JP3332225B2 - Map providing system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a terminal device,
More specifically, the present invention relates to a terminal device in which a map file in which each unit obtained by dividing a map into a plurality of regions is converted into digital data is stored in an internal storage device and reads the map file from the storage device.

[0002]

2. Description of the Related Art In recent years, vehicles equipped with a navigation system have been increasing. In the navigation system, initially, only a file for creating a map on a screen (hereinafter, referred to as a map file) was provided. However, in recent years, in addition to map files,
For example, traffic information and route guidance information have also been provided. Such diversification of information makes navigation systems more convenient and is expected to spread rapidly in the future.

[0003] Initially, navigation systems include CDs
-A storage device having a read-only recording medium represented by a ROM was mounted. In this recording medium, a map file to be provided to the user and its related data are recorded in advance. The storage device reads the map file recorded on the storage medium as needed. The read map file has been referred to by a user or used for a route search process or a map matching process.

In general, a digital map file is created for each rectangular area obtained by dividing each map at equal intervals in the longitude and latitude directions in order to efficiently manage the hierarchical structure of maps having different scales. Hereinafter, in the “first related art”, such a rectangular area is hereinafter referred to as a unit.

[0005] Such a map file is typically used for a route search process or a current position correction process (map matching) in a car navigation system. For this purpose, road map data is recorded in the map file. The road network data includes at least connection information indicating a connection relationship between each node and each link. Here, the node is mainly information indicating an intersection existing in a road network, and the link is mainly vector information indicating a road existing between two intersections. A map representing the road network in each unit is represented by a set of such nodes and links.

Although the minimum road network can be represented by the above-mentioned nodes, links and their connection information, this alone is not sufficient for displaying a map. For example, roads between intersections are often bent on roads in mountainous areas and seaside areas. Therefore, the road network data further includes information for specifying a link shape to display the shape of the curved road. As is clear from the above, links are often represented by vector data. There are various types of roads such as national roads and prefectural roads. In addition, roads can be classified according to the difference in the number of lanes or the presence or absence of a median strip. In order to distinguish the type of road, the road network data further includes attribute information indicating the type of road and the like.
In addition, some intersections have an intersection name and some have no intersection name. Furthermore, there are intersections where traffic lights are installed and intersections where traffic lights are not installed. Therefore, the road network data
Each node has attribute information. Information such as the name of the corresponding intersection and the presence or absence of a traffic light is recorded in each attribute information.

[0007] In a map file having a vector data structure, when a road extending over a plurality of units exists, a special node (hereinafter, referred to as an adjacent node) is separately created at the boundary of the unit. By passing through such an adjacent node, it is possible to trace a road connection relationship between units adjacent to each other. In a conventional map file, the adjacent nodes of a unit are
An offset address and a record number have been recorded in order to specify which adjacent node of the adjacent unit corresponds to. Here, the offset address indicates at which address position the adjacent node is recorded with respect to the reference address. The record number indicates in which position in the map file of the adjacent unit the adjacent node is recorded starting from the first node.

[0008] As described in "Second prior art" and "First prior art", the conventional navigation system can only use a map file recorded on a read-only recording medium at first. It was difficult to provide highly reliable information. As such information having a high real-time property, traffic information or weather information is representative. Therefore, information that requires real-time properties,
Further, a map providing system capable of providing a map file is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 7-262493. In the map providing system of this publication, a map file and information having high real-time properties are downloaded from an information providing center to a terminal device mounted on a vehicle via a communication medium.

The map providing system is constructed based on mobile communication technology and digital broadcasting technology in order to provide information in real time. In such a map providing system, the center station distributes information to a mobile object existing in the service area using a predetermined broadcast channel. As a center station, a communication satellite (so-called C
S), a broadcasting satellite (so-called BS), or a terrestrial digital broadcasting station is typical. A map providing system using the mobile communication technology and the digital broadcasting technology is disclosed, for example, in Japanese Patent Laid-Open No. 7-154350. More specifically, this gazette discloses a technical content for limiting a broadcasting area of certain information. That is, when transmitting the multiplexed information via the broadcast media, the center station attaches an area code such as a postal code to each piece of information. The terminal device pre-registers the area code corresponding to its current position as an ID in the memory. Inside the terminal device, a data extraction circuit separates multiplexed information broadcast from a broadcasting station and extracts a region code added to each information. Further, inside the terminal device, the extracted area code is compared with the registered ID. If the two match, the terminal device allows the user to refer to the information with the target area code.

[0010] As described above, the development of a map providing system for providing a map by communication or broadcasting has been actively developed in recent years. In this map providing system, the center station reads out a map file to be transmitted to the terminal device in units and transmits the map file to the terminal device. After receiving the map data from the center station, the terminal device stores the map data in the storage device. The stored map file is used by the user for reference, route search processing, or map matching processing as needed.

[0011]

[Problems to be Solved by the First Related Art] As is apparent from the first related art, conventionally, a map file of a certain unit contains data in the map file of an adjacent unit. Information directly indicating the structure (the offset address or record number described above) has been recorded. For example, when a road in a certain unit is newly constructed, the map file of the unit is naturally updated. In the updated map file, the position where the adjacent node is recorded often changes. Therefore, if a method of instructing a conventional map file internal data structures such as direct <br/> adopted, from the adjacent node recorded in the map file of the adjacent unit, adjacent corresponding in the updated map file You no longer trace nodes exactly. That is,
When a certain map file is updated, there is a problem that the map file of an adjacent unit often needs to be updated.

As a measure for evaluating the quality of the digital map file, there is a map detail level. However, in a map file, since links are represented by vector data, there is a problem that the more the detailed map is represented, the larger the data amount of the map file becomes. Conventionally, such map files are mainly used in car navigation systems. In car navigation systems, CD-ROM, DVD
-A map file is recorded on a large-capacity storage medium such as a ROM or a hard disk. However, in the future, it is conceivable that the map file will be used not only in a car navigation system but also in an information device that can be carried by a person. It is difficult to mount a large-capacity storage medium such as a car navigation system in such a portable information device. From this point, it is highly necessary to compress the data amount of the map file.

[0013] By the way, each of the publications described in the column of "Second Conventional Technology" discloses nothing about how a terminal device stores a map file in a storage device. Not. It is easy to imagine that the terminal device creates a map file for each received unit,
This is a method of storing the created map file in a storage device. However, this method has a problem that the use efficiency of the storage area is deteriorated. Now, for example, it is assumed that a map β representing a certain range is partitioned into 64 rectangular units as shown in FIG. Further assume that the terminal receives and stores four units 71-74. Further, as is well known, the storage area of the storage device is managed in cluster units. Further, the data size of each unit does not always match the integral multiple of the cluster size. Therefore, the terminal device transmits four files 81 to 84 for the four received units 71 to 74.
, Four clusters 91 to 94 having an empty area often occur as shown in FIG. FIG.
In FIG. 2, the portions with dots are the files 81
To 84 indicate recorded areas. The hatched portion indicates a free area. The free space generated in each of the clusters 91 to 94 is not used. That is, even if the terminal device is a unit 75 (see FIG. 71) other than the units 71 to 74.
Even if the file 75 is received, the file created based on the unit 75 is not stored in the free area of each of the clusters 91 to 94. As is clear from the above, as the number of units received by the terminal device increases, the number of clusters having an empty area increases. That is, the use efficiency of the storage area is deteriorated.

By the way, if the map is divided into a relatively small number of units, it is possible to make it difficult to generate a cluster having an empty area. Now, map β in the same range as FIG.
Is partitioned into 16 rectangular units as shown in FIG. The range represented by the unit 76 in FIG. 73 is
This corresponds to the combined range of units 71 to 74 in FIG.
Further assume that the terminal receives and stores one unit 76. Under this assumption, when the terminal device creates one file 86 for one received unit 76, only one cluster 96 having an empty area is generated as shown in FIG. The dot portion in FIG. 74 indicates an area where the file 86 is recorded. The hatched portion indicates a free area.

As is clear from the above, when the map is divided into small units (see FIG. 71), if a map file representing a certain range is stored in the storage device, a relatively large amount of free space is generated (see FIG. 71). See FIG. 72). However,
When the map is divided into large units (see FIG. 73), even if map data in the same range is stored in the storage device, the generated free area is small (see FIG. 74). That is, from the viewpoint of effective use of the storage area, it is better that the map is divided into a small number of units.

However, dividing the map into a small number of units means that the data amount per unit becomes large. Therefore, the base station must transmit a large amount of data to the terminal device at one time. As a result, the wireless transmission path is likely to fall into a congested state,
In other words, another problem arises in that the use efficiency of the wireless transmission path deteriorates. That is, there is a problem that if the storage area is emphasized, it is difficult to efficiently use the wireless transmission path, and if the wireless transmission path is emphasized, it is difficult to efficiently use the storage area.

[0017] Therefore, a first object of the present invention is to provide a data structure of a map file which does not require updating of a map file of an adjacent unit when a certain one is updated. It is a second object of the present invention to provide a data structure of a map file which can compress the data amount. A third object of the present invention is to provide a map providing system capable of efficiently using a storage area in a terminal device and efficiently using a transmission path between a center station and the terminal device. is there.

According to the present invention, there is provided a system in which a center station provides a map file to a terminal device through a transmission line, wherein the center station has a first storage device for storing a map file representing a map of a predetermined range. And a read control unit for reading a part or all of the map file as map data from the first storage device, and assembling a packet in a format suitable for the transmission path using the map data read by the read control unit. A packet assembling unit, and a transmitting unit that transmits the packet assembled by the packet assembling unit to the terminal device via the transmission path, wherein the terminal device receives, via the transmission path, the packet transmitted by the transmitting unit; A data processing unit that performs processing for decomposing a packet received by the receiving unit and restoring map data, A second storage device for storing the map file in the storage medium of the unit, wherein the data processing unit is configured to store the map file related to the map data restored this time when the map file is already stored in the second storage device. , the read second the map file from the storage device, further, the restored map data, in addition to read mAP file, that stores in the second storage device.

In the above invention, the data processing section restores the current time.
Map data and the location read from the second storage device.
The figure files are grouped together and stored in the second storage device.
And thereby update the map file. This
As described above, the data processing unit processes the map data received by the receiving unit.
Do not create a map file based on the Data processing unit
Is the map data received this time,
Add to figure file. Therefore, the second storage device:
Without storing many map files with small data volume
Stores a map file with a large amount of data.
Clusters having an active region are less likely to occur. This
A map that can efficiently use the storage area on the terminal device side
A providing system can be realized.

Further, in the above invention, the center station is small.
Even if the map data of the size is transmitted, the terminal
Combine map data provided by
It is possible to suppress the occurrence of clusters having free space.
Wear. Thus, in the thirty-fifth aspect, the center station is small.
Congestion in the transmission path
It becomes difficult to fall into a state. This makes the transmission path more efficient
A map providing system that can be used
You.

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment "System Configuration" FIG. 1 is a block diagram showing the configuration of a map providing system according to one embodiment of the present invention. In FIG. 1, a terminal device 1 and a center station 2 are accommodated in the map providing system. The terminal device 1 and the center station 2 are connected via a communication network 3 so as to be capable of two-way communication. More specifically, an uplink UL and a downlink DL are provided between the terminal device 1 and the center station 2. The uplink UL means a communication path from the terminal device 1 to the center station 2, and the downlink DL means a communication path from the center station 2 to the terminal device 1.
Means a communication path to Here, a typical example of the communication network 3 is a mobile communication network represented by a mobile phone, an ISDN.
(Integrated ServicesDigit
al Network), or a public line or a dedicated line. Further, the communication network 3 may be configured by any two or more of a mobile communication network, a public line, and a dedicated line.

Next, the configuration of the terminal device 1 will be described. The terminal device 1 typically corresponds to a car navigation system, and includes an input device 11 and a position detection device 1.
2, a data processing unit 13, a request generation unit 14, a first transmission / reception unit 15, an antenna 16, a packet disassembly unit 17
, A read / write control unit 18, a first storage device 19, and an output device 110. The input device 11
It is realized in hardware by a remote controller for remotely operating the car navigation system or by keys arranged on the car navigation system body, or in software by buttons displayed on a menu screen of the car navigation system. Further, the input device 11 may be realized by making full use of voice recognition technology. The user of the terminal device 1 operates the input device 11 to perform various operations on the terminal device 1 such as scrolling or changing the scale of the displayed map, searching for a route, searching for information, or connecting to the center station 2. Request for proper processing. Further, the input device 11 outputs information for specifying the map file CF required by the user to the data processing unit 13 as a characteristic operation.

The position detecting device 12 is a speed sensor, a gyro sensor, or a GPS (Global Position).
oning System) and a receiver. In addition, speed sensor, gyro sensor,
And GPS (Global Positionin)
g System), the position detection device 12 may be realized by a combination of any two or more of the antenna and the receiver. The position detection device 12 detects the moving speed of the terminal device 1 by using a speed sensor, calculates the traveling distance based on the detection result, detects the traveling direction of the terminal device 1 by using a gyro sensor, and uses an antenna and a receiver. To receive the radio wave from the artificial satellite to detect the absolute position of the terminal device 1 on the earth. Based on the above detection results, the position detection device 12 detects the current position of the terminal device 1. The data processing unit 13 performs various data processing described later. One of the processes of the data processing unit 13 is a process of obtaining coordinates specifying a map range required by the user based on information input from the input device 11 and outputting the coordinates to the request generation unit 14. . When the coordinate information is input, the request generation unit 14 generates a map file C required by the user.
A control command for requesting the center station 2 to transmit F is generated. Thereafter, the generated control command is requested REQ
Shall be referred to as The request REQ has a predetermined format, and includes at least the coordinate information input to the request generation unit 14. Request REQ as above
Is output to the first transmission / reception unit 15. The first transmitting / receiving unit 15 is typically realized by a mobile communication device represented by a mobile phone. The first transmission / reception unit 15 sends the input request REQ to the uplink UL via the antenna 16.

The request REQ is received by the center station 2 via the uplink UL. The center station 2 analyzes the request REQ and outputs the map file C required by the user.
Specify F. The center station 2 uses the specified map file C
F is retrieved from the second storage device 24, and a plurality of packets P are assembled (assembled). The assembled packets P are sequentially transmitted to the terminal device 1 through the communication network 3 (downlink DL). The processing of the center station 2 will be described later in detail. In the terminal device 1, the first transmitting / receiving unit 15 further receives the packet P via the antenna 16 and outputs the packet P to the packet decomposing unit 17. The packet decomposing unit 17 decomposes (deassembles) the input packet P into the original map file CF, and outputs it to the data processing unit 13. When the map file CF is input, the data processing unit 13 executes a predetermined process, and when a predetermined condition is satisfied, creates the first database 111 based on the input map file CF. Output to the read / write control unit 18. The read / write control unit 18 writes the input map file CF as it is in the first storage device 19, or rewrites it with an existing map file CF. Note that a series of writing processes will be described later. The first storage device 19 is typically a data rewritable storage device represented by a hard disk drive or a flash memory. The first database 111 is stored in the first storage device 19. The first database 111
This is an aggregate of data including at least one map file CF necessary for the terminal device 1 to function as a navigation system. Also, the output device 110
Typically consists of a display and a speaker. On the display, the map represented by the map file CF is displayed together with the current position, or the result of the route search processing or the result of the route guidance processing by the data processing unit 13 is displayed. The speaker is a data processing unit 13
Is provided to the user by voice.

The data processing section 13 performs various processes using the map file CF constituting the first database 111. For example, the data processing unit 13 performs a process of displaying the current position of the terminal device 1. In this case, the data processing unit 13 needs a map around the current position detected by the position detection device 12, and thus cooperates with the read / write control unit 18 to make the first database 111
And retrieves and retrieves a map file CF representing the map. The data processing unit 13 performs a position correction process such as map matching using the extracted map file CF. After the position correction processing, the data processing unit 13 superimposes a pointer visually indicating the detected current position on the map represented by the extracted map file CF, and
Output to 0. In addition, the data processing unit 13 includes the terminal device 1
When the user requests route search processing or the like using the input device 11, the map file CF representing the map near the departure point and the destination and the map file CF representing the map including the route to be searched are read out. It is necessary to perform route search processing and the like. Also in this case, the data processing unit 13 searches and extracts the map file CF necessary for the route search processing and the like from the first database 111 in cooperation with the read / write control unit 18. The process of reading out a series of map files CF will be described later.

Next, the configuration of the center station 2 will be described. The center station 2 includes a second transmission / reception unit 21, a reception request analysis unit 22, a read control unit 23, a second storage device 2,
4 and a packet assembling unit 25. As described above, the request REQ generated by the terminal device 1 is transmitted to the center station 2 through the communication network 3 (uplink UL). The second transmission / reception unit 21 typically includes a communication device represented by a modem, a terminal adapter, or a gateway. Here, the gateway means that the center station 2 is connected to the communication network 3 using a different communication protocol.
Not only means a device or a function for connecting to the center station 2 but also means a device or a function for preventing another station from illegally accessing the center station 2. The second transmission / reception unit 21 is connected to the communication network 3 and controls data reception from the terminal device 1 and data transmission to the terminal device 1. More specifically, as one of the functions, the second transmission / reception unit 21 receives the request REQ transmitted via the uplink UL and outputs the request REQ to the reception request analysis unit 22.

