JP5714137B2 - Map data structure, map data creation method, and in-vehicle information terminal device - Google Patents

Description

  The present invention relates to a map data structure, a map data creation method for creating map data having the map data structure, and an in-vehicle information terminal device using map data created by the map data creation method.

  In a terminal device that uses a conventional map data structure and map data having the map data structure, the name data that is common between meshes and layers of the name data included in the map data is collected as common name data, The data amount of the entire data is reduced (see, for example, Patent Document 1).

  On the other hand, the KIWI format is known as a format of map data used in the in-vehicle information terminal device (for example, see Non-Patent Document 1).

  Usually, since map data has a large amount of data, a space in which map data including a background and a road exists is divided to manage a certain piece of spatial data. Hereinafter, a region obtained by dividing the space into tiles within a predetermined range is also referred to as a mesh.

  In addition, in order to execute map display, route search, and the like at high speed, a method of thinning out map data according to a scale is known. In the following, thinning out map data according to the scale is also referred to as hierarchization.

  In the above KIWI format, map data including the background and road is divided into meshes and managed in a hierarchical manner.

JP 2004-126036 A

Kiwi-W Consortium, “Car Navigation System-Open Data Structure KIWI and its Utilization-”, Kyoritsu Publishing Co., Ltd., February 2003, p. 24-51

  In Patent Document 1, name information for the same road data included in each of a plurality of meshes and layers is integrated without overlapping, and the integrated name data is used as common name data to reduce the data amount. However, since the data structure of the common name data is not shown in Patent Document 1 and a spatial management form is not adopted, there is a problem in accessibility to desired data. That is, for example, in the case of obtaining desired plural name data, there is a possibility that the desired data may be scattered without being managed collectively in the common name data. If it is stored on the disk, disk access) may occur randomly, which may degrade the data access performance.

  On the other hand, in Non-Patent Document 1, data is managed from a spatial point of view such as a hierarchy and a mesh, so that access to desired data is high, but the same data is managed redundantly in a plurality of hierarchies. There is a problem with the problem of reducing the amount of data.

  In an in-vehicle information terminal device having various functions such as navigation, the processing capacity of a CPU (central processing unit) and the storage capacity of a storage device such as a magnetic disk for storing data are limited. Reduction of volume is a challenge.

  The present invention has been made to solve these problems, and provides a map data structure, a map data creation method, and an in-vehicle information terminal device capable of improving the efficiency of data access and reducing the amount of data. Objective.

In order to solve the above-described problem, the map data structure according to the present invention is a structure of map data included in each mesh of a plurality of layers, the map data in a mesh of a predetermined layer, and a lower level than the predetermined layer Among the map data in the mesh corresponding to the mesh of the predetermined hierarchy, the map data which is the predetermined map data and common to both is duplicated in the mesh of the predetermined hierarchy and the mesh of the lower hierarchy So that the common map data in each mesh of each of the plurality of hierarchies is managed as one data set, and the predetermined map data is name data indicating the name of a place on the map , or characterized by Oh Rukoto in the POI data indicating the point.

According to the present invention, there is a structure of map data included in each mesh of a plurality of layers, the map data in a mesh of a predetermined layer, and a mesh lower than the predetermined layer and in the mesh of the predetermined layer Among the map data in the corresponding mesh, the map data that is the predetermined map data and common to both is included in the mesh of the predetermined hierarchy so as not to overlap between the mesh of the predetermined hierarchy and the mesh of the lower hierarchy, each plurality of common map data in each mesh of the hierarchy are managed as a set one data, predetermined map data, because Ah in POI data indicating the name data or points, indicating the name of the location on the map, Data access efficiency can be improved and the amount of data can be reduced.

  Objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

It is a figure which shows an example of a structure of the map database by Embodiment 1 of this invention. It is a figure which shows an example of the display of the map data by Embodiment 1 of this invention. It is a figure which shows three-dimensionally an example of the hierarchy of the map data and mesh structure by Embodiment 1 of this invention. It is a figure which shows planarly an example of the hierarchy of the map data and mesh structure by Embodiment 1 of this invention. It is a figure which shows an example of a structure of the map data by Embodiment 1 of this invention. It is a figure which shows the map data structure in the mesh by Embodiment 1 of this invention. It is a figure which shows the detail of the map data structure shown in FIG. 6 by Embodiment 1 of this invention. It is a figure which shows the map data structure of the lowest layer in the map data structure shown in FIG. 7 by Embodiment 1 of this invention. It is a block diagram which shows an example of a structure of the map data creation apparatus by Embodiment 1 of this invention. It is a flowchart which shows the preparation process of the map data which has the map data structure by Embodiment 1 of this invention. It is a figure which shows an example of the hardware constitutions of the information processing apparatus by Embodiment 1 of this invention. It is a block diagram which shows the structure of the vehicle-mounted information terminal device by Embodiment 1 of this invention. It is a flowchart which shows the operation | movement in which the vehicle-mounted information terminal device by Embodiment 1 of this invention acquires desired map data from a map database. It is a figure which shows the map data structure in the mesh by Embodiment 2 of this invention. It is a figure which shows the detail of the map data structure shown in FIG. 14 by Embodiment 2 of this invention. It is a figure which shows the map data structure of the lowest layer in the map data structure by Embodiment 3 of this invention. It is a figure which shows the image of the data extraction process by the designation | designated data extraction means by Embodiment 1 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

<Embodiment 1>
FIG. 1 is a diagram showing an example of the configuration of the map database 8 according to Embodiment 1 of the present invention. As shown in FIG. 1, the map database 8 includes point (point) data that represents representative points of city names, place names, and polyline (line) data that represents lines such as rivers, bus routes, and contour lines. Geometric data 81 serving as a map background, such as polygonal (surface) data representing a closed space such as a house plan, a park, or a lake, is provided.

  The map database 8 includes nodes and links used for route search, such as a road network connecting intersections (nodes) and roads (links), and a railway network connecting stations (nodes) and routes (links). The phase data 82 is provided.

  In addition, the map database 8 includes name data 83 indicating the name of a place such as an administrative name (A city) and a road name (ABC street) in the geometric data 81 that is the background of the map, a restaurant, a convenience store, and a station. And POI (Point Of Interest) data 84 indicating the point data.

  In addition to the above, the map database 8 includes voice data for voice guidance of route search results, VICS (registered trademark) (Vehicle Information and Communication) indicating traffic conditions such as traffic congestion and road construction, and TMC (Traffic). Traffic information data such as Message Channel).

  The map database 8 including map data including the geometric data 81, the phase data 82, the name data 83, and the POI data 84 is stored in a storage device such as a hard disk drive (HDD: Hard Disk Drive) having a magnetic disk.

  FIG. 2 is a diagram showing an example of display of map data as shown in FIG.

  As shown in FIG. 2, geometric data 81, name data 83, POI data 84, and the like are mapped in association with position information such as latitude and longitude in a plane space (on a map shown in a plane). . Further, as shown in FIG. 2, the map database 8 shown in FIG. 1 is managed by dividing the map data for each mesh 9 obtained by dividing the plane space into tiles.

  FIG. 3 is a diagram three-dimensionally showing an example of the hierarchical structure and the mesh structure of the map data. In addition, in FIG. 3, it has shown about the map data of 3 layers.

  As shown in FIG. 3, a mesh 10 indicated by a solid line is used when a map is enlarged (large scale) and displayed. Further, the mesh 11 indicated by a broken line is used when displaying at a smaller scale than the mesh 10. Further, the mesh 12 indicated by a double line is used when displaying at a smaller scale than the mesh 11.

  Also, as shown in FIG. 3, in the first embodiment, the hierarchical number corresponding to the mesh 10 is level 1, the hierarchical number corresponding to the mesh 11 is level 2, and the hierarchical number corresponding to the mesh 12 is level 3. . Numbers 1 to 16 assigned to the meshes indicate that there are 16 level 1 meshes. The mesh 11 is composed of level 1 mesh numbers 1 to 4 (four meshes 10) as one unit. Similarly, the mesh 12 is composed of four meshes of level 2 as one unit. That is, the one higher hierarchy (hierarchy with a small one-stage scale) is configured by combining four meshes in one hierarchy lower than the hierarchy (a hierarchy with a large one-step scale). Therefore, for example, the mesh 12 is composed of 16 level 1 meshes (mesh numbers 1 to 16) including the mesh 10 and manages these areas (the management will be described later). ).

  FIG. 4 is a plan view showing an example of the hierarchical structure and mesh structure of the map data shown in FIG.

