, when the update type is existing deletion, the difference map data is not added, and the processing of the object is terminated. On the other hand, if the update type is new addition or attribute change, the process proceeds to step S44. Here, the object of the update map data is added as newly added difference map data. The newly added difference map data includes all attribute information included in the object of the updated map data.

  In step S42, if the same object exists, the process proceeds to step S45, and the update type of the object is checked. If the update type is existing deletion, the process proceeds to step S46, and the object of the update map data is added as existing deletion type difference map data. The existing deletion type difference map data is used when data is deleted from the original map, and only the ID of the original map side object to be deleted is described. The attribute information existing in the updated map data is not recorded because it is unnecessary. On the other hand, if the update type is new addition or attribute change, the process proceeds to step S47. Here, all the attribute information on the updated map data side and the original map side is compared, and the attribute information to be changed is extracted. Specifically, the attribute information is extracted when attribute information that does not exist on the original map side exists on the updated map data side, or when the attribute information differs between the updated map data side and the original map side. Next, the process proceeds to step S48, where the object of the updated map data is added as attribute-change type difference map data. The ID of the original map object whose attribute is to be changed and the attribute information to be changed or added are recorded.

  Thus, if the difference map data extraction process is performed in step S13, it will progress to step S14 next and difference map data will be produced | generated. Here, the difference map data extracted in step S13 is stored in a file or the like. If necessary, perform region division and hierarchization according to the format of the original map. Step S15 will be described later.

  After the difference map data is generated in the difference map data generation device 1, the difference map data is transferred to the navigation device 7. Various forms of the difference map data transfer method are conceivable. There are a method of storing in a removable storage medium such as a memory card and causing the navigation device 7 to read the data, a method of receiving from the difference map data generating device by communication, and the like. Here, it is assumed that the data is acquired by communication at the input unit 9 of the navigation device 7 and stored in the map data storage unit 11.

  On the navigation device 7 side, map data is read from the map data storage unit 11 by the operation shown in FIG. First, in step S51, the original map is read. Next, it progresses to step S52 and it is checked whether difference map data exists. Here, when there is no difference map data, the process is terminated. That is, as with the conventional navigation system, map display and route guidance are performed using only the original map. On the other hand, if the difference map data exists, the process proceeds to step S53, and the difference map data is read. In step S54, the difference data is combined with the original map. As a result, the original map is updated with the difference map data, and map display and route guidance are performed using the latest map data.

  Next, sharing of updated map data using the present embodiment will be described. As described above, in this embodiment, by managing classes and attributes using tags, update information can be shared among all users, and the update information can be exchanged or released. Sharing is possible.

  FIG. 10 is a diagram illustrating a data flow of the map difference update system in the present embodiment. Each user connected via the network prepares the difference map data generation device 1 corresponding to the format of the map data held by the user. When the updated map data is distributed, the user uses the difference map data generation device 1 to generate the difference map data corresponding to the map owned by the user. Since the stored data differs depending on the map version, the contents of the difference map data generated even in the same map format are different. Moreover, the format of difference map data differs for every map format. That is, the difference map data of Taro, Jiro and Hanako are all different data. In the conventional map difference update system, since the difference map data is distributed, the contents of the data differ depending on the map version and the map format, and the update information cannot be shared. In the map difference update system according to the present embodiment, update map data that can be commonly used by all users managed by tags as update information is distributed, so that update information can be shared among all users. .

  FIG. 11 is a diagram illustrating sharing of update information according to the present embodiment. Taro, who has a device connected via a network such as the Internet, creates updated map data in order to update his own map data. Taro exchanges updated map data with his friend Jiro, and Jiro updates his map data using the updated map data created by Taro. Furthermore, in order to have more people use the updated map data created by Taro, he registers the created updated map data in a center, which is a site on the Internet, and publishes it on the Internet. Hanako downloads the updated map data released from the center and updates the map data that she owns.

  Thus, the map difference update system of this Embodiment is provided with the difference map data generation apparatus 1 and the navigation apparatus 7, and the difference map data generation apparatus 1 acquires the update map data containing the update information of map data. The communication unit 6 that compares the map data with the acquired updated map data, determines the same object managed by the tag, and uses the result of the map object identity determination means, and the difference information that does not exist in the map data The navigation device 7 generates the update map data using the map data and the difference map data, and includes the map display and the route guidance using the update map data. Since the control unit 8 executes at least one of the above, not only the map version but also the update information management for each map format is not possible. And then, the update information by common between all of a user, to exchange updated information, it is possible that the inter-user sharing, such as to publish to realize the map difference updating system as possible.

  In the present embodiment, the case where the difference map data is placed separately has been described. However, the difference map data can be combined with the original map in advance to generate updated map data. In that case, after step S13 is completed in the flowchart of the map difference update means shown in FIG. 5, the process proceeds to step S15. Here, the difference map data and the original map are combined to generate updated map data. In this case, the navigation apparatus side can use the map data as usual without performing special processing as shown in S52 to S54 in FIG.