The reception request analyzer 22 receives the input request R
The EQ is analyzed, and the analysis result is output to the reading control unit 23. The read control unit 23 reads a map file CF required by the terminal device 1 from the second storage device 24 based on the input analysis result. Here, the second storage device 2
4 is typically a hard disk drive, CD-R
It is composed of an OM drive or a DVD-ROM drive, and includes at least a recording medium from which stored data can be read and a driver for the recording medium. The second storage device 24 stores a second database 25. The second database 25 is an aggregate of data including at least one map file CF necessary for the center station 2 to function as a station that provides a map to the terminal device 1. That is, the map file CF refers to digital data representing a map that can be provided to the terminal device 1. The first database 111 of the terminal device 1 is created from the map file CF provided by the center station 2. Here, the read control unit 23 may read all of the map file CF, or may read out the map file CF.
It may be part of F. The read control unit 23 stores the read map file CF in the packet assembling unit 25.
Output to The packet assembling unit 25 assembles (assembles) the packet P based on the input map file CF and outputs the packet P to the second transmitting / receiving unit 21. The second transmission / reception unit 21 transmits the input packet P to the terminal device 1 via the downlink DL.

The overall configuration of the map providing system according to the present embodiment and the configurations of the terminal device 1 and the center station 2 have been described above. Next, the hierarchical structure and file name of the above-described map file CF will be described in detail.

[Hierarchical Structure and File Name] FIG. 2 is a diagram for explaining the hierarchical structure of the map represented by the map file CF according to the present embodiment. As shown in FIG. 2, first, a plurality of types of maps having different scales are prepared. In the present embodiment, for convenience, it is assumed that a map with four scales is prepared. In the following description, the maximum scale is referred to as level “0”, the second largest scale is referred to as level “1”, the third largest scale is referred to as level “2”, and the minimum scale is referred to as level “3”. As can be seen from the above, the map data has a maximum scale of level “0” and a level of “0” to “0”.
It is composed of four layers of “3”. Further, a map having a higher level is referred to as a map of a higher hierarchy, and a map having a lower level is referred to as a map of a lower hierarchy. Therefore, as shown in FIG.
The higher the level of the map, the wider the area and the lower the degree of detail. vice versa,
The lower-level map has a narrower area and a higher degree of detail. Also,
The map of each layer is divided at equal intervals along the longitude and latitude directions.

FIG. 3 is a diagram for explaining the unit of the highest hierarchy (level "3"). The world map of FIG. 3 is sectioned at intervals of 5 degrees and 20 minutes along the latitude direction with reference to latitude 0 degrees. Furthermore, this world map is based on 0 degree longitude, and is approximately 8 points along the longitude direction.
Delimited by degrees. As a result, the world map is about 640k
It is divided into rectangular areas of m squares. In the highest hierarchy (level "3"), a rectangular area of about 640 km square is called a unit. At level "3", about 6
One map file CF is created by converting 40 km square units into digital data. The unit U ₃ (hatched portion) will be described as a representative of the unit at the highest hierarchy (level “3”) as described above. Unit U at the highest level (level "3")
₃ is a unit including the Kansai area of Japan, latitude 0 degrees,
With the position at 0 degree longitude as the origin, it is located at the 16th position in the east longitude and the 6th position in the north latitude direction (however, units including the origin are counted as 0th). Unit U above
₃ is shown at the top of FIG.

As shown in FIG. 2, the map of the unit U ₃ is divided every 40 minutes along the latitude direction, as indicated by a dotted line, based on one vertex. Additionally, map unit U _3, based on the same vertex as described above, as shown by the dotted line is divided every one degree along the longitudinal direction.
As a result, the map of the unit U ₃ is 64 divided into rectangular areas of approximately 80km square. A map representing each rectangular area of about 80 km square in detail is one unit one layer lower (that is, the level “2” level). The unit U ₂ (hatched portion) will be described as a representative of the unit of the level “2”. The unit U ₂ is located at the fourth vertex in the east longitude and the first vertex in the north latitude with the position of one vertex (the lower left vertex for convenience) in the unit U ₃ as the origin (however, Unit U including the origin is counted as 0). Unit U ₂ hierarchy level "2" is shown in the second row of FIG.

Similarly, the map of the unit U ₂ is divided every 5 minutes along the latitude direction and every 7 minutes 30 seconds along the longitude direction with respect to one vertex, and as a result, about 10 km It is divided into 64 rectangular areas. About 10km
A map showing each of the four rectangular areas in detail is one unit one level lower (that is, the level “1” level). One of them, unit U ₁ (hatched portion), is located at the fifth point in the east longitude and the third in the north latitude, with the origin at the lower left vertex of unit U ₂ (however, , The unit including the origin is counted as 0). Unit U ₁ at the level "1" is shown in the third row from the top in FIG. 2.

Similarly, the map of the unit U ₁ is about 1.2
It is divided into 64 rectangular regions every km. About 1.2km
Each map showing the four directions in detail becomes one unit U one level lower (that is, the level “ 0 ” level). One of them, unit U ₀ (hatched portion), is located at the second point in the east longitude and the first in the north latitude with the origin at the lower left vertex of unit U ₁ (however,
The unit including the origin is counted as 0). Level "0"
Units U ₀ of is shown in the fourth stage from the top in FIG. 2.

FIG. 4 is a diagram for explaining the parent-child relationship of the unit U between the levels "3" to "0". First, in the following description, the child unit C
U means all units in the lower hierarchy included in the range covered by one unit U. In other words, the child unit CU is a set of units U representing a part of the map represented by one unit U in the upper hierarchy. Conversely, the parent unit PU means all units in the upper hierarchy including the range covered by a certain unit U. In other words, the parent unit PU is a set of units U including a map represented by one unit U in a lower hierarchy as a part of the map represented by itself. Here, the unit U ₃ in FIG. 4 is the unit U shown in FIG.
_It is equivalent to ₃ and is one of the units of level "3". A unit U of level “2” having unit U ₃ as a parent unit PU ₃ , that is, a unit belonging to level “2” among child units CU of unit U ₃ is a unit U _3
3 is divided into eight equal parts in the longitude and latitude directions, respectively.
There are four units U.

Thus, for the parent unit PU,
There are 64 child units CU one layer below. Each child unit CU is assigned a position code. The position code is information for specifying which part of the parent unit PU corresponds to the map represented by the child unit CU. In other words, the position code is information for specifying the position of the child unit CU with respect to the parent unit PU. Now, the parent unit PU is assumed to be 4 units U _3. In such a case, the lower left corner of the map detail children that represent unit CU of the unit U _3, "000 as a position code
"0" is assigned. Using the position code “0000” as a reference value, the child unit CU (position code “000”
0 ")," 0100 "is assigned to the child unit CU adjacent in the east longitude direction. Similarly,
Each time the child unit CU moves one in the east longitude direction, the position code increases by “0100”. With the position code “0000” as a reference value, “0001” is assigned to the child unit CU adjacent to the child unit CU (position code “0000”) along the north latitude.
Similarly, each time the child unit CU moves one position in the north latitude direction, the position code increases by “0001”. According to the position code assigned as described above, the unit U
Position code of the unit U ₂ which is one of the ₃ child unit CU is "0401".

Next, assume that the parent unit PU is a unit U _2. Also for this unit U _2, the lower layer (level "1") can 64 child unit CU. As shown in FIG. 4, a position code is assigned to the 64 child units CU of level “1” in the same manner as described above. For example, the position code of the unit U ₁ is one of child unit CU of the unit U ₂ is "050
3 ". Unit U as parent unit PU
_{Even for 1} , there are 64 child units CU one layer below (level "0"). As shown in FIG. 4, a position code is similarly assigned to each child unit CU of level “0”. For example, the position code of the unit U ₀ is one of child unit CU of the unit U ₁ is "02
01 ".

As described above, in the position code according to the present embodiment, the increment of the value in the east longitude direction and the increment of the value in the north latitude direction are predetermined. Therefore, child unit CU
It is possible to easily grasp the adjacent relationship between each other.

A file system is mounted on each of the terminal device 1 and the center station 2 shown in FIG. The file system on the terminal device 1 side includes a data processing unit 13 and a read / write control unit 18. In order to easily manage the first database 111 in the first storage device 19, the file system on the side of the terminal device 1 divides the recording area of the first storage device 19 into several logical areas called "directories". Divided into Further, the file system on the terminal device 1 side indicates the parent-child relationship and the adjacency relationship of the map files CF forming the first database 111 by directory names and file names based on a tree structure. The file system on the side of the center station 2 includes a reception request analysis unit 22 and a read control unit 23. The file system on the side of the center station 2 stores the second database in the second storage device 24.
The storage area of the storage 25 is divided into "directories" (logical areas), and the parent-child relationship and the adjacent relationship of the map files CF forming the second database 25 are represented by directory names and file names based on a tree structure.

FIG. 5 is a diagram showing a tree structure for managing the map file CF shown in FIGS.
As described above, each directory of each file system has a tree structure as shown in FIG. 5 and is represented by a “@” mark. The “@” mark is an identifier for identifying a directory. The top directory is called a root, and is represented by “$ MAP”. The directory under the root directory “$ MAP” can store the map file CF itself or a subdirectory. Here, when the file system specifies a necessary map file CF, the directory name existing from the root “$ MAP” to the directory where the map file CF exists is indicated by “path” before the file name.
Must be written as Therefore, two "￥"
The character string between the marks represents the directory name. The first letter of the subdirectory name is defined as “D”. The first letter of the file name is defined as "M".
Further, the extension of the file name is defined as “.map”.

Next, a method of assigning a directory name and a file name, which is one feature of the present embodiment, will be described. First, in principle, a map file CF representing a map covered by each unit of the highest hierarchy is given a file name according to a predetermined rule, and has a route (“@ma
p ”) is stored in a directory (logical area) immediately below. For example, the unit U ₃ shown in FIG. 3 belongs to the highest level (level “3”), and is 16th in the east longitude direction and north latitude direction based on the origin (latitude 0 °, longitude 0 °). Corresponds to the sixth unit (however, units including the origin are counted as the 0th unit). For this reason, the unit U _3, is named "M1606.map" including the first letter and the extension of the file name.
Further, the unit U ₃ in the top hierarchy is located at the root (“@m
ap ”), the path is“ $ MAP ”.
¥ M1606. map ". As it can be seen from the above file name of the unit U _3, between the first letter and the file name extension, lined four digits. The upper two digits define the position of the unit U as counted from the origin in the east longitude direction. The lower two digits specify the position of the unit U as counted in the north latitude direction from the origin. Thus, the file name defines the position of the unit U. In addition, as can be seen from the path of the unit U _3, root ( "¥ map") is not interposed subdirectory is up to the file name from. As described above, the number of subdirectories defines which hierarchy the unit U belongs to. In the case of the unit U ₃ , since the number of subdirectories interposed between the root and the file name is “0”, the unit U ₃ (M160
6. It can be seen that map) belongs to the highest hierarchy. According to the above rules, the path for the unit U of the other highest hierarchy is “$ MAP \ M0000.map”, “$ MA
P @ M0001. map ", ..." ¥ MAP ¥ M160
6. map "...

A subdirectory for storing a group of units having the unit U of the highest hierarchy as the parent unit PU is created immediately below the root. For example, to store the group of units U of the unit U ₃ and the parent unit PU, "¥ D1606" named subdirectory is created under the root. As can be seen from the above subdirectory name, the first letter of the subdirectory name is followed by a four-digit number. The four-digit number indicates the position of the parent unit PU as counted from the origin in the east longitude and the north latitude, as in the case of the file name. Therefore, the route ("$ MAP")
, "$ D0000", "$ D000 1" ,
.., “￥ D 1606”,.

Next, each unit U belonging to the level "2" is given a file name based on the position code.
It is stored in a directory (logical area) immediately below a subdirectory representing its own parent unit PU. For example, there are 64 units U of level “2” with the unit U ₃ as the parent unit PU, as shown in FIG. Unit U ₂ which is one of them, since the position code "0401", including acronyms and extension of the file name "M
0401. map ". further,
The unit U _{2 at} level “2” is a subdirectory of the unit U ₃ (parent unit PU) (“\ map \ D160
6 ”), the path is stored in“ {MAP} ”.
D1606 @ M0401. map ". As can be seen from the above unit U ₂ filename, level "2"
The above-described position codes are arranged between the initial letter and the extension of the file name of the unit U. Therefore, the file name of the unit U of level “2” also defines the position of the unit U. As can be seen from the path of the unit U _2, intervening only one subdirectory from the root ( "¥ map") to the file name. The number of subdirectories defines which layer the unit U belongs to. When the unit U _2, by the number of sub-directories existing between the root and the file name is "1", the unit U
₂ (M040.map) belongs to the level “2” hierarchy. According to the above rules, the other level “2” path is “¥ MAP ¥ D0000 ¥ M000”.
0. map "," \ MAP \ D0000 \ M0001.
map ", ...," {MAP ¥ D0000 ¥ M0007.
map "," \ MAP \ D0000 \ M0100.ma
p ", ..." ¥ MAP ¥ D0000 ¥ M0707.ma
p "," \ MAP \ D0001 \ M0000.ma
p ", ..." \ MAP \ D1606 \ M0001.ma
p ", ...," \ MAP \ D1606 \ M0401.ma
p ", ..." \ MAP \ D1606 \ M0707.ma
.., etc.

Similarly, a group of units having the unit U ₂ of level “2” as the parent unit PU is stored under a directory (logical area) under the subdirectory “$ D0401”. For example, unit U
₁ is one of child unit CU of the unit U _2,
Among the unit U ₂ is 64 divided units U, is a unit corresponding to the position code "0503". Therefore, the path for the unit U ₁ is, "¥ MAP ¥ D1
606 {D0401} M0503. map ". Similarly, the path of each unit at level “1” with unit U ₂ as the parent unit PU is “{MAP} D160
6 ￥ D0401 ￥ M0000. map ”,“ {MAP}
D1606 {D0401} M0001. map ", ...,
"￥ MAP ￥ D1606 ￥ D0401 ￥ M0707.m
ap ”.

Further, the group of the unit U having the unit U ₁ as the parent unit PU is “{MAP} D 1606.
It is stored in a directory (logical area) immediately below the subdirectory represented by “¥ D0401 ￥ D0503”. The unit U ₀ belonging to such a group has a position code “020” of the unit U obtained by dividing the unit U ₁ into 64.
1 ". Therefore, unit U
The path of “ ₀ ” is “¥ MAP ¥ D1606 ¥ D0401 ¥ D
0503 @ M0201. map ". Similarly,
The path of each unit of level "0" to the unit U ₁ and the parent unit PU, "¥ MAP ¥ D1606 ¥ D040
1 @ D0503 @ M0000. map ”,“ {MAP}
D1606 @ D0401 @ D0503 @ M0001. m
ap ", ..." \ MAP \ D1606 \ D0401 \ D0
503 @ M0707. map ".

The hierarchical structure and file names realized by the map file CF have been described above. here,
The above-mentioned unit U is converted into digital data and necessary management information is added thereto, so that one map file CF
(See FIG. 7 for details). In the following description, the unit data means the unit U converted into digital data. That is, one map file CF
Contains one unit data. Next, the data structure of the map file CF will be described in detail.

[Data Structure of Map File CF] FIG. 6
FIG. 4 is a diagram for explaining a map drawn based on one map file CF. FIG. 7 shows the data structure of one map file CF. In FIG. 7, the map file CF generally includes a unit header and unit data. First, the unit data will be described. Generally, a map is composed of a background, roads, map symbols, and characters as shown in FIG. However, the map file CF is mainly used for display on the display of the terminal device 1, map matching, or route search processing. For example, in the route search process, it is only necessary to know the connection of roads, and the need for a background is low. Therefore, as shown in FIG. 6, one unit data is divided into character / symbol data, road network data, and background data and converted into data. Thus, the character / symbol data, the road network data, and the background data can be used independently. The character / symbol data means data consisting of a character string (such as a place name and an intersection name) to be described on a map covered by the unit U, and data consisting of a map sign to be described on the map. The road network data refers to roads to be displayed on the map covered by the unit U and graphic data representing connections between roads. The background data means graphic data representing a background to be represented on a map covered by the unit U, such as a water system, a mountain system, and a building. Examples of backgrounds are rivers, lakes, mountains, green belts, railways, buildings, bridges, and parks. The above character symbol data,
By superimposing and displaying the road network data and the background data, as shown in FIG. 6, the unit data can represent the background, roads, map symbols, and characters.

Next, the detailed data structure of the background data is
This will be described with reference to FIGS. As shown in FIG. 7, the background data includes a basic background table and a detailed background table. The basic background table is shown in FIG.
As is clear from (a), figure data that is an outline when displaying the background of a map, such as rivers, railways, and green belts, is a set. On the other hand, the detailed background table is a set of graphic data for displaying the map background such as a bridge and a building in more detail, as is clear from FIG. 8B. The basic background table and the detailed background table are recorded separately from each other in the unit data, as is apparent from FIG. Further, information that mutually references is not recorded in the basic background table and the detailed background table. That is, when the background data constituting the basic background table is drawn, no background data of the detailed background table is referred to. Conversely, when background data constituting the detailed background table is drawn, no background data of the basic background table is referred to. Thus, the basic background table and the detailed background table have independent data structures. Therefore, when the background is displayed on the display, it is possible to display the background represented by only the basic background table, as shown in FIG. This allows the user of the terminal device 1 to see a schematic map. In addition, as shown in FIG. 8C, the background represented by the basic background table and the detailed background table can be displayed. In this case, the detailed background obtained from the detailed background table is superimposed on the schematic background obtained from the basic background table with reference to the predetermined origin. This allows the user of the terminal device 1 to see a detailed map.
In the present embodiment, the background data is described as being composed of the basic background table and the detailed background table. However, when the first storage device 19 or the second storage device 24 has a limited storage capacity or the like, From the viewpoint of reducing the size of the first database 111 or the second database 25, the background data may include only the basic background table. Conversely, as described in the present embodiment, when the background data is composed of the basic background table and the detailed background table, the center station 2 can provide a detailed map to the terminal device 1. The terminal device 1 can display a detailed map on the display.