  In FIG. 4, as in FIG. 3, the mesh 10 indicated by a solid line is indicated as a level 1 mesh, the mesh 11 indicated by a broken line is indicated as a level 2 mesh, and the mesh 12 indicated by a double line is indicated by a level Shown as 3 meshes.

  As described above, the level 2 mesh 11 is configured by combining the four level 1 meshes (mesh numbers 1 to 4). Further, the level 3 mesh 12 is composed of an area composed of four level 2 meshes, and is also composed of an area composed of 16 level 1 meshes (mesh numbers 1 to 16). .

  In the first embodiment, the map data has been described as having three layers, but the above rule is applied even when there are more than three layers. For example, in the case where level 4 exists, the level 4 mesh is configured by an area obtained by combining four level 3 meshes.

  FIG. 5 is a diagram showing an example of the configuration of map data according to the first embodiment.

  In the present embodiment, as the map data, the name data 83 and the POI data 84 that are basically not thinned between layers are targeted.

  On the other hand, the other geometric data 81 and phase data 82 are designed to speed up map display and route search processing by thinning data between layers.

  For example, in the case of a polyline indicating a road line, when the map is large scale (at a large scale), for example, when the scale is such that the shape of the house can be identified, coordinate points indicating changes in the data shape are finely managed, A narrow area is displayed by expressing the actual road shape in detail. On the other hand, when the map is in a small scale (when the scale is small), for example, if it is a scale that displays the entire prefecture, it is only necessary to know the approximate shape of the road. Is unnecessary. Since map data in a wide area is required at a small scale, it is necessary to secure display performance by reducing the data amount of the map data. Therefore, the road shape obtained by thinning out the road shape at the time of large scale is separately managed. Similarly, for road networks, network information consisting of nodes and links is closely managed at a large scale, whereas at a small scale, the network information is thinned out to manage the route information. Network information processing such as search can be executed at high speed.

  Since the target name data 83 and POI data 84 in this embodiment are point data consisting of a single point, the position information is basically used in a plurality of layers without being thinned out. However, when the name and POI display may overlap at a small scale, it is necessary to shift the display position of the name and POI. In such a case, it is possible to manage the display position according to the scale by separately using attribute information or the like.

  As shown in FIG. 5, a mesh 10 indicated by a solid line is indicated as a level 1 mesh, a mesh 11 indicated by a broken line is indicated as a level 2 mesh, and a mesh 12 indicated by a double line is a level 3 mesh. Is shown as When the map data is configured in three layers as in the first embodiment, the level 3 mesh 12 includes four level 2 meshes, and the level 2 mesh 11 includes four level 1 meshes. Includes mesh.

  Further, the map data is collectively managed in four meshes for each level (each layer). In other words, four meshes at level 1 are managed in level 2 and four meshes at level 2 are managed in level 3 at level 3, respectively. The mesh order is usually arranged in ascending order of mesh number. For example, as shown in FIG. 4, the mesh number is assigned in a zigzag manner such as the lower left (1), the lower right (2), the upper left (3), and the upper right (4) as in the alphabet “Z”. is there. In FIG. 5, an ID for identifying each mesh is indicated by “level number−mesh number”. For example, the ID of mesh number 1 of level 1 as the lowest layer is indicated by “mesh 1-1”.

  Data in each mesh of each layer is stored as data used in a layer to which the mesh storing the data belongs (hereinafter also referred to as a target layer), and is temporarily managed in a layer higher than the layer. When data is used, it is collected and used. By doing so, it is possible to eliminate duplication of data between hierarchies and reduce the amount of map data. That is, for example, mesh data 16 having a mesh ID “mesh 2-1” is data that is not used at a higher level (for example, level 3). Also, for example, when there is data that is shared between level 1 and level 2, the data is stored as level 2 mesh data 16 on the upper layer side, and the data is used at level 1. Can acquire and use data corresponding to the level 1 mesh at level 2 from the level 2 mesh data 16. In FIG. 5, level 1 mesh data as the lowest layer is indicated by mesh data 17, and level 3 mesh data is indicated by mesh data 15.

  FIG. 6 is a diagram showing a map data structure in the mesh according to the first embodiment.