  In the present embodiment, the difference map data generation device 1 and the navigation device 7 are separate devices, but two devices can be combined into one. In the present embodiment, it is assumed that the difference map data generation device 1 is a separate device on the assumption that a home personal computer is used and the in-vehicle navigation device is used as the navigation device 7. In this case, the difference map data is generated in advance at home, and it is brought into the car and used. However, the in-vehicle navigation device has sufficient storage device and processing capability, and the difference map data can be generated in a short time. For example, the function of the difference map data generation device may be included in the in-vehicle navigation device.

  As described above, the map difference update system according to the present invention compares the map data with the acquired updated map data, determines the same object, and uses the result of this map object identity determination means, Difference information that does not exist in the map is generated from the update map data, so not only update information management for each map version but also update information management for each map format is unnecessary, and update information can be shared among all users It is possible to share between users, such as exchanging update information or publishing it, and it is useful as a map data difference update system used for a navigation device or the like.

The block diagram which shows the basic composition of the difference map data generation apparatus and navigation apparatus which concern on embodiment of this invention Schematic diagram showing an example of map data according to an embodiment of the present invention The schematic diagram which shows the example of the update map data which concerns on embodiment of this invention The schematic diagram which shows the example of the difference map data which concerns on embodiment of this invention The flowchart which shows the procedure of the map difference update process which concerns on embodiment of this invention The flowchart which shows the procedure of the map object identity determination process which concerns on embodiment of this invention The flowchart which shows the procedure of the evaluation value calculation process which concerns on embodiment of this invention The flowchart which shows the procedure of the difference map data extraction process which concerns on embodiment of this invention The flowchart which shows the procedure of the map data reading process which concerns on embodiment of this invention The schematic diagram which illustrates the flow of the data of the map difference update system which concerns on embodiment of this invention The schematic diagram which illustrates sharing of the update information in the map difference update system which concerns on embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Difference map data generation apparatus 2 Control part of difference map data generation apparatus 3 Input part of difference map data generation apparatus 4 Output part of difference map data generation apparatus 5 Map data storage part of difference map data generation apparatus 6 Difference map data generation apparatus Communication unit 7 Navigation device 8 Navigation device control unit 9 Navigation device input unit 10 Navigation device output unit 11 Navigation device map data storage unit

Claims (14)

  Update map data acquisition means for acquiring update map data including update information of map data, map object identity determination means for comparing the map data and the update map data, and determining the same object, and the map object A difference map data generation device comprising difference map data generation means for generating difference information that does not exist in the map data from the updated map data using the result of the same determination means.   The difference map data generation apparatus according to claim 1, wherein the updated map data acquisition unit acquires the updated map data by communication.   The difference map data generation device according to claim 1, wherein the map object identity determination unit compares objects using at least one of a position and a shape of the object.   The difference map data generation apparatus according to claim 3, wherein the map object identity determination means compares objects using attribute information of the object.   5. The difference map data generation apparatus according to claim 3, wherein the map object identity determination unit compares objects using a connection relationship between objects.   The update map data includes information on the vicinity of the update information, and the map object identity determination unit compares the objects using a connection relationship with the information on the vicinity. 5. The difference map data generation device according to any one of up to 5.   Update map data acquisition means for acquiring update map data including update information of map data, map object identity determination means for comparing the map data and the update map data, and determining the same object, and the map object Using the result of the same determination means, comprising: means for extracting difference information that does not exist in the map data from the updated map data; and map data updating means for combining the difference information with the map data. Map data update device.   The map data and the updated map data are compared to determine the same object, and using the result of the map object identity determining means, the difference information not existing in the map data is converted to the updated map data. A difference map data generation program for causing a computer to execute the difference map data extraction step for extracting the difference map data and a step for storing the difference map data.   A difference map data generation device; and a navigation device, wherein the difference map data generation device includes update map data acquisition means for acquiring update map data including update information of map data, the map data, and the update map data. Difference map data generation that generates difference information that does not exist in the map data from the updated map data by using the results of the map object identity determination means and the map object identity determination means to determine the same object Means for acquiring and displaying map data from the difference map data generating device, means for executing at least one of map display and route guidance using the map data A map difference update system characterized by comprising:   The navigation device compares the map data and the updated map data with updated map data acquisition means for acquiring updated map data including update information of map data from the difference map data generation device, and determines the same object. Using the results of the map object identity determination means to determine, the map object identity determination means, means for extracting difference information that does not exist in the map data from the updated map data, and combining the difference information with the map data The map difference update system according to claim 9, further comprising map data update means.   The map difference update system according to claim 9, wherein the difference map data generation device generates the updated map data by combining the generated difference map data with the original map in advance and outputs the updated map data.   The difference map data generation device and the navigation device exist for each map format of the map data, and the difference map data generation means of the difference map data generation device generates the difference map data according to the format. The map difference update system according to claim 9 or 10, wherein the map difference update system is characterized.   The map difference update system according to any one of claims 9 to 11, wherein the difference map data generation device is included in the navigation device.   The center having the updated map data, and the navigation device connected to the center via a network, the updated map data acquisition means of the navigation device requests the updated map data from the center, the center, The map difference update system according to any one of claims 9 to 12, wherein the requested update map data is transmitted to the navigation device.

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