The data structures inside the above-described basic background table and detailed background table are the same as each other. Hereinafter, the basic background table and the detailed background table are collectively referred to as a background table, and both data structures will be described in more detail. As described above, the background table is a set of graphic data used for drawing the background of the map on the display. Rivers, parks, factories, railways, and the like are drawn on the display by each figure data.
Hereinafter, rivers, parks, factories, railways, and the like, which are the background elements of these maps, will be collectively referred to as “drawing objects”. Here, FIG. 9 is a diagram illustrating the concept of a drawing object. As is clear from the above, a drawing object represents a group of objects that are meaningful in themselves, such as a park or a factory, and has a data structure of element points for drawing the object with a polygonal line. Consists of a row. For example, FIG. 9 shows a unit U in a rectangular area.
It is shown. The range covered by unit U is 2
There are two drawing objects DO1 and DO2.
The drawing object DO1 is composed of the objects OBJ1 and O
And 2. The object OBJ1 is an area surrounded by a polygonal line created when one stroke is drawn in the order of element point a → element point b → element point c → element point d → element point e → element point a. The object OBJ2 is an area surrounded by a polygonal line drawn when one stroke is drawn in the order of element point f → element point g → element point h → element point i → element point f. The drawing object DO2 is the object O
BJ3. The object OBJ3 is an area surrounded by a polygonal line drawn when one stroke is drawn in the order of element point j → element point k → element point l → element point m → element point n → element point j. As is clear from the above, the drawing object of the present embodiment is represented by one or more objects that can be obtained by drawing a plurality of element points with one stroke.

FIG. 10 is a diagram showing a detailed data structure of the background table, that is, the basic background table or the detailed background table. In FIG. 10, the background table stores the number M of background records and M background records BR1.
To BRM. Here, M is a natural number of 1 or more. The background record number M is information indicating the number of background records BR1 to BRM included in the background table. The background record BR1 includes a background attribute, the number of objects N, the number of element points N1 to NN of the objects OBJ1 to ON, and the object records OR1 to ORN. The background attribute is information indicating the attribute of the background represented by each object OBJ included in the background record BR1. More specifically, the background attribute is a color code and a texture mapping code of each object OBJ included in the background record BR1. Here, as one feature of the present embodiment, only one color code or texture mapping code is described in the background attribute. That is, for example, a color code indicating “blue” and a color code indicating “red” are not described together in the background attribute. Only the color code indicating “blue” or only the color code indicating “red” is described in the background attribute.

The object number N is information indicating the number of objects OBJ included in the background record BR1. The number of element points N1 is the object OBJ1.
Indicates the number of element points that make up. The element score N2 is
It shows the number of element points that make up the object OBJ2. Hereinafter, similarly, the number of element points NN is the object OB
Shows the number of element points of JN. Thus, the background record B
In R1, the number of element points constituting the N objects O included therein is arranged. Here, N is a natural number of 1 or more.

Further, the object record OR1 is
This is information indicating the coordinates of the element points forming one object OBJ1. It should be noted here that since the object OBJ1 includes a plurality of element points, a plurality of pieces of coordinate information are arranged in the object record OR1. That is, the information of the coordinate sequence is described in the object record OR1. Here, as is clear from the above, the object record OR1 describes coordinate information of a number corresponding to the number N1 of element points. The object record OR2 is information indicating a coordinate sequence of element points constituting the object OBJ2. Object record OR2
Describes coordinate information of a number corresponding to the number N2 of element points. Hereinafter, similarly, the object record ORN is
This is information indicating a coordinate sequence of NN element points constituting the object OBJN. In the object record ORN, coordinate information of a number corresponding to the number of element points NN is described.

As described above, each object record O
In R, a coordinate sequence of element points constituting the object OBJ is described. As a method of expressing a coordinate sequence, a unit U
There is a method of expressing the coordinates by absolute coordinates within the element, and a method of expressing the coordinates by using a difference between the coordinates of a certain element point and the coordinates of the immediately preceding element point. Since the absolute coordinates are the coordinates of each element point with respect to a predetermined origin in the unit U, a large number of bits are required. Therefore, it is preferable to use relative coordinates as a method of expressing a coordinate sequence from the viewpoint of reducing the data size of the map file CF. Less than,
The absolute coordinates and the relative coordinates will be described in detail.

FIG. 11 is a diagram for explaining that the absolute coordinates require a large number of bits. FIG.
The figure data composed of the element points P0 to P7 is shown. The absolute coordinates of the element point P0 are (X0, Y0) based on a predetermined origin. Hereafter, similarly,
The absolute coordinates of the element points P1 to P7 are (X1, Y1) to (X
7, Y7). FIG. 12 shows the above P0 to P7
Is a diagram when each absolute coordinate information is described in an object record OR. Now, the absolute coordinates of the element points P0 to P7 are
If each of the east longitude direction (x-axis direction) and the north latitude direction (y-axis direction) is expressed by 2 bytes, for example, P0 to P
In order to describe each absolute coordinate information of No. 7 in the object record OR, 32 bytes are required.

FIG. 13 is a diagram when the respective element points P0 to P7 of the same graphic data as in FIG. 11 are represented by relative coordinates. In FIG. 13 , the graphic data includes element points P0 → P1.
One stroke is written in the order of → P2 → P3 → P4 → P5 → P6 → P7. Even in the case of the relative coordinate expression, the first element point P0 drawn with one stroke is represented by (X0, Y0) on the basis of a predetermined origin, similarly to the absolute coordinate expression. However, the next element point P1 is represented by (X1, Y
1). However, in the relative coordinate expression, the element point P
1 is represented by (ΔX1, ΔY1). Here, ΔX1
Is ΔX1 = X1−X0. ΔY1 is ΔY
1 = Y1-Y0. Subsequent element points P2 to P7 are also represented by a difference between the absolute coordinates of each element point and the absolute coordinates of the immediately preceding element point. FIG. 14 shows the above element point P
Each relative coordinate information of 0 to P7 is used as an object record OR
FIG. 7 is a diagram showing a data structure when described in FIG. It should be noted here that the relative coordinate expression is represented by the difference between the absolute coordinates of each element point and the absolute coordinates of the immediately preceding element point, and therefore, ΔX1≪X1, ΔX2≪X2,. Becomes Similarly, ΔY1≪Y1, ΔY2≪Y2,.
≪Y7. Therefore, the relative coordinates of the element points P1 to P7 are east longitude (x-axis direction) and north latitude direction (y-axis direction).
Instead of being represented by 2 bytes, each is represented by 1 byte. As a result, the element points P1 to P7
14 bytes are required to describe each relative coordinate information in the object record OR. However, since the first element point P0 needs to be described in absolute coordinates,
In order to describe each piece of coordinate information of the element points P0 to P7 in the object record OR, 19 bytes including information on the number of differences ("7") is required.

As described above with reference to FIGS. 11 to 14, when each element point P constituting the object OBJ is expressed using relative coordinates, compared with the case where only the absolute coordinate expression is used, The size of the object record OR is reduced. However, if each element point constituting the object OBJ is unconditionally represented by relative coordinates, a problem that a reduction in data size cannot be realized may occur. Such a problem will be described with reference to FIG. FIG. 15 shows an object OBJ composed of element points P0, P1, and Pn. Now, the element point P1 is represented by (ΔX1, ΔY1) in relative coordinates. It is assumed that both ΔX1 and ΔY1 can be represented by one byte. Similarly, the element point Pn is represented by (ΔX
n, represented by delta Yn). However, it is assumed that ΔXn and / or ΔYn are values that cannot be represented by one byte because the element point Pn is at a position away from the immediately preceding element point P1. In such a case, it is necessary to create new element points P2 and P3 on a straight line connecting the element points P1 and Pn as shown in FIG. Thus, the relative coordinates of the element point Pn can be represented by (ΔX4, ΔY4) based on the absolute coordinates of the immediately preceding element point P3.
ΔX4 and ΔY4 can be represented by 1 byte because the element point P3 is located closer to the element point Pn than the element point P1. The above element points P0, P1, P2, P3 and Pn
When each piece of relative coordinate information is described in the object record OR, 13 bytes are required as shown in FIG.

As described above with reference to FIGS. 15 to 17, when two element points P are located apart from each other, it is necessary to supplement a new element point P. As a result, the relative coordinate information of the supplementary element point P must be described in the object record OR. As described above, if all the element points P except the first element point P are to be represented by relative coordinates, the number of element points P becomes unnecessarily large, and the data size of the object record OR becomes unnecessarily large. The problems come to light. Therefore, it is effective to represent the element points P0 and Pn in FIG. 15 by absolute coordinates and to represent the element point P1 by relative coordinates with respect to the element point P0. Now, assuming that the absolute coordinates of the element point Pn are (Xn, Yn) that can be expressed by 4 bytes, the element points P0,
Each coordinate information of P1 and Pn is stored in the object record O
When described in R, it becomes as shown in FIG. In FIG. 18, the absolute coordinate information of each of the element points P0 and Pn is 4 bytes, and the relative coordinate information of the element point P1 is 2 bytes. Further, the information on the number of differences indicating how many relative coordinates are created based on P0 and Pn expressed in absolute coordinates is 2 bytes. When the above total is obtained, the data size of the object record OR is 12 bytes. This data size is the data size 1 of the object record OR when expressed only by relative coordinates.
It is smaller than 3 bytes (see FIG. 17).

As described above with reference to FIG.
An element point located apart from the immediately preceding element point is represented by absolute coordinates. As described above, in the present embodiment, a certain element point is mainly represented by relative coordinates, while other element points are represented by absolute coordinates. This makes it possible to further reduce the data size of the object record OR.

As described above, in this embodiment,
The relative coordinate representation is also applied to the boundaries of the object.
Here, the boundary of an object is an object O
It means a portion that pen-ups from one element point P constituting BJ and pen-down to one element point P constituting another object OBJ. By applying the relative coordinate expression, the present embodiment has a technical effect that the data size of the background table can be reduced. Below,
First, in order to clarify the technical effect, a case where the relative coordinate expression is not applied to the boundary of the object will be described with reference to FIGS. FIG. 19 shows the drawing object DO3. The drawing object BO3 is composed of objects OBJ3 and OBJ
4 The object OBJ3 is composed of six element points P0 to P5. Object O
BJ4 is composed of four element points P6 to P9.

The above object OBJ3 has the element point P
One stroke is written in the order of 0 → P1 → P2 → P3 → P4 → P5 → P0. Thereafter, pen-up is performed at element point P0, and pen-down is performed at element point P6. Then, the object OBJ4 has the element points P6 → P7 → P8 → P9
→ One stroke is written in the order of P6. At this time, assuming that the relative coordinates are not applied at the boundary of the object, the data structure of the coordinates representing the element points P0 to P5 and the element points P6 to P9 is as shown in FIG. In FIG. 20, first, the absolute coordinates (X0, Y0) of the element point P0 serving as the reference point of the object OBJ3 are described in 4 bytes. At the time of drawing the object OBJ3, the element points P1 to P1
Since it follows P5, the number of differences (that is, the number of relative coordinates) is 5, which is 1-byte information. Now, the relative coordinates of the element points P1 to P5 are represented by 2 bytes, as described above, and are (ΔX1, ΔY1) to (ΔX5, ΔY5). In addition, since the relative coordinates are not applied to the boundary portion of the object, the absolute coordinates (X
1, Y1) is described in 4 bytes. Object OB
When J4 is drawn, the element points P7 to P9 are traced after pen-down to element point P6 after pen-up, so that the number of differences (the number of relative coordinates) is three, which is 1-byte information. . The relative coordinates of the element points P7 to P9 are
(ΔX6, ΔY6) to (ΔX8, ΔY8), represented by 2 bytes. Therefore, the relative coordinate sequence of the objects OBJ3 and OBJ4 is represented by 26 bytes without applying the relative coordinates to the boundary between the two objects.

Next, a case where the relative coordinate expression is applied to the boundary of the object will be described with reference to FIGS. 21 and 22. FIG. 21 shows a drawing object DO3 composed of two objects OBJ3 and OBJ4, as in FIG. The drawing object DO3 has element points P0 → P1 → P2 → P3 → P4 → P5
Is written in the order. Then, after pen-up and pen-down from the element point P5 to the element point P6 are performed, the drawing object DO3 is changed from the element point P6 to P7 to P
One stroke is written in the order of 8 → P9 → P6. However,
At the time of drawing, there is a principle that the start point of one-stroke writing and the pen-up point are always connected, so the element point P5 and the element point P0 are connected by a line. In the above drawing,
Assuming that relative coordinates are applied at the boundary of the object, the data structure of the coordinates representing the element points P0 to P5 and the element points P6 to P9 is as shown in FIG. In FIG. 22, first, the absolute coordinates (X0, Y0) of the element point P0 serving as the reference point of the object OBJ3 are described in 4 bytes. When drawing the drawing object DO3, the element points P1 to P1 are drawn from the element point P0 to the end of the stroke.
Since it follows P9, the number of relative coordinates, that is, the difference number is 1-byte data and indicates "9".
Now, the relative coordinates of the element points P1 to P9 are represented by 2 bytes in the same manner as described above, and (ΔX1, ΔY1) to (ΔX9, ΔY
9). Therefore, when the relative coordinates are applied to the boundary between the two objects, the relative coordinate sequence of the objects OBJ3 and OBJ4 is represented by 23 bytes.

As described above with reference to FIGS. 19 to 22, when the relative coordinates are applied to the boundary of the object,
The data size of the background table can be reduced as compared with the case where it is not applied.

It should be noted here that in FIG. 20, the boundaries of the objects can be known from the absolute coordinates described in the object record OR. However, in FIG. 22, the boundary of the object cannot be found from the absolute coordinates. As shown in FIG. 21, the element point P for pen-up and the element point P for pen-down that define the boundary of the object may be indicated by relative coordinates, and further, as shown in FIG. This is because if the distance is long, the element point P may be represented by absolute coordinates. However, in FIG. 22, the boundaries of the objects can be accurately defined by referring to the element point numbers N1 to NN shown in FIG. In other words, in the present embodiment, the number of element points N1 to the number of element points NN each mean the number of element points to be traced in one stroke from pen down to pen up. Therefore, at the time of actual drawing, the number of coordinates is counted from the head of the object record OR, and the counted value is the number of element points N
If the same as 1, the boundary of the first object can be specified accurately. Similarly, if the count value is the same as the sum of the element points N1 and N2, the boundary of the second object can be specified. Thereafter, similarly, if the count value is the same as the added value of the number of element points N1 to NN, the boundary of the Nth object can be specified.

[Detailed Data Structure of Character / Symbol Data] Next, the character / symbol data shown in FIG. 7 will be described. Since the character / symbol data is not a characteristic feature of the present invention, it will be briefly described. As described above, the character / symbol data includes data consisting of character strings (place names, road names, intersection names, etc.) to be described on the map covered by the unit U, and map symbols to be described on the map. Means data. Further, the character / symbol data is shown in FIG.
As shown in FIG. 7, the table is composed of a basic character symbol table and a detailed character symbol table. The basic character / symbol table is a set of data representing the basic character strings and map symbols among the character strings or map symbols described on the map covered by the unit U. More specifically, in the basic character / symbol table, as is clear from FIG.
A character string and a map symbol, such as a road name and a map symbol, which are outlined when displaying a map covered by the unit U are recorded. On the other hand, the detailed character / symbol table is a set of data representing character strings and map symbols, which are not recorded in the basic character / symbol table, among the character strings or map symbols described on the map covered by the unit U. More specifically, in the detailed character / symbol table, as is clear from FIG. 23B, characters for displaying the map covered by the unit U in more detail, such as the names of parks, railways, bridges, and factories, are displayed. Columns and map symbols are recorded.

Here, as the terminal device 1 of the present embodiment, a car navigation system is assumed as described above. Under such circumstances, it has been described that a river name, a road name, a map symbol, and the like important for car navigation are recorded in the basic character data table. However, the terminal device 1 for other uses can also be assumed. Therefore, what character strings and map symbols are recorded in the basic character and symbol table and what character strings and map symbols are recorded in the detailed character and symbol table depend on the use of the terminal device 1. Dependent. Therefore, the technical scope of the present invention should not be interpreted as limited such that the basic character / symbol data table records river names, road names, map symbols, and the like.