  As shown in FIG. 6, the map data according to the first embodiment includes a header part 21 and an actual data part 22. As described above, since data used in common in the target hierarchy and lower hierarchy is managed on the upper hierarchy side (that is, the target hierarchy), information on the lower hierarchy that uses the data is managed in the target hierarchy. There is a need.

  The header section 21 includes a lower layer number 23 indicating the number of layers lower than the target layer (including the target layer), and a lower layer number array 24 that manages the layer numbers of the lower layers.

  The header unit 21 includes N layer data information 30 for each lower layer, and the N layer data information 30 includes a lower layer mesh number 25 indicating the number of meshes included in each layer, and a mesh included in each layer. A lower layer mesh ID array 26 for arranging several IDs and a lower layer mesh offset array 27 indicating the position of the actual data in the actual data portion 22 corresponding to the mesh ID of the lower layer mesh ID array 26 are provided.

  The header section 21 includes a current layer mesh ID 28 indicating the ID of the mesh in the target layer and a current layer number 29 indicating the layer number of the target layer.

  The actual data part 22 stores various data. For example, the name data includes a display position, a character string, a name type (for example, whether the name indicates a road or an administrative name), and the like.

  FIG. 7 is a diagram showing details of the map data structure shown in FIG.

  As shown in FIG. 7, the N layer data information 30 corresponds to the lower layer numbers 31 and 32 stored in the lower layer number array 24. That is, the N layer data information 30 of the number designated by the lower layer number 23 exists in the map data structure. For example, when the map data is configured as shown in FIG. 5 and the current layer number 29 is “3” and the current layer mesh ID 28 is “3-1”, the actual data of level 3 that is the target layer is displayed. In the case of use at lower levels 2 and 1, the lower layer number 23 is “3” including level 3 as the target layer, and level 3, level 2 and level 1 are stored in the lower layer number array 24 as lower layer numbers. . For example, level 3 is stored in the lower layer number 31 and level 2 is stored in the lower layer number 32.

  Further, in the N layer data information 30, in the case of level 3, the number of N layer meshes 25 is “1”, the mesh ID 33 of the lower layer mesh ID array 26 is “3-1”, and the offset 35 of the lower layer mesh offset array 27 is actual. An index of mesh ID 33 in the actual data of the data part 22 is stored. Further, in the case of level 2, the number of meshes that share the actual data of level 3 also in level 2 (if the map data and the hierarchical structure of the map data are as shown in FIGS. Is stored in the N-layer mesh number 25, and each mesh ID is stored in the lower-layer mesh ID array 26. In the lower layer mesh offset array 27, an index indicating the storage position of the actual data 22 included in the mesh ID is stored in the offset (for example, the offset 35 of the mesh ID 33).

  That is, the map data structure according to the first embodiment is a structure of map data included in each mesh of a plurality of hierarchies, and the map data in a mesh of a predetermined hierarchy (target hierarchy) and lower than the predetermined hierarchy Among the map data in the mesh corresponding to the mesh of the predetermined hierarchy, the map data that is predetermined map data (for example, name data, POI data) and common to both is the mesh of the predetermined hierarchy It is included in a mesh of a predetermined hierarchy so as not to overlap with a mesh of a lower hierarchy, and common map data in each mesh of each of the plurality of hierarchies is managed as one data set. The mesh of a predetermined hierarchy (target hierarchy) has information (offset) indicating a data range corresponding to a mesh of a lower hierarchy with respect to common map data included in the mesh.

  Note that FIG. 7 shows an example of the map data structure, and information (for example, the number of actual data) for efficiently accessing the actual data may be provided in addition to the illustrated information.

  FIG. 8 is a diagram showing a map data structure in the lowest layer in the map data structure shown in FIG.

  As shown in FIG. 8, in the lowest layer, there is no lower layer than the layer, and therefore information on the lower layer is unnecessary. That is, when the lower layer number 23 is set to 0, a map data structure in which the lower layer number array 24 and the N layer data information 30 are omitted can be obtained.

  Next, means for creating a map data structure will be described.

  FIG. 9 is a block diagram showing an example of the configuration of the map data creation device 50 according to the first embodiment.

  As shown in FIG. 9, the map data input means 51 is a means for inputting original data that is map data that is the basis for creating the above-described map data structure.

  The map data dividing means 52 is means for dividing the map data input by the map data input means 51 into meshes (see, for example, FIG. 4).