The basic character symbol table and the detailed character symbol table described above are recorded in separate fields in the unit data, as is apparent from FIG. Further, the basic character symbol table and the detailed character symbol table do not record any information that is mutually referred to. That is, when a character string or a map symbol constituting the basic character / symbol table is drawn, no character string or map symbol in the detailed character / symbol table is referred to. Conversely, when a character string and a map symbol constituting the detailed character / symbol table are drawn, no character string or map symbol in the basic character / symbol table is referred to. Thus, the basic character symbol table and the detailed character symbol table have independent data structures. Therefore,
When a character string and a map symbol are displayed on a display, a character string and a map symbol represented only by a basic character symbol table can be displayed as shown in FIG. Thereby, the user of the terminal device 1
You will be able to see a schematic map. FIG.
As shown in (c), a character string and a map symbol constituting each of the basic character symbol table and the detailed character symbol table can be displayed. In this case, a character string and a map symbol obtained from the detailed character / symbol table are superimposed on a schematic character string and a map symbol obtained from the basic character / symbol table with reference to a predetermined origin. This allows the user of the terminal device 1 to see a detailed map. In the present embodiment, the character / symbol data is described as including the basic character / symbol table and the detailed character / symbol table. However, the first storage device 19 or the second storage device 24 has a limited storage capacity. In some cases, from the viewpoint of reducing the size of the first database 111 or the second database 25,
The character / symbol data may be composed of only the basic character / symbol table. Conversely, as described in the present embodiment, when the character / symbol data is composed of the basic character / symbol table and the detailed character / symbol table, the center station 2 provides a detailed map to the terminal device 1. And the terminal device 1 can display a detailed map on the display.

The internal data structures of the basic character symbol table and the detailed character symbol table are the same. Hereinafter, the basic character symbol table and the detailed character symbol table are collectively referred to as a character symbol table, and both data structures will be described in more detail.

As described above, the character / symbol table is a set of data for representing the character strings and map symbols on the map covered by the unit U on the display. Here, FIG. 24 is a diagram showing a detailed data structure of the character symbol table, that is, the basic character symbol table or the detailed character symbol table. 24, the character / symbol table includes a character / symbol record number P and P character / symbol records TSR1 to TSRP. The number P of character symbol records is information indicating the number of character symbol records TSR1 to TSRP included in the character symbol table. Here, P is one or more natural numbers, and is the total number of character strings and map symbols on the map covered by the unit U. The character symbol records TSR1 to TSRP are created by the number of character strings or map symbols on the map covered by the unit U. The character / symbol record TSR1 has a character / symbol attribute,
It consists of point coordinates and character code.

The character / symbol attribute is a character / symbol record TSR.
1 is information indicating an attribute of a character string or a map symbol to be represented by 1. Information indicating the size of the character string or the map symbol and the direction (vertical / horizontal) in which the character string is arranged is recorded in the character symbol attribute. It should be noted here that a map symbol rarely represents one target by a plurality of symbols, and furthermore, there is a place name represented by one character.
In such a case, there is no particular need to record information indicating the direction (vertical / horizontal) in which the character strings are arranged in the character / symbol attribute. The point coordinates are coordinate information for specifying a position on the unit U at which a character string or a map symbol to be represented by the character / symbol record TSR1 is displayed. A character string or the like to be represented by the character / symbol record TSR1 is displayed on the display at a position specified by the point coordinates. The character symbol code is a code number of a character string and a map symbol to be represented by the character symbol record TSR1. As a code number of a character string, a shift JIS code is typical in Japan, and information corresponding to a size representing the size of a character string recorded in a character symbol attribute is recorded. Here, the map symbol is created independently since there is no standard related to it, such as shift JIS. Furthermore, as a code number of the created map symbol, an empty code number of Shift JIS is assigned in Japan. The assigned code number is recorded as a character code. Note that the other character / symbol records TSR2 to TSRP are
1 has the same data structure as that of FIG.

[Detailed Data Structure of Road Network Data] Next, the road network data shown in FIG. 7 will be described. The road network data is used not only for displaying the road on the display in the terminal device 1 as a car navigation system,
It is also used for map matching, route search processing or route guidance processing. Therefore, the road network data
As described above, it means a set of graphic data representing the road itself to be represented on the map covered by the unit U and data representing the connection between the roads. More specifically, since the road network data is used for map matching and the like, the road network data not only records the graphic data representing the shape of the road network, but also covers the area covered by the unit U. Also, data indicating the connection relationship between roads represented on the map is recorded.

The above road network data is composed of first network data and second network data as shown in FIG. In the first network data, road network data of a main arterial road is recorded. The main arterial road means, for example, one that satisfies any of the following three conditions. First, the first condition is that a road (highway, national road) built by a local government or a higher-ranking administrative organization. The second condition is that the road is a road (highway, national road) and a private road that are built by an administrative organization lower than the local government, and that the road has a width of 5.5 m or more. The third condition is that the road is a road connected to a road that meets the above first and second conditions. In addition, road network data of a narrow street is recorded in the second network data. A narrow street is 3.0 m or more in width,
It means a road that does not fall under the main arterial road (for example, a road built around a house). However, the above definitions of the main arterial roads and narrow streets are merely examples, and other definitions may be adopted. Therefore, the technical scope of the present invention is that the first and second road network data include:
It should not be construed that the road network data corresponding to only the above definition is recorded.

Next, the relationship between the first road network data and the second road network data will be described with reference to FIG.
This will be described with reference to FIG. The first road network data is road network data of a main highway. Therefore, when the first road network data is displayed on the display of the terminal device 1, as shown in FIG. 25 (a), a figure representing the main highway is displayed. On the other hand, the second
Is road network data of narrow streets. Therefore, when the second road network data is displayed on the display of the terminal device 1, FIG.
As shown in FIG. 5B, a figure representing a narrow street is displayed. These first and second road network data are recorded separately from each other in the unit data, as is apparent from FIG. Therefore, as shown in FIG. 25A, it is possible to display only the main highways constituting the first road network data on the display of the terminal device 1. This allows the user of the terminal device 1 to see a schematic road network. In addition, as shown in FIG.
The main arterial roads and narrow streets constituting the road network data can be displayed. In this case, based on the predetermined origin, the narrow street road network obtained from the second road network data is superimposed on the main arterial road network obtained from the first road network data. Thereby, the user of the terminal device 1 can see the detailed road network. In the present embodiment, the road network data has been described as being composed of the first and second road network data.
If the first storage device 19 or the second storage device 24 has a limited storage capacity, the first database 111
Alternatively, from the viewpoint of reducing the size of the second database 25, the road network data may include only the first road network data. Conversely, as described in the present embodiment, the road network data is
And the second road network data, the center station 2 can provide a detailed road network to the terminal device 1, and the terminal device 1 can display the detailed road network on a display. Become

The data structures of the first and second road network data are the same as each other. Hereinafter, the data structures of the first and second road network data will be described in more detail. As is well known, road network data mainly includes nodes and links. The node mainly means data for expressing an intersection or a road segment. Further, a link is data for expressing a road connecting two intersections. By using such nodes and links, the shapes of the roads (main arterial roads or narrow streets) to be displayed on the map covered by the unit U and the connection relationship between the roads are displayed on the display of the terminal device 1.
Therefore, as shown in FIG. 7, the first road network data is composed of a first node table and a first link table, and the second road network data is composed of a second node table and a second link table. Consists of a table. Hereinafter, the data structures of the first and second node tables will be described first.

FIG. 26 is a diagram for explaining the concept of nodes and links. FIG. 26 shows a road network existing in a range covered by one unit U. The road network of FIG. 26 has 11 nodes N0 to N10.
And 11 links L0 to L10. 1
One node N0 to N10 is roughly classified into a non-adjacent node and an adjacent node. Non-adjacent nodes are normal intersections,
Alternatively, it is a node created at a point where the type or attribute of the road changes (corresponding to the above-described road segment), and means a branch point indicating a connection relation of roads in the unit U.
By the way, the unit U in FIG. 26 has some adjacent units U which belong to the same level and are adjacent (see FIG. 2).
Therefore, one road may span a plurality of units U adjacent to each other. Hereinafter, a unit U adjacent to the unit U in FIG. 26 is referred to as an adjacent unit NU for convenience. In FIG. 26, one of the adjacent units NU is indicated by a dotted line. The adjacent node is a node created on the boundary of the unit U (that is, the side of the rectangular area) when there is a road extending between the unit U and the adjacent unit NU in FIG. It means a point representing the road connection relationship with the unit NU. According to the above definitions, nodes N1 and N1 in FIG.
Two of N2, N5 and N8 (see circles) are classified as non-adjacent nodes. Also, nodes N0, N3, N4, N6,
Seven of N7, N9, and N10 (see ● marks) are classified as adjacent nodes. It should be noted here that, when a node N representing an intersection or a road segment exists on the boundary of the unit U, it is important to classify the node N as an adjacent node or a non-adjacent node. Becomes In such a case, a new non-adjacent node may be created by shifting a node N representing an intersection or a road segment from the boundary.
There are two solutions. As another countermeasure, unit U
May create non-adjacent nodes on the same coordinates as intersections or road breaks on the boundary of As is clear from the above, an adjacent node must not be created on the boundary of the unit U.

FIG. 27 is a diagram showing a detailed data structure of the first node table. Here, it should be noted that the first and second node tables have the same data structure as each other, and are different in that they are created for the main arterial road and the narrow street. Therefore, the detailed description of the second node table is omitted from the viewpoint of simplifying the description. By the way, in FIG. 27, the first node table includes the number of adjacent nodes Q, the number of non-adjacent nodes R, and (Q +
R) node records NR1 to NR (Q + R). The number of adjacent nodes Q is information indicating the number of adjacent nodes included in the first node table. Here, Q is a natural number of one or more, and indicates how many adjacent nodes exist in the road network on the map represented by the unit U. The non-adjacent node number R is information indicating the number of non-adjacent nodes included in the first node table. Here, R is a natural number of one or more, and indicates how many non-adjacent nodes exist in the road network on the map represented by the unit U.

Node records NR1 to NR (Q + R)
Are created by the number of nodes N existing in the road network on the map represented by the unit U. Node record NR1
Information related to (Q + R) nodes N is recorded in NR (Q + R). Next, how to arrange the node records NR1 to NR (Q + R) in the present embodiment will be described. In the first node table, information related to the Q adjacent nodes is recorded in the first Q node records NR1 to NRQ, and the information is stored in the subsequent R node records NR (Q + 1) to NR (Q + R) . Records information relating to R non-adjacent nodes. Further, in the Q node records NR1 to NRQ, information related to adjacent nodes (see FIG. 26) existing on the left side of the rectangular area (unit U) is recorded in order from the top. Next, information related to an adjacent node (see FIG. 26) existing on the upper side of the rectangular area is recorded. Next, information related to an adjacent node (see FIG. 26) existing on the right side of the rectangular area is recorded. Finally, information related to the adjacent node (see FIG. 26) existing on the lower side of the rectangular area is recorded. The node records NR of the adjacent nodes on the upper side or the lower side are arranged such that the latitudes of the adjacent nodes are in ascending order. On the other hand, the node records NR of the adjacent nodes on the right side or the left side are arranged such that the longitudes of the adjacent nodes are in ascending order.

Further, the node record N of the non-adjacent node
R is initially arranged such that the latitudes of the non-adjacent nodes are in ascending order. At this time, if there are a plurality of non-adjacent nodes having the same latitude, the node records NR are arranged such that the longitudes of the non-adjacent nodes are in ascending order.

According to the above arrangement method for nodes N0 to N10 in FIG. 26, as shown in FIG. 28, information on the adjacent node N6 is recorded in the first node record NR1. The next node record NR2 includes an adjacent node N0
Information is recorded. Node records NR3, NR4,
NR5, NR6 and NR7 have adjacent nodes N4, N4
7, N10, N3 and N9 are recorded. Here, 〜 in FIG. 28 corresponds to の in FIG. 26, and indicates the order in which adjacent nodes are arranged. In the next node record NR8, information on the non-adjacent node N8 is recorded. Node records NR9, NR10 and NR
11 records information on non-adjacent nodes N5, N2 and N1. As described above, in the present embodiment, the information of the node N included in the unit U is not random,
The data is recorded in the node record NR in the order according to the rules described above. Here, in the following description, the node record number refers to a number that specifies the order of each node record NR2 and subsequent records, with the first node record NR1 being “0”. When the above node record numbers are applied to the node records NR1 to NR11 in FIG. 28, the node record numbers of the node records NR1 to NR11 are “0” to “10”. In addition,
The above arrangement is performed by the unit U and the adjacent unit NU.
Between the parent and child of the unit U, and the node and link can be accurately associated with each other.
Specific processes and effects of these will be described later.

Now, referring to FIG. 27 again, the internal data structure of node record NR1 will be described in detail. The node record NR1 includes a node attribute, node coordinates, and node connection information. The node attribute is information for representing the attribute of the node recorded in the node record NR1. Examples of node attributes include information indicating whether traffic at the intersection is regulated by the recorded node,
There is information indicating whether or not the intersection represented by the node has a name, and information such as whether or not a traffic signal exists at the intersection represented by the node. When information on the presence or absence of a traffic regulation or an intersection name is recorded in the node attribute, tables such as an intersection restriction table and an intersection name table, which are not described in the present embodiment, are separately created and the corresponding information is recorded. I do.

The node coordinates are represented by the node record NR
This is information for representing the coordinates in the longitude direction and the coordinates in the latitude direction of the node recorded in 1. As the longitude coordinates and the latitude coordinates of the node, absolute longitude / latitude coordinates may be recorded.
Using the lower left corner of (rectangular area) as a reference point,
In general, the longitude and latitude widths of the range covered by are represented by coordinates normalized by a value of about 2 bytes. For example, as shown in FIG. 29, the coordinates of the lower left corner Na of the unit U are expressed as (0000h, 0000h) (h represents a hexadecimal value), and the coordinate system of the unit U is changed in both the longitude direction and the latitude direction. Normalize at 8000 h. in this case,
The coordinates of the upper left corner Nb of the unit are (0000h, 8000
h). The coordinates of the lower right corner Nc of the unit are expressed as (8000h, 0000h). further,
The coordinates of the upper right corner Nd of the unit are (8000h, 8000
h). The node connection information is information indicating a connection relationship between a node N recorded in a node record NR1 and a link L recorded in a link record LR described later. Details of the node connection information will be described later. The other node records NR2 to NR (Q + R)
Is the same as that of the node record NR1, and a description thereof will be omitted. However, information on the different nodes N is recorded in the other node records NR2 to NR (Q + R).

Next, the data structure of the first link table shown in FIG. 7 will be described. Here, it should be noted that the first and second link tables have the same data structure, and are different in that they are created for main arterial roads and narrow streets. Therefore, hereinafter, detailed description of the second link table will be omitted. FIG. 30 is a diagram illustrating a detailed data structure of the first link table. In Figure 30, composed of a first link table, a road number S, and the S road record RR1～RR S. The number of roads S is information indicating the number of roads included in the road network represented by the first node table. Here, S is 1
The above natural numbers indicate how many roads exist in the road network on the map represented by the unit U. One road attribute is assigned to the road record RR1, and information on the link L and the node N having the same road attribute is recorded. The road record RR2 includes another one.
One road attribute is assigned, and information on the link L and the node N having the same road attribute is recorded. Or later,
Similarly, the road record RRS includes another road record R
One unassigned road attribute is assigned to R1 to RR (S-1), and the link L having the same road attribute is assigned.
And information about the node N are recorded. As is clear from the above, different road attributes are assigned to the road records RR1 to RRS. Here, the road attribute is information for classifying each road type. Typically, roads are classified into expressways, national roads, prefectural roads, city roads, private roads, and the like, and are further classified by the name of each road. If necessary, one-way regulation of the road may be adopted as the road attribute.

The road record RR1 includes a road attribute, the number of links T1, a head node record number, and T1 link records LR1 to LRT1. In the road attribute, information indicating a road type (expressway, national road, prefectural road, etc.), one-way road regulation, and the like are recorded. Number of links T1
Is information indicating the number of links L recorded in the road record RR1. Here, T1 is a natural number of 1 or more, and is information indicating how many links L corresponding to the information of the road attribute exist in the road network on the map represented by the unit U. The first node record number means a node record number for specifying a predetermined node record NR. This node record number is, as described above with reference to FIG.
This is a number specifying the order of each node record NR2 and subsequent records, where 1 is "0". further,
The predetermined node record NR means that a node N located at the head of the road network represented by the road record RR1 is recorded. In the link record LR1, information on one of the links L classified by the road attribute in the road network on the map represented by the unit U is recorded. For this purpose, the link record LR1 is composed of link attributes and link connection information. The link attribute is information indicating an attribute of the link L represented by the link record LR1. A typical example of the link attribute is a link type (a main line link,
Side road link) or the number of lanes. Also,
The link connection information is information of the node N connected to the link L represented by the link record LR1 or the link L connected to the link L represented by the link record LR1 via the node N. In the link record LR2, information about another link L classified by the road attribute is recorded. Similarly,
In the link record LRT1, other link records LR (T1-1) of the links L classified by the road attribute are included.
Is recorded with respect to one link L that is not recorded in the. Here, each of the link records LR2 to LRT includes a link attribute and link connection information, like the link record LR1. As is clear from the above, information on the different links L is recorded in the link records LR1 to LRT1.

Now, a specific example of the information described in the first link table will be specifically described for the case of the road network in FIG. As described above, the road network of FIG. 26 includes eleven nodes N0 to N10 and eleven links L
0 to L10. Further, in order to make the description more specific, it is assumed that the links L0 to L2 form one road (for example, a national road) by being connected in the order of L0 → L1 → L2 with the node N0 at the head. Assume. Under this assumption, the links L0 to L2 have the same road attribute (national road). It is assumed that the links L3 to L5 form one road (for example, a prefectural road) by being connected in the order of L3 → L4 → L5 with the node N4 at the head. Under this assumption, the links L3 to L5 have the same road attribute (prefectural road). Links L6 to L
It is assumed that the node 8 forms one road (for example, a private road having a width of 5.5 m or more) by being connected in the order of L6 → L7 → L8 with the node N7 at the head. Under this assumption, the links L6 to L8 have the same road attribute (private road). It is assumed that the links L9 and L10 form one road (for example, a city road) by being connected in the order of L9 → L10 with the node N5 at the head. Under this assumption, the links L9 and L10 have the same road attribute (city road).

Under the above assumptions, roads are national roads, prefectural roads,
Since there are four private roads and city roads, “4” is recorded as the number S of roads in the first link table. In addition, since there are four types of road attributes: national road, prefectural road, private road, and city road, four road records RR1 to RR4 are recorded in the first link table. First, the road record RR1 will be described. Information representing “national road” is recorded as the road attribute. Also, as the number of links T1,
Since the national road is composed of the links L0 to L2, information indicating "3" is recorded. The head of the road represented by the links L0 to L2 is represented by a node N0. The record number of the node N0 is “1” (see FIG. 28). Therefore, “1” is recorded as the number of the head node N. Next, in the link record LR11 (the record of the link L0), the description of the link attribute is omitted.

Now, the link connection information recorded in each link record LR and the node connection information shown in FIG. 27 will be described. At the same time, a process of following the connection relationship between the node N and the link L will be described. For example, as shown in FIG. 26, the node N2 has links L1, L2, and L2.
6 and L7. As described above, the four links L1, L2, and L are centered on each node N2.
6 and L7 are connected. In the node record NR10, information related to the node N2 is recorded (see FIG. 27). Also, link records LR12, LR
13, LR31 and LR32 have links L1, L
2, information related to L6 and L7 is recorded (FIG. 3)
1). Node connection information of the node record NR10 (see FIG. 27), and each link record LR12, L
The link connection information of R13, LR31 and LR32 (see FIG. 31) includes the link L1 connected to the node N2,
Information for tracing L2, L6 and L7 is recorded. First, the node record NR10 includes, as node connection information, the first link L connected to the node N2.
Information for referring to the link record LR12 in which (it is assumed that the link is temporarily L1) is recorded is recorded. More specifically, as the node connection information, an offset address from the head of the link table to the link record LR12 may be recorded, or a link record number of the link record LR12 may be recorded. Here, the link record number refers to the link record L with the first link record LR11 in the link table being “0”.
It means a number for specifying the order of the record after R12. When the above link record numbers are applied to the link record LR in FIG. 31, the link record LR1
The link record numbers of 1 to LR13 are "0" to "3". The link record numbers of the link records LR21 to LR23 are "4" to "6". The link record numbers of the link records LR31 to LR33 are "7" to "9". Further, the link record LR4
The link record numbers of 1 and LR42 are "10" and "11".

It should be noted here that the offset address and the link record number are recorded in the node connection information only when following the connection of the road network in the same unit U. Similarly, the link connection information refers to the offset address and the node record number only when following the connection of the road network in the same unit U. Details will be described with reference to FIGS. 37 and 38. However, when following a connection of a road network that crosses the boundary between a certain unit U and an adjacent unit NU, the offset address and the link record number are not referred.

In the example of FIG. 32, the node record NR10
In the node connection information, an offset address to the link record LR12 or a link record number of the link record LR12 is recorded so that the node record NR10 can refer to the link record LR12 of the link table. In the example of FIG. 32,
Link record LR 31 from the link record LR12
Because There is referenced, the link connection information for the link record LR12, as can refer to other links L6 to be connected to the link L1, the offset address or link record for the link record LR 31 to the link record LR 31 The number is recorded. The node connection information of the node record NR10 and the link record LR1
From the link connection information of No. 2, it is understood that the link L1 is connected to the link L6 starting from the node N2.

It should be noted here that the link connection information of the link record LR12 includes not only a link record number and an offset address, but also a flag indicating that the link connection information is for another link L. Record it. It should be further noted that link connection information for referring to the link L recorded in the same road record RR is not recorded in each link record LR.
This is because the links L belonging to the same road record RR can be followed by the arrangement of the link records LR without referring to the link connection information. That is, in the road record RR1, the link record LR11 and the link record LR12 are recorded side by side in a continuous address area, so that it can be determined that the link L1 and the link L2 are connected to each other. Similarly, in the road record RR3, since the link records LR31 and LR32 are recorded side by side in the continuous address area, it can be determined that the link L6 and the link L7 are connected to each other.

The link L6 recorded in the link record LR31 referenced next to the link record LR12
Is not connected to the link L that is partitioned other than the road record RR1. Therefore, the link record LR 31
The information that can refer to the node record NR10 in which the node N2 located at the center of the links L1, L2, L6, and L7 is recorded is recorded as the link connection information. Even link connection information of the link record LR 31, the offset address or node record number of the node record NR10 to the node record NR10 are used. It is important to note here that the link record LR 3
1 is the node record NR10
In addition to the node record number or the offset address, a flag indicating that the link connection information is set in the node table NR is also recorded.

As described above, in each node record NR, only the node connection information to the link L to be connected first is recorded, and in each link record LR, other node connection information to the link L recorded therein is recorded. Link L in road record RR
The link L starting from each node N is recorded by recording the link connection information to the node record NR or the link connection information to the node record NR in which the node N as the starting point is recorded.
You can follow the connection.

[Data Structure of Unit Header] The data structure of the unit header will be described in detail again with reference to FIG. In the unit header, management information of the unit data of the map file CF is recorded. The unit header includes at least a unit ID, a version code, and a data size of eight types of tables constituting unit data. The unit ID is an identification number that can uniquely specify the unit U represented by the map file CF. More specifically, unit I
D is a number that can specify the level L of the unit U and the parent-child relationship and the adjacent relationship of the unit U, and is preferably a number that can be mutually converted with the path name of the map file CF.
For example, when the unit ID is represented by a 32-bit (4 byte) code, 2 bits from the MSB are reserved bits, the unit level L is 2 bits in order, the division position X3 in the longitude direction of level “3” is 5 bits, The division position Y3 in the latitude direction of level "3" is 5 bits, the division position X2 in the longitude direction of level "2" is 3 bits, the division position Y2 in the latitude direction of level "2" is 3 bits, and the division position of level "1" is The division position X1 in the longitude direction is 3 bits, the division position Y1 in the latitude direction at level "1" is 3 bits, the division position X0 in the longitude direction at level "0" is 3 bits, and the division position in the latitude direction at level "0". Y0 is represented by 3 bits. Here, the division position X3 in the longitude direction of the level “3” indicates what number (starting point is 0 degree longitude) counting in the east longitude direction when the unit U belongs to the level “3”. Is a number. The division position Y3 in the latitude direction of level “3” is
When the unit U belongs to the level "3", this is a number indicating the position (starting point is 0 degree north latitude) counted in the north latitude direction. Division position X2 in the longitudinal direction of level "2"
Is a number indicating the position (starting point is the lower left of the unit U of level “3”) counted in the east longitude direction when the unit U belongs to the level “2”. The division position Y2 in the latitude direction of the level “2” is located at what position (the starting point is the lower left of the unit U of the level “3”) counted in the north latitude direction when the unit U belongs to the level “2”. Is a number that indicates The division position X1 in the longitudinal direction of the level “1” is located at what position (the starting point is the lower left of the unit U of the level “2”) counted in the east longitude direction when the unit U belongs to the level “1”. Is a number that indicates The division position Y1 in the latitude direction of the level “1” is located at what number (starting point is the lower left of the unit U of the level “2”) counted in the north latitude direction when the unit U belongs to the level “1”. Is a number that indicates The division position X0 in the longitude direction of the level “0” is the number of the division in the east longitude direction when the unit U belongs to the level “0” (the starting point is the level “1”).
Is located at the lower left of the unit U). The division position Y0 in the latitude direction of the level “0” is located at what number (starting point is the lower left of the unit U of the level “1”) counted in the north latitude direction when the unit U belongs to the level “0”. Is a number that indicates

For example, the path name of the unit U ₀ of level “0” shown in FIG. 4 is “$ MAP \ D1606 \ D0401”.
¥ D0503 @ M0201. map ”, L = 0, X3 = 16, Y3 = 6, X2 = 4, Y2 =
1, X1 = 5, Y1 = 3, X0 = 2, and Y0 = 1.
In this case, the unit ID of the unit U ₀ is 13592
8529 (decimal notation). As is clear from the above, the unit ID can be uniquely specified from the path name of the map file CF, and conversely, the path name can be uniquely specified from the unit ID.

The version code is stored in the map file C
An identification code for indicating the version of F (unit U). For example, a code indicating the format version of the unit is 2 bytes, and a code indicating the content version of the unit is 2 bytes. It shall be represented by a code. When the map file CF of a certain unit ID is downloaded to the terminal device 1 from the center station 2, the version code is the map file CF of the same unit ID already stored in the first storage device 19 of the terminal device 1. It is used for determining whether or not to replace with. The detailed process at this time will be described later.

The data size of each table records the data size of each table constituting the map file CF, each of which is represented by, for example, 2 bytes. By sequentially adding the data size of each table, the map file C in which each table is stored is stored.
The offset address from the head of F can be calculated.
The data size of each table includes the data size of the basic background table, the data size of the detailed background table, the data size of the basic character / symbol table, the data size of the detailed character / symbol table, the data size of the first node table, The data size of the first link table, the data size of the second node table, and the data size of the second link table are arranged. The contents of each table are as described above.

The detailed data structure of the map file CF has been described above. Next, the first database 111
The operation of the terminal device 1 when reading out the map file CF from will be described with reference to the drawings. [Reading Process] As described with reference to FIG. 1, the terminal device 1 of the present embodiment is typically a car navigation system. As is well known, processes such as map matching, route search, and route guidance are performed. In the following, of these processes, in connection with the route search process, a process of reading a map file CF, a process of following a connection of a road extending between a certain unit U and an adjacent unit NU, and a process of linking a node N between hierarchies The process of associating with L will be described in detail. In the following, the process of obtaining the shortest route between the departure point and the destination is not the point of the present invention, and thus will not be described.

FIG. 33 is a diagram showing the concept of the route search process. As shown in FIG. 33, in the processing for obtaining the shortest route, the search is expanded from both directions of the departure point SP and the destination DP. Further, in the route search processing, map files CF of a plurality of layers from a lower layer to an upper layer are used. At this time, the shortest route is searched around the departure point SP and the destination point DP using the lower-level map file CF representing a detailed road network. On the other hand, a map file CF of a higher hierarchy representing a rough road network is used except for around the departure place SP and the destination DP. In the route search process shown in FIG. 33, a so-called bidirectional hierarchical search method is used. Further, using the map file CF, the departure point S
When finding the shortest route from P to the destination DP, the well-known Dijkstra method or the like is used. The Dijkstra method is not a point of the present invention and is a well-known technique, and thus will not be described further.

Hereinafter, the processing procedure of the bidirectional hierarchical search performed in the terminal device 1 will be described in detail with reference to the flowchart of FIG. First, in the bidirectional hierarchical search, setting of a departure place SP and a destination DP of the terminal device 1 is executed (steps S101, S102). Step S10
1 and S102, the departure point SP and the destination point D
P is set by the user of the terminal device 1 operating the input device 11 according to the menu displayed on the display of the output device 110. Here, in a recent car navigation system, a departure point SP and a destination point DP
Is generally set using an address, a telephone number, a place name or a facility name. The information for specifying the set departure point SP and destination point DP is transmitted from the input device 11 to the data processing unit 13.

When step S102 is completed, the data processing unit 13 cooperates with the read / write control unit 18 to store the map file CF required for the route search process from the first storage device 19 into the main storage (shown in FIG. (Step S103). As described above, each map file CF stored in the first storage device 19 is converted into digital data in units of a unit U obtained by dividing the map into rectangular areas as shown in FIG. Further, each map file CF is managed by a file system. The file system creates a directory so that the logical area of the first storage device 19 has a tree structure. As a result, the logical area in which each map file CF is stored is uniquely specified by the path represented by the root and the file name and the subdirectory name interposed therebetween. Further, the tree structure and the file name according to the present embodiment specify the parent-child relationship and the adjacent relationship between the units U as described above. Data processing unit 13 and read / write control unit 18 constituting the file system
Is a map file C representing the vicinity of the departure place SP transmitted from the input device 11 in the first step S103.
In order to read F from the first storage device 19, the path name of the map file CF must be obtained.

Here, FIG. 35 is a flowchart showing step S1 in FIG.
13 is a flowchart illustrating a detailed processing procedure of the third embodiment. Briefly describing the processing in FIG. 35, the map file CF is read from the level (hierarchy) of the map file CF to be read by the data processing unit 13 and the coordinate information of the point serving as the representative point.
Find the path name of Then, the read / write control unit 18 reads the map file CF from the first storage device 19 based on the path name obtained by the data processing unit 13. Hereinafter, the processing procedure when reading the map file CF (“$ M0201.map”) representing the unit U ₀ of level “0” shown in FIGS. 4 and 5 will be described with reference to the flowchart of FIG.

Here, a representative point means one point included in the range covered by the map file CF to be read. In the following description, the longitude coordinate LON ₀ and the latitude coordinate LAT ₀ are coordinates indicating the position of the representative point of the unit U ₀ in the longitude direction and coordinates indicating the position in the latitude direction. In the present embodiment, the longitude coordinate LON ₀ and the latitude coordinate LAT ₀ are 132 degrees 39 minutes 20 seconds east longitude and 32 degrees north latitude.
The degree is 55 minutes and 37 seconds.

Further, several parameters are required for the processing in step S103. In the following description, the longitude width W3 indicates that each unit U belonging to level “3”
Means the length of the side along the longitude direction of the rectangular area covered by. The latitude width H3 means the length of the side along the latitude direction of the rectangular area covered by each unit U belonging to level “3”. In the case of the present embodiment, as described with reference to FIGS. 2 and 3, when the rectangular area of level “3” is approximately 640 km square, the longitude width W3 and the latitude width H3 are 28800 seconds (8 degrees) and 19200 seconds. (5 degrees 20 minutes). The longitude width W2 means the length of the side along the longitude direction of the rectangular area covered by each unit U belonging to level “2”.
The latitude width H2 means the length of the side along the latitude direction of the rectangular area covered by each unit U belonging to level “2”. When the rectangular area of level “2” is about 80 km square, the longitude width W2 and the latitude width H2 are 3600 seconds (1 degree).
And 2400 seconds (40 minutes). The longitude width W1 means the length of a side along the longitude direction of the rectangular area covered by each unit U belonging to level “1”. The latitude width H1 is
This means the length of the side along the latitude direction of the rectangular area covered by each unit U belonging to level “1”. Level "1"
In the case where the rectangular area is about every 10 km, the longitude width W1 and the latitude width H1 are 450 seconds (7 minutes 30 seconds) and 300 seconds (5 minutes). The longitude width W0 means the length of the side along the longitude direction of the rectangular area covered by each unit U belonging to level “0”. The latitude width H0 means the length of the side along the latitude direction of the rectangular area covered by each unit U belonging to the level “0”. The rectangular area of level “0” is approximately 1.
In the case of every 2 km, the longitude width W0 and the latitude width H0 are 5
6.25 seconds and 37.5 seconds.

The data processing unit 13 first specifies the longitude coordinates LON ₀ and the latitude LAT ₀ of the representative point (step S201), and reads the level L of the map file CF to be read (the map file CF of the unit U ₀ ). In this case, L = 0) is specified (step S202). Here, steps S201 and S202 are processes generally performed in the bidirectional hierarchical search, and thus will not be described in detail here.

Next, the data processing unit 13 determines in step S2
03, the longitude coordinate LON ₀ of the representative point is set to level “3”.
Quotient when divided by longitudinal width W3 DLON3, and calculates the quotient DL AT 3 when the latitude LAT ₀ of the representative points is divided by the latitudinal width H 3 of level "3". Now, longitude width W3
= 28800 seconds (8 degrees), latitude width H3 = 19200 seconds (5 degrees 20 minutes), longitude coordinates LON ₀ = 132 degrees 39 east longitude
Since the minute is 20 seconds and the latitude coordinate LAT _{0 is} 32 degrees 55 minutes 37 seconds north latitude, the quotient DLON3 = 16 and the quotient DLAT3 = 6. The data processing unit 13 arranges the calculated quotient DLON3 and quotient DLAT3 in order to create a four-digit number. The four-digit number created this time is “1606”. Here, the quotient DLON3 and / or the quotient DLAT3
Is one digit, "0" is added to the second digit from the bottom.