  The map data hierarchizing means 53 is means for hierarchizing the map data input by the map data input means 51 (see, for example, FIG. 3).

  The designated data extraction unit 54 extracts predetermined designated data from the original data input by the map data input unit 51 and allocates the data to the hierarchies hierarchized by the map data hierarchization unit 53. Note that the designated data extraction unit 54 may refer to a rule as to which hierarchy data is allocated for each type of original data.

  The output data creation means 55 is means for creating the data of each hierarchy extracted and allocated by the designated data extraction means 54 in accordance with the above map data structure.

  The map data output means 56 is means for outputting the map data created by the output data creation means 55 to an external storage device such as a magnetic disk.

  FIG. 10 is a flowchart showing a process for creating map data having a map data structure according to the first embodiment.

  In step S1, the original data, which is the original map data (not shown) managed by an external storage device or the like for creating the map database 8 as shown in FIG. Read (input).

  Next, in step S2, it is determined whether or not the input map data is hierarchized. When hierarchizing (YES in step S2), the process proceeds to step S3, and when not hierarchizing (NO in step S2), the process proceeds to step S4.

  Next, in step S3, the map data layering means 53 performs layering as shown in FIG.

  Next, in step S4, the map data dividing means 52 divides the input original data into meshes as shown in FIG.

  Next, in step S5, the designated data extraction means 54 extracts data designated from the original data input in step S1, for example, name data or POI data that is the target data of the first embodiment. I do. At this time, the extraction target data to be extracted may be specified by a separate definition file (not shown) or the like, and the specified data extracting unit 54 may refer to the definition file.

  FIG. 17 is a diagram showing an image of data extraction processing by the designated data extraction means 54. As shown in FIG. 17, the original data included in the mesh is an image in which only necessary data in each layer is left and other data is screened down to the lower layer (data is filtered in each layer). Create data for each mesh.

  Next, in step S6, the output data creation means 55 performs processing for creating map data to be output according to the map data structure shown in FIG. 7 using the data specified and extracted in step S5.

  Next, in step S7, the map data output means 56 performs processing for outputting the output data (map data) created in step S6 to an external storage device such as a magnetic disk.

  Next, in step S8, it is determined whether or not map data has been created for all levels. If it is determined that map data has been created for all levels (YES in step S8), map data is determined. When it is determined that the map data has not been created for all layers (NO in step S8), the process returns to step S3 and the process is performed again.

  That is, the map data creation method according to the first embodiment is a map data creation method for creating map data having the above-described map data structure (for example, see FIG. 7), and (a) a step of inputting map data (B) hierarchizing the map data input in step (a) and dividing it into a plurality of meshes; (c) after step (b), a map in a mesh of a predetermined hierarchy (target hierarchy) Map that is predetermined map data (for example, name data, POI data) and common to both of the data and map data in a mesh that is lower than the predetermined hierarchy and corresponds to the mesh of the predetermined hierarchy A step of extracting data, and (d) the common map data extracted in step (c), the common map data is meshed in a predetermined hierarchy based on the map data structure A step of creating new map data by including in a mesh of a predetermined layer so as not to overlap with a mesh of a lower layer, and in the new map data created in step (d), The common data in each mesh of a hierarchy is managed as one data set.

  Next, an in-vehicle information terminal device equipped with map data having a map data structure created by the map data creation process shown in FIG. 10 will be described.

  FIG. 11 is a diagram illustrating an example of a hardware configuration of an information processing device included in the in-vehicle information terminal device according to the first embodiment. As the information processing apparatus provided in the in-vehicle information terminal device according to the first embodiment, for example, there is an in-vehicle information terminal such as a car navigation device, a mobile phone, or a PDA (Personal Digital Assistant).

  As shown in FIG. 11, the external storage device 7 stores a data access program, an application program, data used in application processing, and the like. The external storage device 7 can read and write data via a hard disk device (HDD) mounted on the information processing device, an external storage medium such as a CD or DVD that can be played back by a drive device, or a predetermined input / output interface. It can be constructed in a USB (Universal Serial Bus) memory or the like.

  The application program is a program for realizing various functions executed by the in-vehicle information terminal device according to the first embodiment. For example, the application program has a route guidance function, a map display function, or a route search function in the car navigation device. It is a program to realize.

  The data access program is a program for acquiring data necessary for executing the application program from a data set stored in the external storage device 7.

  The calculation result by the CPU 5 is output to the display device 3 via the bus and displayed on the screen. The display device 3 is a device that displays, for example, a map used for route guidance, and is realized by a liquid crystal display, a plasma display, or the like.

  The communication device 4 is a device that performs communication with an external device (not shown). For example, when the information processing device according to the first embodiment is a car navigation device, the communication device 4 receives a GPS signal or FM radio wave transmitted from a GPS (Global Positioning System) satellite and detects position information. It also functions as a position detection unit.

  The input device 2 is a device that accepts an operation input from the outside, and is realized by a keyboard, operation switches, a touch panel combined with the display device 3, or the like. For example, when the information processing device according to the first embodiment is a car navigation device, a route search condition or the like is input using the input device 2.

  FIG. 12 is a block diagram showing a configuration of the in-vehicle information terminal device 1 according to the first embodiment.

  As shown in FIG. 12, the in-vehicle information terminal device 1 includes an input device 2, a position detection unit 61 that detects position information related to the vehicle position, and a navigation function execution unit that executes functions related to navigation such as map display and route search. 63 and a data access unit 62 that performs data access to the map database 8 using a data access program.

  The input device 2 corresponds to the input device 2 of FIG.

  The position detection device 61 has a function of detecting position information by receiving GPS signals and FM radio waves transmitted from GPS satellites, and corresponds to the communication device 4 of FIG.

  The navigation function execution unit 63 executes various functions in the navigation process based on the map data acquired from the map database 8 and the current position detected by the position detection unit 61.

  The data access unit 62 accesses the map database 8 with reference to related information of data corresponding to the function executed by the navigation function execution unit 63, and acquires desired map data. For example, the CPU 5 of the information processing apparatus in FIG. 11 operates as the data access unit 62 by executing the data access program.

  That is, the in-vehicle information terminal device 1 according to the first embodiment is an in-vehicle information terminal device that executes a predetermined function using map data having the above-described map data structure (see, for example, FIG. 7), such as navigation. A navigation function execution unit 63 that executes a predetermined function; a data access unit 62 that accesses the map database 8 that stores map data to acquire predetermined map data used by the navigation function execution unit 63; It is characterized by having. In addition, a data range corresponding to a mesh in a lower hierarchy is included with respect to common map data (for example, name data, POI data) included in the mesh included in the mesh of a predetermined hierarchy (target hierarchy) of the map data. By using the information (offset) shown, the map data in the desired mesh in the lower hierarchy is directly accessed.

  Next, a process in which the in-vehicle information terminal device 1 according to the first embodiment acquires desired map data from the map database 8 having the above-described map data structure will be described.

  FIG. 13 is a flowchart illustrating an operation in which the data access unit 62 of the in-vehicle information terminal device 1 according to the first embodiment acquires desired map data from the map database 8. The data access unit 62 acquires desired data from the map database 8 using a data access program.

  In step S11, a data range required by the in-vehicle information terminal device 1 is set. For example, when the navigation function execution unit 63 performs map display, the data range set at this time is acquired on the display screen based on the screen resolution and display scale of the display device 3 by acquiring the current location by the position detection unit 51. It is calculated by calculating the area required for The calculated data range is set in the data access unit 62.

  Next, in step S12, the data hierarchy (level) required by the in-vehicle information terminal device 1 is set (that is, the hierarchy number of the lower layer number array 24 in FIG. 7 is set). The data hierarchy set at this time is calculated based on a display scale necessary for the navigation function execution unit 63 to display a map, for example, and the calculated data hierarchy is set in the data access unit 62.

  Next, in step S13, based on the data range set in step S11 and the data hierarchy set in step S12, a mesh ID in which necessary data is stored is calculated. As described above, the mesh is obtained by dividing the map data and is managed for each hierarchy. As a result, it is possible to uniquely identify the mesh corresponding to the target data range by giving the coordinate values of the data range, for example, the southeast coordinates (latitude, longitude) and the northeast coordinates (latitude, longitude). It becomes.

  Next, in step S14, data corresponding to the target mesh is acquired from the map database 8 based on the mesh ID calculated in step S13. Specifically, in the map data structure shown in FIG. 7, the current layer mesh ID 28 is compared with the mesh ID calculated in step S13, and if the mesh IDs are the same, the target mesh data 18 is acquired. If there are a plurality of meshes in step S13, the processes after step S14 are executed for the number of meshes.