The data processing unit 13 adds a directory identifier “$” and “M” defining the first letter of the file name to the beginning of the created four-digit number, and further adds the extension of the file name to the end. ".Map" is added. As a result, the data processing unit 13 determines the longitude coordinate LON of the representative point.
₀ and latitude LAT _0, (the present case, "¥ M1606.Map") of the map file CF (those units U ₀₎ to be read file names derive. Further, the data processing unit 13 adds a directory identifier “$” and “D” defining the initial of the subdirectory name to the beginning of the created four-digit number. As a result, the data processing unit 13 determines from the longitude coordinates LON ₀ and the latitude coordinates LAT ₀ of the representative point the name of the subdirectory storing the map file CF to be read (in this case, “￥
D1606 ") is derived (step S203).

Next, the data processing unit 13 determines in step S2
It is determined whether or not the level L designated at 02 is "3" (step S204). If the level L is “3”, the data processing unit 13 proceeds to step S205, adds the file name (“$ M1606.map”) derived in step S203 after the route (“$ MAP”), and
Derive the path name. Therefore, the path name is "{MAP}
M1606. map ". The data processing unit 13 outputs the derived path name to the read / write control unit 18 (Step S205). Read / write control unit 1
8 is the input path name (“\ MAP \ M1606.m
ap ”), the map file CF is read from the first database 111 in the first storage device 19. The read / write control unit 18 transfers the read map file CF to a main storage (not shown) in the data processing unit 13. Thus, the data processing unit 13 reads the map file CF from the first storage device 19 into the main storage (Step S206).

Incidentally, as described above, step S2
Since the level specified in 02 is “0”, the data processing unit 13 determines that the level L is not “3” in step S204, and proceeds to step S207. The data processing unit 13 calculates the quotient DL derived in step S203.
After calculating the remainder RLON3 of ON3, the remainder RLO
The quotient DL when N3 is divided by the longitude width W2 of level "2"
Calculate ON2. Further, the data processing unit 13 calculates the remainder RLAT3 of the quotient DLAT3 derived in step S203.
Is calculated, the quotient DLAT2 when the remainder RLAT3 is divided by the latitude width H2 of the level "2" is calculated. now,
When the above numerical values are used, the quotient DLON2 and the quotient DL
AT2 is DLON2 = 4 and DLAT2 = 1. The data processing unit 13 arranges the calculated quotient DLON2 and quotient DLAT2 in order to create a four-digit number.
The four-digit number created this time is “0401”. Here, when the quotient DLON2 and / or the quotient DLAT2 has one digit, “0” is added to the second digit.

The data processing unit 13 adds a directory identifier “$” and “M” defining the first letter of the file name to the beginning of the created four-digit number, and further adds the extension of the file name to the end. ".Map" is added. As a result, the data processing unit 13 determines the longitude coordinate LON of the representative point.
₀ and the latitude coordinates LAT ₀ , the file name of the map file CF to be read (in this case, “@ M0401.
map "). Further, the data processing unit 13
At the beginning of the created four-digit number, a directory identifier “$” and “D” defining the initial of the subdirectory name are added. Thereby, the data processing unit 13
Are the longitude coordinates LON ₀ and the latitude coordinates LAT ₀ of the representative point.
From, (those of the unit U ₀₎ map file CF to be read to derive the sub-directory name that is stored (in the case of this "¥ D0401]) (step S207).

Next, the data processing unit 13 determines in step S2
It is determined whether or not the level L designated at 02 is “2” (step S208). If the level L is "2", the data processing unit 13 proceeds to step S20 9, after the root ( "¥ MAP"), subdirectory names derived in step S203 ( "¥ D1606") and derived in step S207 File name (“@ M0401.m
ap ”) to derive the path name. Therefore,
The path name is "\ MAP \ D1606 \ M0401.ma
p ”. The data processing unit 13 outputs the derived path name to the read / write control unit 18 (step S2).
09). The read / write control unit 18 determines the input path name (“$ MAP \ D1606 \ M0401.ma
p)), the map file CF is stored in the first storage device 1
9 is read from the first database 111. The read / write control unit 18 reads the read map file C
F is transferred to a main storage (not shown) in the data processing unit 13. Thus, the data processing unit 13 reads the map file CF from the first storage device 19 into the main storage (Step S206).

As described above, since the level specified in step S202 is “0”, the data processing unit 13
The level L is determined not to be "2" in step S208, the process proceeds to step S 21 0. Data processing unit 1
3 calculates the remainder RLON2 of the quotient DLON2 derived in step S207, and then calculates the quotient DLON1 when the remainder RLON2 is divided by the longitude width W1 of the level “1”. Further, the data processing unit 13 determines in step S207
After calculating the remainder RLAT2 of the quotient DLAT2 derived in the above, the quotient DLAT1 when the remainder RLAT2 is divided by the latitude width H1 of the level “1” is calculated. Now, when the above numerical values are used, the quotient DLON1 and the quotient DLAT1 are
DLON1 = 5 and DLAT1 = 3. The data processing unit 13 calculates the calculated quotient DLON1 and quotient DLAT
1 is arranged in order to create a four-digit number. The four-digit number created this time is “0503”. Here, quotient DL
If ON1 and / or the quotient DLAT1 has one digit, “0” is added to the second digit.

The data processing unit 13 adds the directory identifier “$” and “M” defining the first letter of the file name to the beginning of the created four-digit number, and further adds the extension of the file name to the end. ".Map" is added. As a result, the data processing unit 13 determines the longitude coordinate LON of the representative point.
The file name (“$ M0503.map”) of the map file CF to be read is derived from ₀ and the latitude coordinates LAT ₀ . Further, the data processing unit 13 adds a directory identifier “$” and “D” defining the initial of the subdirectory name to the beginning of the created four-digit number. As a result, the data processing unit 13 determines from the longitude coordinate LON ₀ and the latitude coordinate LAT ₀ of the representative point the subdirectory name (in this case, “$ D0503”) in which the map file CF (for unit U ₀ ) to be read is stored. )
Is derived (step S2010).

Next, the data processing unit 13 determines in step S2
It is determined whether or not the level L specified in 02 is “1” (step S2011). If the level L is “1”, the data processing unit 13 proceeds to step S2012, after the root (“$ MAP”), the subdirectory name (“$ D1606”) derived in step S203, and step S2012.
The subdirectory name derived in step 207 (“@D 0 40
1 ") and the step S 21 0 file name derived in (¥ M0503.map) by adding, to derive the path name. Therefore, the path name is "\ MAP \ D1606 \ D
0401 @ M0503. map ". The data processing unit 13 reads the derived path name from the read / write control unit 1
8 (step S2012). The read / write control unit 18 checks the input path name (“$ MAP $ D
1606 {D0401} M0503. The map file CF is read from the first database 111 in the first storage device 19 in accordance with “map”). The read / write control unit 18 transfers the read map file CF to a main storage (not shown) in the data processing unit 13. In this way, the data processing unit 13 stores the map file CF in the first
Is read from the storage device 19 into the main memory (step S20).
6).

As described above, since the level L specified in step S202 is “0”, the data processing unit 13
The level L is determined not to be "1" in step S2011, the process proceeds to step S201 3. The data processing unit 13, after calculating the remainder RLON1 quotient DLON1 derived in step S 21 0, to calculate the quotient DLON0 when dividing the remainder RLON1 longitude width W0 of level "0". Further, the data processing unit 13 determines in step S 2
After calculating the remainder RLAT1 quotient DLAT1 derived in 1 0 latitude width H0 of the remainder RLAT1 level "0"
Calculates the quotient DLAT0 when divided by. Now, when the above numerical values are used, the quotient DLON0 and the quotient DLAT0
Is DLON0 = 2 and DLAT0 = 1. The data processing unit 13 calculates the calculated quotient DLON0 and quotient DL
AT0 is arranged in order to create a four-digit number. The four-digit number created this time is “0201”. Here, when the quotient DLON0 and / or the quotient DLAT0 has one digit, “0” is added to the second digit. The data processing unit 13
The directory identifier “$” and “M” defining the initial of the file name are added to the beginning of the created four-digit number, and the file name extension “.ma” is added to the end.
p "is added. Thereby, the data processing unit 13
The file name of the map file CF to be read (in this case, “$ M0201.map”) is derived from the longitude coordinates LON ₀ and the latitude coordinates LAT _{0 of the} representative point (step S2013). Here, in step S2013,
Since the level L can be automatically determined to be “0” of the lowest layer, the data processing unit 13 does not derive a subdirectory name.

Next, the data processing unit 13 determines in step S2
Proceeds to 014, the root ( "¥ MAP") after steps S203, S207 and arrangement of subdirectory names derived in S 21 0 ( "¥ D1606 ¥ D 0 401 ¥ D
0503) and the file name derived in step S2013 (in this case, “$ M0201.map”) is added to derive the path name. Therefore, the path name is
MAP ￥ D1606 ￥ D0401 ￥ D0503 ￥ M02
01. map ". The data processing unit 13 outputs the derived path name to the read / write control unit 18 (Step S2014). Read / write controller 18
Is the input path name (“\ MAP \ D1606 \ D0
401 @ M0503. map) according to the first database 1 in the first storage device 19.
Read from 11. The read / write control unit 18
The read map file CF is transferred to a main storage (not shown) in the data processing unit 13. In this way, the data processing unit 13 transmits the desired map file CF (unit U ₀
Data capable of displaying a map representing the
Is read into the main memory (step S206).

The data processing unit 13 performs the processing in step S2
After 06, the processing exits from the flowchart in FIG.
Go to step S104. The data processing unit 13 performs a route search process from the departure point SP using the map file CF read into the main memory (step S10).
4). It should be noted here that the technique such as the Dijkstra method is well-known, and therefore a detailed description thereof will be omitted. Briefly describing the Dijkstra method and the like, a process of obtaining the shortest route while following the connection of the road network in the map file CF is performed. The procedure for following the connection relationship between the node N and the link L in the map file CF is as described above with reference to FIG.

Further, the data processing unit 13 determines in step S1
02, in parallel with step S103, step S1
Execute 05. The data processing unit 13 performs step S10
The map file CF around the destination DP set in Step 2 is read from the first storage device 19 into a main storage (not shown) included therein (step S105). Further, the data processing unit 13 performs a route search process on the destination DP side using the map file CF read in step S105 (step S106). Here, step S105
Steps S106 and S106 are the same as steps S103 and S104, and a detailed description thereof will be omitted.

When the processing of steps S104 and S106 is completed, the data processing section 13 proceeds to step S10.
Then, it is determined whether or not the search end condition in the hierarchy of the map file CF used in S4 and S106 is satisfied (step S107). In step S107, it is generally determined whether or not the search condition has been completed based on whether or not the number of read map files CF or the number of searched nodes N has reached a predetermined value. . Step S10
If it is determined in Step 7 that the search end condition is not satisfied, the data processing unit 13 returns to Steps S103 and S105, and has already been read in the search processing from both the departure point SP and the destination DP. The map file CF adjacent to the present map file CF is read. Here, assuming that the already read map file CF represents the map of the unit U, the adjacent map file CF
Represents a map of the adjacent unit NU (see FIG. 26). The data processing unit 13 obtains the longitude coordinates LON and the latitude coordinates LAT of the new representative point, derives the path name of the adjacent map file CF, and stores the map file CF specified by the path name in the first storage device. Read from 19 into the main memory.

Here, as shown in FIG. 36, the position of the new representative point for determining the adjacent unit NU is determined by the link L that follows the connection of the road network, the adjacent node on which unit boundary (see FIG. ) Via the link L in the adjacent unit NU.
More specifically, the link L11 in FIG. 36 connects to the link L with the adjacent unit NU1 via the adjacent node N12 located on the upper side of the boundary (rectangle) of the unit U. Therefore, a point having the latitude coordinate LAT1 obtained by adding the latitude width H of the level L to which the unit U belongs to the latitude coordinate LAT of the representative point P of the unit U is determined as a new representative point P1.

On the other hand, the link L12 in FIG. 36 is connected to the adjacent node N13 located on the right side of the boundary (rectangle) of the unit U.
Through a link L in the adjacent unit NU2. Therefore, the longitude coordinates LO of the representative point P of the unit U are
A point having longitude coordinates LON2 obtained by adding the longitude width W of the level L to which the unit U belongs to N is determined as a new representative point P2.

The second and subsequent steps S103 and S1
In 05, the data processing unit 13 reads the map file CF of the map representing the range including the representative point based on the new representative point obtained as described with reference to FIG. The processing procedure at this time is as described above.
In the next steps S104 and S106, the data processing unit 13 performs a search process using the map file CF read in steps S103 and S105. This search processing is performed from the previously read map file CF to the currently read map file CF, that is, the unit U and the adjacent unit N
This means following the connection of the road network across the boundary with U.

By the way, according to the conventional technique, even if the boundary between the unit U and the adjacent unit NU is crossed, the record of the adjacent node in each map file is added to the record of the adjacent node in each map file so that the connection of the road network can be traced. Unit NU
, A number or an offset address for specifying the adjacent node is recorded. However, if such information relating to the internal data structure of the map file is recorded in the unit, when the map file representing the adjacent unit NU is updated, the number or the offset address may be changed. Therefore, there is a problem that updating one map file may require updating map files representing all neighboring units NU around the map file. In order to solve such a problem, each map file CF of the present embodiment includes:
Information directly related to the internal data structure of the adjacent unit NU is not recorded, and the data processing unit 13 traces the adjacent node N of the adjacent unit NU using the coordinate information of the node N and / or the attribute information of the link L. Execute the process.

Referring to the two drawings of FIGS. 37 and 38, in step S104 or S106 in FIG. 34, the data processing unit 13 follows the connection of the road network across the boundary between the unit U and the adjacent unit NU. The processing will be described in detail. FIG. 37 shows a road network configured when four adjacent units U1 to U4 are arranged. The road network included in the unit U1 includes four nodes N10 to N13 and three links L10 to L12. In the unit U1, three nodes N1
0, N12, and N13 (see ● marks) are adjacent nodes and are located on the boundary of the unit U1. The road network included in the unit U2 has five nodes N20 to N2.
4 and four links L20 to L23.
In the unit U2, four nodes N20 and N22 to
24 (see ●) is an adjacent node, unit U
2 is located on the boundary. The road network included in the unit U3 includes four nodes N30 to N33 and three links L30 to L32. In the unit U3, the nodes N30, N32, and N33 (see the mark ●) are adjacent nodes and are located on the boundary of the unit U3.
Further, the road network included in the unit U4 includes four nodes N40 to N43 and three links L40 to L42. The three nodes N40 to N43 (see marks ●) are adjacent nodes and are located on the boundary of the unit U4. Further, in FIG. 37, nodes N13 and N20 are connected, nodes N12 and N30 are connected, nodes N24 and N43 are connected, and nodes N33 and N40 are connected.
One road network is constructed.

In the road network shown in FIG.
12 is connected to a link L20 via adjacent nodes N13 and N20. As described above, in the route search processing, the data processing unit 13
U is read sequentially, and the destination D
The search is expanded in the direction of P or the starting point SP. To this end, the data processing unit 13 has two links L that straddle the boundary between a certain unit U and an adjacent unit NU.
It is necessary to follow the connection relationship. Therefore, first, the data processing unit 13 reads the map file CF (more specifically, the link record RR (see FIGS. 30 and 31)) of the unit U (that is, the unit U1) read into the main memory. The link attribute of the link L12 from the unit U1 to the unit U2 is extracted (FIG. 38; step S301). Hereinafter, the link L12 directed to the boundary of the unit U1 is referred to as an escape link L12.

Next, the data processing unit 13 sets the exit link L
12 with reference to the connection destination information (node record number or offset address), from the map file CF (more specifically, the first or second node table), the adjacent node N13 connected to the escape link L12 Of the node record NR (see FIG. 27). Thereafter, the data processing unit 13 extracts the node coordinates of the adjacent node N13 from the found node record NR (step S302). Hereinafter, the adjacent node N13 connected to the exit link L12 will be referred to as an exit node N13.

Next, the data processing unit 13 reads the adjacent unit NU (that is, the unit U
From the map file CF of 2) (more specifically, the first or second node table), node coordinates are extracted one by one (step S303). The data processing unit 13 calculates a difference value between the node coordinates of the escape node N13 extracted in step S302 and the node coordinates extracted in step S303, and determines whether the difference value is equal to or smaller than a predetermined threshold. (Step S304). Here, FIG.
As described with reference to No. 9, in the present embodiment, the node coordinates are recorded as normalized values. The predetermined threshold value varies depending on the width of the normalized coordinate values,
A value of about "1" to "2" is preferable. Data processing unit 13
Step S304 until the condition of step S304 is satisfied.
Steps 303 and S304 are repeatedly executed. However, every time the data processing unit 13 executes step S303, it extracts node coordinates different from those extracted in the past. Here, satisfying the condition of step S304 means that the node N having the node coordinates extracted in step S303 indicates the same position as the escape node N13. That is, the control unit 13 determines in step S30
3 and S304 are repeatedly executed, so that the adjacent node N20 having substantially the same position as the escape node N13
Can be found. Hereinafter, the located adjacent node N20 is referred to as an ingress node.