  Next, in step S15, actual data 22 is acquired from the mesh data 15 acquired in step S14.

  By performing the above processing, data (map data) of the target hierarchy can be acquired.

  Next, processing when data used in the target hierarchy exists also in a hierarchy higher than the target hierarchy and data managed in the higher hierarchy is used also in the target hierarchy will be described. That is, as described above, since the data used in common in the target hierarchy and the hierarchy higher than the target hierarchy is managed in the higher hierarchy, the target hierarchy that is the lower hierarchy receives data from the higher hierarchy. It is necessary to acquire this, and the process will be described below.

  In step S16, it is determined whether or not data (upper layer data) is to be acquired from the upper layer (upper layer) of the target layer. The determination may be made separately using definition data. For example, the definition data shows the data distribution for each layer for each data type, and the data access unit 62 compares the data types of the data to be acquired while referring to the definition data, It may be determined whether or not to acquire data from. If it is determined in step S16 that upper layer data is acquired (YES in step S16), the process proceeds to step S17. If it is determined that upper layer data is not acquired (NO in step S16), the data acquisition process ends.

  Next, in step S17, an upper layer mesh ID is calculated based on the mesh ID that is the target of data acquisition in step S14 and the hierarchy set in step S12. As described above, in the map database 8, since the mesh ID is uniquely determined based on the data range and the hierarchy, the upper layer mesh ID can be calculated similarly.

  Next, in step S18, data corresponding to the upper layer mesh ID is acquired from the map database 8 based on the upper layer mesh ID calculated in step S17. As for the acquisition method, as in step S14, in the map data structure shown in FIG. 7, the present layer mesh ID 28 is compared with the upper layer mesh ID calculated in step S18. The mesh data 18 is acquired.

  Next, in step S19, the Nth lower layer data information (N layer data information 30) is specified based on the hierarchy number set in step S12, and the step is performed from the lower layer mesh ID array 26 of the specified N layer data information 30. A mesh ID corresponding to the mesh ID calculated in S <b> 14 is found, and an offset indicating a data range corresponding to the found mesh ID is acquired from the lower layer mesh offset array 27.

  Next, in step S20, based on the offset acquired in step S19, mesh ID data corresponding to the mesh ID found in step S19 is acquired from the actual data.

  Next, in step S21, it is determined whether or not all upper layer data has been acquired. If it is determined that the data has been acquired (YES in step S21), the data acquisition process is terminated and it is determined that the data has not been acquired. In the case (NO in step S21), the process returns to step S17 to acquire the upper layer data again.

  As described above, according to the first embodiment, data common to each layer is managed by the upper layer, so that duplication of map data can be eliminated and the amount of data can be reduced. In addition, by managing the map data in each mesh of each layer as one data set, data management becomes easy, and desired data can be accessed at high speed, thereby improving data access efficiency.

  Further, according to the in-vehicle information terminal device according to the first embodiment, by using the map data having the map data structure according to the first embodiment, processing in the in-vehicle information terminal device such as navigation, route search, or map display is performed. It can be executed at high speed. Moreover, the data amount of the map data which occupies storage devices, such as HDD which stores the map database with which a vehicle-mounted information terminal device is equipped, can be made small.

  In addition, by managing the data common to each layer in the upper layer and providing an offset indicating the data position corresponding to the mesh range in the lower layer in the map data structure of the upper layer, it is common in the lower layer When using this data, the efficiency of access to desired data is improved.

<Embodiment 2>
In the first embodiment, as shown in FIGS. 6 and 7, the mesh data range corresponding to each lower layer (lower layer) than a certain layer is indicated by an offset. However, in the second embodiment, FIGS. As shown in FIG. 4, when actual data is created in the lowest layer and the actual data is used in an upper layer (upper layer), the mesh ID data 39 and a use layer indicating a layer using the actual data 40 may be managed as a set.

  From the above, according to the second embodiment, the lower layer number 23, the lower layer number array 24, and the N layer data information 30 as shown in FIG. As a result, the effect of reducing the data amount is obtained.