Here, generally, in step S303, the node coordinates are extracted one by one according to the order of the node record numbers (see FIG. 28). In the present embodiment, as described with reference to FIGS. 26 and 28, the node record NR of the adjacent node N is recorded before the node record NR of the non-adjacent record N in the first or second node table . Have been. As a result, the data processing unit 13 can find the entering node without extracting the node coordinates from the node record NR of the non-adjacent node N. As a result, the load of the process in which the data processing unit 13 searches for an ingress node can be minimized. That is, the data processing unit 13
The first unit recorded in the map file CF of the adjacent unit NU
Even if it is not necessary to search all the node records NR arranged in the second node table, if the node records NR are searched by the number of adjacent nodes from the head of the first or second node table, the ingress node is always determined. You can find out. As described above, the arrangement of the node records NR in the present embodiment also contributes to speeding up the process of searching for an ingress node.

Further, the node record NR of the adjacent node
Are arranged according to the priority order of the left side → the upper side → the right side → the lower side of the unit U (rectangle) as described with reference to FIG. Further, the node records NR of the adjacent nodes located on the left side and the right side are arranged in ascending order of latitude,
Node records NR of adjacent nodes located on the upper side and the lower side are arranged in ascending longitude order. The records NR of the non-adjacent nodes are first arranged in ascending latitude order, and the records N
R are arranged in ascending order of longitude. With this arrangement, the speed of the search process for the ingress node can be further increased. For example, according to the above rules of arrangement, FIG.
Nine node records NR of the nine adjacent nodes N10 to N20
Is N10 → N11 → N12 → N13 → N14 → N15
These are recorded in the map file CF of the unit U1 in the order of → N16 → N17 → N18 → N19 → N20. Similarly, the node records NR of the node table U2 of the adjacent nodes N20 to N27 are N20 → N21 → N22 → N2
It is recorded in the map file CF of the unit U2 in the order of 3 → N24 → N25 → N26 → N27. Further, in the map file CF of the unit U3, the nodes N30 → N
31 → N32 → N33 → N34 → N35 → N36 → N3
Node records NR are recorded in the order of 7 → N38.

Usually, in the route search processing, the search is expanded in the read map file CF, and when the route being searched reaches an adjacent node, the corresponding adjacent unit NU is newly read. In the present embodiment, when the map file CF of the adjacent unit NU is read, first, all the adjacent nodes existing on the boundary between the units between the previously read map file CF and the currently read map file CF Is performed. At this time, as described above, in the node table, the node records NR of the adjacent nodes are recorded in the order described above, so that the correspondence of the adjacent nodes can be sped up.
Therefore, for example, if an adjacent node N35 of the unit U3 indicating the same position as the adjacent node N12 of the unit U1 is found, the adjacent node N36 of the unit 3 corresponding to the next adjacent node N13 of the unit 1 must be a record next to the N35. Lined up. Similarly, if an adjacent node N16 of the unit 1 corresponding to the adjacent node N20 of the unit 2 is found, the adjacent node N17 of the unit 1 corresponding to the next adjacent node N21 of the unit 2 is always arranged in the record next to the N16. I have. In this way, by arranging adjacent nodes according to the above-described regularity, it is possible to speed up the process of searching for adjacent nodes between adjacent units.

When an ingress node is found in step S304, the data processing unit 13 refers to the connection destination information (node record number or offset address) of the ingress node N20 and refers to the map file CF (more specifically, the unit U2). , A link record LR (see FIGS. 30 and 31) of the link L20 connected to the ingress node N20 is found from the first or second link table. Hereinafter, the link L20 connected to the entry node N20 is referred to as an entry link L20. afterwards,
The data processing unit 13 extracts the attribute information of the incoming link L20 from the found link record LR (Step S305).

Next, the data processing unit 13 determines in step S3
It is determined whether or not the attribute information of the exit link L12 retrieved at 01 and the attribute information of the entrance link L20 retrieved from step S305 are the same (step S306). When determining that the two pieces of attribute information are different from each other, the data processing unit 13 returns to step S303 and searches for a new ingress node N. Here, in the present embodiment, as described with reference to FIG. 2, several map files CF representing maps of different scales are stored in the first storage device 19. Since the map file CF of the lower hierarchy can represent a detailed road network, if the difference value between the coordinates of the two nodes is equal to or smaller than a predetermined threshold, the probability that both nodes N indicate the same position becomes relatively high. . However, since the map file CF in the upper layer can only represent a coarse road network, even if the difference value between the two node coordinates is equal to or smaller than a predetermined threshold value, the probability that both nodes N indicate the same position is relatively low. Become. In the present embodiment, by judging whether the attributes of the exit link and the entrance link match / mismatch in step S306, the data processing unit 13 accurately identifies the same one road without following another road from a certain road. I try to follow. That is, the process of step S306 may not be performed on the lower-level map file CF.

When the data processing unit 13 determines in step S306 that the attribute information of the exit link L12 and the attribute information of the entrance link L20 match, it considers that one road is accurately traced, and proceeds from the flowchart of FIG. Then, the process proceeds to step S107 in FIG. Data processing unit 1
3 determines that the search end condition in the hierarchy of the map file CF that has been continuously read this time is satisfied,
It is determined whether or not the route on the destination side and the route on the destination DP side are connected (step S108). The data processing unit 13
If the route of the departure point SP and the route of the destination DP are connected, it is determined that the shortest route between the two points has been obtained,
The route search processing ends. On the other hand, when the route between the departure point SP and the destination DP is not yet connected, the data processing unit 13 proceeds to step S109, shifts to the next higher hierarchy, and creates a wide area and rough road network. The route search process is continued using the represented map file CF.

Next, the subsequent processing from a certain lower hierarchy to a higher hierarchy will be described in detail. At this time, the data processing unit 1
3 is the node N which is the end point of the search processing in the lower hierarchy
From (the end point of the route being searched), the processing shifts to the node N which exists in the map file CF of the upper hierarchy and indicates the same position. Therefore, in order for the data processing unit 13 to surely perform the transition processing to the upper hierarchy, all the nodes N included in the map file CF of the upper hierarchy must have their child units C
It must be possible to search from each node N of U without fail.

Conventionally, in order to realize such a search,
A method has been adopted in which the node number, offset address, and the like of the node N of the upper layer are recorded in the node record to indicate the same position as the node N of the lower layer. However, if information relating to the internal data structure of such a higher-level map file is recorded in a lower-level map file, if the upper-level map file is updated, the lower-level map file must be updated. In addition, there is a problem that the transition process from the lower hierarchy to the upper hierarchy cannot be performed smoothly. Therefore, in the present embodiment, information that directly relates to the internal data structure of the map file CF of the upper hierarchy is not recorded in each map file CF, and the coordinate information of the node and the attribute information of the link are used when performing the hierarchy transition. Is referred to. However, in this case, generally, the map represented by the map file CF in the upper hierarchy has lower coordinate resolution than the map represented by the map file CF in the lower hierarchy. Therefore, FIG.
As shown in FIG. 0, two nodes N having different coordinates in the lower hierarchical map file and the upper hierarchical map file CF may have the same coordinate due to a rounding error of the coordinates in the upper hierarchical map file CF. . Therefore, it is not possible to uniquely specify the node N in the upper hierarchy that matches the node N in the lower hierarchy only by the node coordinates.

Therefore, in the present embodiment, not only the node coordinates but also the recording order (arrangement) of the node records NR is used. That is, as described above, the order of arrangement of the node records NR in the first or second node table is clearly defined for both adjacent nodes and non-adjacent nodes. For this reason, even in the unit U in the upper hierarchy where a rounding error occurs, the node records NR are recorded in ascending order of the coordinates using the normalized longitude / latitude coordinates before the rounding error occurs. Thereby, the data processing unit 13
When searching for a node N that is in the same position and included in the parent unit PU of the higher hierarchy from the node N of the lower hierarchy, the parent unit of the node N recorded in the lower hierarchy unit U is also searched. Based on the recording order of the node records NR, the corresponding node N in the parent unit PU is selected from the nodes N that are also recorded in U and are considered to have the same coordinates when a rounding error occurs in the upper layer. Can be uniquely identified.

More specifically, as described above, in the map file CF, the parent unit PU, which is relatively one level higher, has a unit width eight times as large as the child unit CU in both the longitude and latitude directions. . On the other hand, regardless of the hierarchy, each node has normalized coordinates normalized to 8000h (16 bits) in both the longitude and latitude directions of the unit U. That is, the parent unit PU is the child unit C
It can be said that the coordinate resolution of U is 1/8 in both the longitude and latitude directions. Therefore, the node N whose upper 13 bits have the same value in the normalized longitude and the normalized latitude coordinates of the child unit CU is 16 bits.
The parent unit PU has the same normalized coordinates.

For example, as shown in FIG. 41, five nodes Na, Nb, Nc,
Of the 16 bits of the normalized longitude and latitude coordinates of Nd and Ne, the upper 13 bits have the same value, and the nodes Na2, Nc2, which are the parents of four nodes Na, Nc, Nd, Ne, among them. It is assumed that Nd2 and Ne2 are recorded in the parent unit PU (a flag or code indicating that a parent node PU exists is recorded in each node record NR). In this case, as shown in FIG. 42, the node table of the child unit CU includes the node N
The five node records NR of a, Nb, Nc, Nd, and Ne are represented by N
The information is recorded in the order of a → Nb → Nc → Nd → Ne. At this time, the nodes Na, Nb, Nc, Nd and Ne
Are not always continuous in the node table.

When the node table of the parent unit PU is created, the parent nodes Na2, Nc2, Nd2 and Nd2 corresponding to the nodes Na, Nc, Nd and Ne are based on the order of arrangement of the five node records NR. Ne
The second node record NR is recorded in this order (not necessarily continuously recorded). As a result, as described below, the node N recorded in the child unit CU
The parent node Nd2 in the parent unit PU for d can be specified. First, the node Nd of the child unit CU has its normalized coordinates 1 in the node table.
The upper 13 bits of the 6 bits are the same node N, and are recorded in the third node record NR among the parent nodes N. Next, the normalized coordinates of the parent unit PU are calculated from the normalized coordinates of the node Nd in the child unit CU. Next, a node N having the calculated normalized coordinates is found from the node table of the parent unit PU. As a result, in the examples of FIGS. 41 and 42, four nodes Na2, Nc2, Nd2 and Ne2
Is detected. Next, as described above, the parent node Nd corresponding to the node Nd of the child unit CU is to be recorded in the third of the four nodes Na2, Nc2, Nd2, and Ne2, so that the node Nd It can be seen that the parent node of is Nd2.

As described above, after shifting to the upper hierarchy, the data processing unit 13 repeats the processing from step S103 to step S108 in the upper hierarchy, and
When the search on the side and the search on the destination DP side are connected, the route search process ends.

As described above, the map data used in the present invention is filed in units of units separated by rectangular areas, and each of these units exists in the upper and lower layers even between adjacent units in the same layer. Since record numbers and recording addresses related to the internal data structure in other units are not recorded at all between parent and child units, map data can be replaced by replacing unit files in any range and any hierarchy. Can be updated flexibly.

"Map file CF transmission / reception processing"
A system for providing a map from the center station 2 to the terminal device 1 is being researched and developed. With such a system, the terminal device 1 can obtain a necessary map when necessary. Therefore, the second storage device 24 of the center station 2 generally stores the first database 11 of the terminal device 1 side.
A second database 25 larger than one is prepared. In the present embodiment, some map files CF are managed in the first database 111 and the second database 25 by the file system described above. Then, as described below, the center station 2 and the terminal device 1 transmit and receive the map file CF.

First, the terminal device 1 requests the center station 2 to transmit the map file CF. FIG. 43A is a flowchart showing a processing procedure when the terminal device 1 requests the center station 2 to transmit a certain map file CF. FIG. 43B is a diagram showing a format of a request REQ as control data transmitted by the processing procedure of FIG. 43A. The user of the terminal device 1 has the first storage device 19
In order to add a new map file CF or to update an old map file CF to a new one, the input device 11 is operated to activate a map request / reception function. Next, the user operates the input device 1 while following a menu screen displayed on the display of the output device 110.
Operate 1 to set the required map range and hierarchy (level)
Enter The input device 11 responds to a user input by inputting information indicating a map range and a hierarchy to the data processing unit 1.
3 is specified (step S401). Here, when inputting the range of the map, the user designates a desired range of the wide-area map displayed on the display by enclosing the area with a rectangular area using the input device 11, or specifies the area using the address index. Is specified by the input device 11.

When the range and hierarchy information output from the input device 11 is input, the data processing unit 13 converts the range information into longitude and latitude coordinates. Data processing unit 13
Sends the longitude / latitude coordinates and hierarchy information to the request generation unit 14
Output to The request generation unit 14 generates a request REQ in the format shown in FIG. 43B using the input longitude / latitude coordinates and hierarchy information (step S40).
2). In FIG. 43 (b), the request REQ includes information indicating the hierarchy of the map file CF required by the user, and longitude / latitude coordinates specifying the map range represented by the map file CF. Where the longitude and latitude coordinates are
More specifically, when the user designates a wide area map by enclosing it in a rectangular area, the map includes lower left longitude coordinates, lower left latitude coordinates, upper right longitude coordinates, and upper right latitude coordinates. Request generation unit 1
4 outputs the generated request REQ to the first transmission / reception unit 15, and the first transmission / reception unit 15 transmits the input request REQ to the uplink UL via the antenna 16 (step S403).

Next, the map file CF in the center station 2
Will be described. The request REQ sent from the terminal device 1 is received by the second transmission / reception unit 21 of the center station 2 via the uplink UL of the communication network 3. The second transmission / reception unit 21 outputs the received request REQ to the reception request analysis unit 22. Here, FIG. 44 is a flowchart showing a processing procedure executed by the center station 2 after receiving the request REQ. The reception request analysis unit 22 analyzes the input request REQ, reads out the analysis result, and reads out the analysis result.
Output to 3. The read control unit 23 stores the map file CF specified by the analysis result in the second database 25.
(Step S501). Here, the request RE
In Q, the hierarchy (level) of the map file CF requested by the terminal device 1 and the lower left longitude coordinate, lower left latitude coordinate, upper right longitude coordinate, and upper right latitude coordinate of the map represented by the map file CF are described. Therefore, the reception request analysis unit 22 first extracts the lower left longitude coordinate and the lower left latitude coordinate from the request REQ, and uses the lower left longitude coordinate and the lower left latitude coordinate as representative points according to the processing procedure shown in the flowchart of FIG. The path name of the map file CF is derived.

Next, the reception request analysis unit 22 checks whether or not the map file CF having the derived path name is stored in the second storage device 24 (Step S502).
If the map file CF is not stored, the center station 2
Ends the processing in FIG. On the other hand, when the map file CF is stored, the read control unit 23 receives the path name derived by the reception request analysis unit 22, and reads the requested map file from the second storage device 24 according to the path name. Read CF. The read control unit 23 transfers the read map file CF to the memory of the packet assembling unit 25. Thereby, the packet assembling unit 25 reads the requested map file CF into the inside (step S503). The packet assembling unit 25 assembles the packet P based on the read map file CF (Step S504), and outputs the packet P to the second transmitting / receiving unit 21. The second transmission / reception unit 21 transmits the input packet P to the downlink DL (Step S505). The details of step S504 will be described later.

When step S505 is completed, the reception request analysis unit 22 determines in step S501 in the previous step S501 whether the map file CF in the range specified by the request REQ further exists in the second database 25. The longitude width W and the latitude width H at the level specified by the request REQ are added to the designated representative point coordinates, and the added value is set as a new representative point. Further, the reception request analysis unit 22
Requires the longitude and latitude coordinates of the new representative point
It is determined whether or not the upper right longitude coordinate and the upper right latitude coordinate specified by Q are exceeded. If the longitude coordinates and the latitude coordinates of the new representative point do not exceed the upper right longitude coordinates and the upper right latitude coordinates, the center station 2 continues to perform step S50.
2 to S505 are executed, and the packet P assembled on the basis of another map file CF is transmitted to the terminal device 1. If the longitude coordinates and the latitude coordinates of the new representative point exceed the upper right longitude coordinates and the upper right latitude coordinates, it is determined that all the requested map files CF have been transmitted to the terminal device 1, and the center station 2 ends the processing in FIG. . By repeating the above steps S501 to S505, the center station 2 can transmit the map file CF representing the map of the level and the range requested by the terminal device 1 to the terminal device 1.

Here, FIG. 45 shows the structure of each data in the process until the packet P is assembled from the map file CF. At the end of step S503, the inside of the packet assembling unit 25 is as shown in FIG.
As shown in (1), one map file CF is read. The packet assembling unit 25 executes Step S504. Here, FIG. 46 is a flowchart showing the detailed processing procedure of step S504. Hereinafter, FIG.
The processing of the packet assembling unit 25 will be described in detail with reference to FIG. 46 and FIG. First, the packet assembling unit 25
Creates the master data MD based on the map file CF loaded therein (step S601). The master data MD is composed of a data header DH and a data part as shown in FIG. FIG. 47 shows a detailed internal data structure of the master data MD. FIG.
In, the data header DH is composed of a unit ID and a version code. The unit ID is a code for specifying the map file CF on which the master data MD is based. The version code is a code representing the format version and the content version of the map file CF that is the basis of the master data MD. Note that both the unit ID and the version code are information stored in the unit header (see FIG. 7) of the map file CF. Will be retained. The unit ID and the version code are used in processing of the terminal device 1 described later.