<Embodiment 3>
In the first embodiment, as shown in FIG. 8, the lowermost layer has a header part for managing data related to the lower layer, but the lowermost layer does not require an offset, and the hierarchical numbers are all the same. A hierarchy change flag 41 as shown in FIG. 16 may be provided, and the hierarchy number 29 may be set only when the hierarchy change flag 41 changes.

  From the above, according to the third embodiment, it is possible to obtain an effect that data in the header portion is reduced and the data amount is reduced.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention.

  1 in-vehicle information terminal device, 2 input device, 3 display device, 4 communication device, 5 CPU, 6 memory, 7 external storage device, 8 map database, 9 mesh, 10 mesh, 11 mesh, 12 mesh, 15 mesh data, 16 Mesh data, 17 mesh data, 18 mesh data, 21 header part, 22 actual data part, 23 lower layer number, 24 lower layer number array, 25 lower layer mesh number, 26 lower layer mesh ID array, 27 lower layer mesh offset array, 28 current layer mesh ID, 29 Current layer number, 30 N layer data information, 31 Lower layer number, 32 Lower layer number, 33 Mesh ID, 34 Mesh ID, 35 Offset, 36 Offset, 37 Mesh ID data, 38 Mesh ID data, 39 Current mesh ID data , 40 Hierarchy, 41 hierarchy change flag, 50 map data creation device, 51 map data input means, 52 map data division means, 53 map data hierarchization means, 54 specified data extraction means, 55 output data creation means, 56 map data output means 61 Position detection unit 62 Data access unit 63 Navigation function execution unit 81 Geometric data 82 Phase data 83 Name data 84 POI data

Claims (8)

A structure of map data included in each mesh of a plurality of layers,
Of the map data in the mesh of the predetermined hierarchy and the map data in the mesh lower than the predetermined hierarchy and corresponding to the mesh of the predetermined hierarchy, the map data is the predetermined map data and common to both Is included in the mesh of the predetermined layer so as not to overlap between the mesh of the predetermined layer and the mesh of the lower layer,
The common map data in each mesh of each of the plurality of layers is managed as one data set ,
The predetermined map data is characterized Oh Rukoto in POI data indicating the name data or points, indicating the name of the location on the map, map data structure.   The mesh of the predetermined hierarchy has information indicating a data range corresponding to the mesh of the lower hierarchy with respect to the common map data included in the mesh. Map data structure. The map data is managed in a group of four meshes for each of the layers, and each of the four meshes is arranged in ascending order of mesh numbers assigned to the four meshes. The map data structure according to claim 1, wherein the map data structure is characterized. The map data in the mesh of the predetermined hierarchy is
  A header portion having a lower layer number indicating the number of layers lower than the predetermined layer, and a lower layer number array for managing a layer number of the lower layer;
  An actual data part having actual data of the common map data;
The map data structure according to claim 1, comprising: A map data creation method for creating map data having the map data structure according to claim 1,
  (A) inputting map data;
  (B) hierarchizing the map data input in the step (a) and dividing it into a plurality of meshes;
  (C) After the step (b), a predetermined level of map data in a mesh of a predetermined hierarchy and map data in a mesh lower than the predetermined hierarchy and corresponding to the mesh of the predetermined hierarchy Extracting map data that is common to both, and
  (D) For the common map data extracted in step (c), based on the map data structure, the common map data does not overlap between the mesh of the predetermined hierarchy and the mesh of the lower hierarchy Creating new map data by including it in the mesh of the predetermined hierarchy,
With
  In the new map data created in the step (d), the common map data in each mesh of each of the plurality of hierarchies is managed as one data set. Method. The mesh of the predetermined hierarchy of the new map data created in the step (d) indicates a data range corresponding to the mesh of the lower hierarchy with respect to the common map data included in the mesh. It has information, The map data creation method of Claim 5 characterized by the above-mentioned. An in-vehicle information terminal device (1) that executes a predetermined function using map data having the map data structure according to claim 1,
A navigation function execution unit (63) for executing the predetermined function such as navigation;
A data access unit (62) for accessing the map database (8) for storing the map data in order to obtain the predetermined map data used in the navigation function execution unit (63);
An in-vehicle information terminal device comprising:   By using information indicating a data range corresponding to the mesh of the lower hierarchy for the common map data included in the mesh of the mesh of the predetermined hierarchy of the map data, 8. The in-vehicle information terminal device according to claim 7, wherein the map data in a desired mesh is directly accessed.

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