The map file CF itself is set in the data section of the master data MD. Incidentally, the map file CF is composed of various tables as described above (see FIG. 7). Each of these tables has
Information that refers to another table is not recorded.
In other words, the terminal device 1 can use each table independently. For example, as shown in FIG.
The terminal device 1 outputs only the basic background table to the output device 110.
Can be displayed. That is, each table has a data structure that can be separated from each other. Therefore, the data section may be composed of only the basic data of the basic background table, the basic character / symbol table, the main road node table, and the main road link table (that is, data representing a rough map). In addition, the data section may be composed of only the detailed data of the detailed background table, the detailed character symbol table, the narrow street node table, and the narrow street link table.
As described above, a part of the map file CF may be set in the data part.

As shown in FIG. 7, the unit header includes a unit ID and a version code. The unit ID and the version code are included in the data header DH (see FIG. 47). Therefore,
When a unit ID and a version code are set in the data section of the master data MD, the master data MD includes two unit IDs and a version code. Therefore, this data part contains the unit ID
And the version code need not be included.

The packet assembling section 25 divides the master data MD generated as described above into i pieces. Thereby, as shown in FIG. 45C, i segment data SD1 to SDi are generated.
2). In this step S602, the packet assembling unit 25 is unaware of the data header DH and the data part (that is, the map file CF) included in the master data MD. That is, in any segment data SD,
It is possible that a part of the data header DH and a part of the data part are mixed. These i segment data S
A number (hereinafter, referred to as a segment number) is added to D. This segment number is preferably a continuous number that does not overlap with each other and is continuous. This is because the processing of the terminal device 1 described later becomes easy.

Further, the packet assembling section 25 adds an error correction code (or an error detection code) to the i pieces of segment data SD1 to SDi (step S60).
3). As a result, as shown in FIG. 45D, i segment data (with error correction codes) SD1 to SD
i is generated. The packet assembling unit 25 further includes each segment data (with error correction code) SD1 to SDi.
Is divided into j pieces. As a result, as shown in FIG. 45E, j packets are generated for one segment data SD (step S604). As a result of the above processing, the packet assembling unit 25 uses the one map file CF to obtain a total of i × j packets P11 and P1.
, P1j,... Pij are generated. In addition, these i
× j packets P11, P12,..., P1j,.
A number (hereinafter, referred to as a packet number) is added to j. It is preferable that the packet numbers are consecutive numbers so as not to overlap each other for each packet. This is because the processing of the terminal device 1 described later becomes easy. With this packet number, the terminal device 1
I × j packets P11, P12,
, P1j,... Pij can be easily determined. When step S604 ends, the packet assembling unit 25 exits the subroutine of FIG. 46 and returns to the process of FIG. Then, the process of step S505 is performed. , P1j,... Pij are sequentially transmitted from the second transmission / reception unit 21 to the communication network 3 (downlink DL) and transmitted to the terminal device 1 in step S505.

Next, the procedure for receiving the map file CF in the terminal device 1 will be described with reference to the flowchart in FIG. Each of the packets P11, P12,..., P1j,.
Through the antenna 16 of the terminal device 1. The first transmitting / receiving unit 15 sequentially receives the packets P11, P12, ..., P1j, ... Pij output from the antenna 16 (step S701). Also, the first transmitting / receiving unit 15
Has a buffer memory (not shown). The first transmitting / receiving unit 15 receives the received packets P11, P12,.
, Pij are sequentially stored in the buffer memory.
The packet disassembly unit 17 periodically accesses the buffer memory of the first transmission / reception unit 15 to transmit the i × j packets P11, P12,.
It is determined whether j,..., Pij are present in the buffer memory (step S702). The determination in step S702 is that each packet P11, P12,..., P1j,.
This is performed based on the packet number added to Pij.
More specifically, if the packet numbers are serial numbers, the packet decomposing unit 17 determines whether all packet numbers from 1 to (i × j) are complete.

If all packets P are not present in step S702, the packet decomposing unit 17 proceeds to step S70.
Step S701 is performed again without proceeding to step S701. As a result, the first transmission / reception unit 15 eventually receives the insufficient packet P. On the other hand, in step S702, the packet P
Are all present, the packet decomposing unit 17 proceeds to Step S703. The packet decomposing unit 17 determines in step S
, P1, the packets P11, P12,.
The master data MD is disassembled (deassembled) from j,... Pij (step S703). During step S703, error correction is also performed as necessary. The decomposed master data MD is output to the data processing unit 13. The data processing unit 13 creates a map file CF based on the input master data MD, and stores the created map file CF in cooperation with the read / write control unit 18 in the first storage device 1.
9 (step S704).

After step S704, the data processing unit 25
Determines whether there is still a series of packets P to be received (step S705). If there is a packet P to be received, the process returns to step S701, and the packet P receiving process is continuously performed. On the other hand, the packet P to be received
If not, the process of FIG. 48 ends. Here, FIG. 49 is a flowchart showing the detailed processing procedure of step S703 in FIG. FIG. 50 shows the structure of each data in the process from the packets P11, P12,..., P1j,. As is clear from the above, at the time when step S703 in FIG.
Includes a series of packets P1 as shown in FIG.
, P1,..., P1j,. The packet decomposing unit 17 stores the packets P11, P12,..., P1j,.
The packet P to be processed is obtained from ij (step S8)
01). Now, the packet decomposing unit 17 determines that the packets P11, P
12, ..., P1j.

Next, the packet decomposing unit 17 determines in step S
The packet number is removed from each packet P obtained in 801. The packet decomposing unit 17 collects the unnumbered packets P and restores one segment data SD as shown in FIG. 50B (step S80).
2). According to the above assumption, packets P11, P12,
, P1j are grouped together, and as a result, the segment data SD1 is restored. An error correction code (or error detection code) is added to each segment data SD. After step S802, the packet decomposing unit 17
An error that may have occurred in the restored segment data (with error correction code) SD is corrected using the error correction code (step S803). Next, the packet decomposing unit 17 outputs the segment data (with error correction code) S
The error correction code is removed from D.
As shown in (c), the segment data (no error correction code) SD is restored (step S804). The restored segment data SD is held in the storage area of the packet decomposing unit 17. According to the above assumption, after error correction is performed on the segment data SD <b> 1, the segment data SD <b> 1 is stored in the storage area of the packet decomposing unit 17.

After step S804, packet decomposing unit 17 determines whether or not packet P to be processed remains in first transmitting / receiving unit 15 (step S80).
5). If there is a packet P to be processed, the packet decomposing unit 17 returns to step S801 and returns to step S801.
By performing steps 801 to S804, the segment data SD is restored from the packet P as shown in FIGS. In the present description, there are (i × j) packets P in the first transmission / reception unit 15 at the start of the processing in FIG.
Therefore, the loop composed of steps S701 to S705 is repeated i times. As a result, i segment data SD1 to SDi are restored. When this loop is repeated the required number of times, there is no packet P to be processed in the first transmitting / receiving unit 15. In this state, if the determination in step S805 is made, the packet decomposing unit 1
7 proceeds to step S806. Packet P to be processed
At the time when the number of segment data SD1
SDi is held in the packet decomposing unit 17. Further, as described above, each of the segment data SD1 to SDi includes
The segment number is assigned. Packet disassembly unit 17
Are segment data SD1 to SDi according to the segment number, that is, so that the segment numbers are continuous.
In order. Thereafter, the segment number is removed from each of the segment data SD1 to SDi. The packet decomposing unit 17 collects the segment data SD1 to SDi from which the segment numbers have been removed. as a result,
As shown in FIG. 50D, the master data MD is restored (Step S806). Restored master data M
D is output to the data processing unit 13 (step S80).
7).

Note that a communication failure may occur in the communication system, not limited to the present map providing system. Therefore, the terminal device 1 cannot always correctly restore all the segment data SD. Here, the correctly restored segment data SD means the same segment data SD generated by the center station 2. For example, it is assumed that the segment data SD2 is not correctly restored and the other segment data SD1, SD3 to SDi are correctly decoded. In such a case, the packet decomposing unit 17 uses the error correction code added to the segment data SD1, SD3 to SDi to generate the segment data S1.
D2 can be restored to the correct one.

The data processing section 13 starts step S704 due to the input of the master data MD. This step S704 is, as described above, performed in the master data MD
And a process for storing the created map file CF in the first storage device 19. Here, FIG. 51 corresponds to step S7 in FIG.
14 is a flowchart illustrating the detailed procedure of the process of FIG.
First, the data processing unit 13 receives the input master data M
The unit ID is extracted from the data header DH of D (step S901). As described above, the unit ID is
It is provided so that it can be mutually converted with the path name of the unit. The data processing unit 13 outputs the extracted unit I
From D, the path name of the map file CF in the master data MD is derived.

The data processing unit 13 determines whether or not the map file CF having the path name derived in step S902 has already been stored in the first storage device 19 (step S903). If not stored, the data processing unit 13 removes the data header DH from the master data MD to obtain the map file CF. And
The data processing unit 13 reads and writes the derived path name and the currently received map file CF.
Transfer to The read / write controller 18 determines the map file C received this time according to the transferred path name.
F is stored in the first storage device 19. As a result, the new map file CF is stored in the first database 111.
Will be added.

On the other hand, in step S903, the map file CF having the path name derived in step S902
Will be described in the case where it is determined that the file already exists in the first storage device 19. In this case, the data processing unit 13 proceeds to step S904,
The version code stored in the data header DH is extracted. Further, the data processing unit 13 reads the map file CF having the path name derived in Step S902 from the first storage device 19 in cooperation with the read / write control unit 18. The data processing unit 13 extracts the version code recorded in the unit header of the map file CF read from the first storage device 19, and compares it with the version code extracted in step S904. When it is determined that the version code extracted from the master data MD is newer, the data processing unit 13 proceeds to step S906, extracts only the data portion of the master data MD, and stores the new version of the map file CF in the first file. 1 storage device 19 . As a result, in the first database 111, the old map file CF is updated to a new one.

Conversely, if the data processing unit 13 determines that the map file CF read from the first storage device 19 is newer, it discards the received master data MD. That is, the map file CF received this time is not stored in the first storage device 19. As described above, the map file CF according to the present embodiment is generated by dividing a plurality of scaled maps into units and converting them into digital data. The recording area (logical area) of each map file CF is represented by a path name specified by a tree structure representing the parent-child relationship and the adjacent relationship. Thereby, each map file CF is efficiently managed. by this,
Since information relating to the data structure of another unit is not recorded in one unit U, the relationship between the plurality of units U is reduced. As a result, even when one certain map file CF is updated, it is not necessary to update other map files CF. As described above, according to the map file CF according to the present embodiment, the process of newly storing and updating the map file CF in the first storage device 19 is greatly simplified.

Further, in such a map file CF, when following the connection of the road network over the boundary of the unit U adjacent to each other, the data processing unit 13 uses the coordinate information of the escape node and the entry node, and / or The attribute information of the exit link and the entrance link is referred to. That is, the data processing unit 13 does not refer to information related to the internal data structure of the adjacent unit NU, such as the record number or offset address of the node N or link L recorded in the adjacent unit NU. Therefore, even when one map file CF in the first storage device 19 is updated, the map file CF of the adjacent unit NU is updated.
Map files C adjacent to each other without updating
The connection of the road network of F can be accurately traced.

Further, in this embodiment, when following the connection of the road network across the boundary between a certain unit U and an adjacent unit NU, it is necessary to search for an entry node and an entry link on the adjacent unit NU side. However, in each unit U, the arrangement of the node records NR and the link records LR is defined in advance. As a result, it is possible to speed up the search process for the entry node and the entry link.

In the present embodiment, in the route search processing, the data processing unit 13 may search for a node N having the same position as a lower-level node N from the upper-level map file CF. In this case as well, between the upper and lower hierarchical units U, information relating to the internal data structure of the parent unit PU is not recorded on the child unit CU side, and information relating to the internal data structure of the child unit CU is recorded on the parent unit PU side. Information is not recorded,
Even when only the map file CF in the upper hierarchy is updated, there is no need to update all the map files CF representing the child units CU.

As described above, even when only the map of a partial area is updated to a new one such as the unit U, data consistency between adjacent units and between upper and lower layers is maintained. Therefore, even when the center station 2 provides the terminal device 1 or the like with the wired or wireless map file CF, only the map file CF required by the terminal device 1 can be transmitted. by this,
This leads to a reduction in data transmission time and communication cost.

The above embodiment has been described assuming a car navigation system as an example of the terminal device 1. However, the present embodiment can also be applied to a case where a database of the map file CF is created in the personal computer, and the personal computer displays a map or performs a route search. That is, the present embodiment can be applied not only to a mobile terminal device but also to a stationary terminal device. Also,
For a stationary terminal device, the communication network 3 does not need to be a wireless transmission path, but may be a wired transmission line.

In the present embodiment, the terminal device 1 performs two-way communication with the center station 2 through the communication network 3 to notify the center station 2 of the range of the map required by the user, and The received map file CF has been received. However, the center station 2 may transmit the map file CF to the terminal device 1 in a broadcast format.

In the present embodiment, the first database 111 and the second database 25 are composed of a map file CF having a four-level hierarchical structure of levels “0” to “3”. However, the first database 111 and the second database 25 are not limited to four layers, and may include any number of layers of the map file CF. Further, in this embodiment, each hierarchical map is divided at equal intervals in the longitude direction and the latitude direction, thereby forming a rectangular area (unit U). However, each hierarchical map may be divided at various intervals in the longitude direction and the latitude direction so that the data amount of the map file CF of each hierarchy is substantially constant. However, in this case, it is necessary to add information for specifying the division size along the longitude direction and the latitude direction to each map file CF.

Also, in the present embodiment, the map file CF
Was created in units of U. However, the map file CF may include a plurality of units U and management information for managing the plurality of units U. In this case, in order to ensure the ease of updating the map file CF, the number of units U to be combined in one map file CF is up to about 64, and the management information for managing the combined units U is complicated. It is desirable to avoid this.

Also, in one map file CF,
The node records NR of the adjacent nodes may be recorded in an order so as to go around the boundary of the unit U. Now, as an example of the recording order, the node record NR of the adjacent node
Is recorded in a clockwise order from the lower left corner of unit U. Under this assumption, the node record NR of the adjacent node included in the unit U1 shown in FIG.
Is "N10" → "N11" → "N12" → "N13"
→ "N14" → "N15" → "N18" → "N17" →
Recording is performed in the order of “N16” → “N20” → “N19”. The node record NR of the adjacent node included in the unit U3 is “N30” → “N31” → “N3
2 "→" N34 "→" N33 "→" N38 "→" N3 "
7 "→" N36 "→" N35 ". Further, the node record NR of the adjacent node included in the unit U2 is “N20” → “N21” → “N2
2 "→" N23 "→" N24 "→" N25 "→" N2 "
7 "→" N26 ". Now, as a specific example, a case will be described where the data processing unit 13 searches for the adjacent nodes N37 and N38 corresponding to the adjacent nodes N14 and N15. As described above, in the map file CF of the unit U1, the adjacent node N14 → N15
, The node records NR are recorded. On the other hand, in the map file CF of the unit U3, the adjacent node N38 → N
The node records NR are recorded in the order of 37. Therefore, if the data processing unit 13 can find the adjacent node N37 corresponding to the adjacent node N14, the adjacent node corresponding to the adjacent node N15 is recorded immediately before the node record NR of the adjacent node N37. Therefore, the data processing unit 13 can quickly find an adjacent node corresponding to the adjacent node N15. As described above, since the node records NR of the adjacent nodes are recorded in such an order as to go around the boundary of the unit U, the adjacent nodes arranged on the boundary between a certain unit N and the adjacent unit are
Since the map files CF are continuously arranged in the reverse order, the data processing unit 13 can quickly find an adjacent node of an adjacent unit corresponding to an adjacent note of a certain unit.

[Second Embodiment] FIG. 52 shows the configuration of a map providing system according to a second embodiment of the present invention. The map providing system includes a center station 101 and a terminal device 10.
2 are accommodated. The center station 101 and the terminal device 102 are connected by a wireless transmission path 103. Wireless transmission path 10
3, at least a downlink from the center station 101 to the terminal device 102 is formed. The center station 101 includes a map server 1011 and an antenna 1012. The map server 1011 includes a first storage device 1013, a read control unit 1014, and a packet assembling unit 1015.
And a transmission unit 1016. The terminal device 102 is typically a car navigation system, and includes an antenna 1021, a receiving unit 1022, and a packet disassembling unit 10
24, a data processing unit 1023 including a file management unit 1025, and a second storage device 1026.

Next, the configuration of the center station 101 will be described.
One or more map files CF that can be provided to the terminal device 102 are stored in the first storage device 1013. Details of the map file CF will be described later. First storage device 1013
Is typically a hard disk drive, CD-RO
M drive or DVD-ROM drive. The read control unit 1014 reads a part of the map file CF from the first storage device 1013 as necessary as map data CD to be provided to the terminal device 102. Details of the map data CD will be described later. The read map data CD is output to the packet assembling unit 1015.

The packet assembling section 1015 assembles (assembles) the packet P based on the input map data CD. Detailed processing of the packet assembling unit 1015 and the format of the packet P will be described later. The assembled packet P is output to the transmitting unit 1016. The transmitting unit 1016 transmits the input packet P to the antenna 101
2, the map data CD is transmitted as a packet P to the terminal device 102.
Sent to. Transmitter 1016 and antenna 1012
Is typically realized by a mobile communication device such as a mobile phone or a broadcasting device such as terrestrial digital broadcasting or satellite digital broadcasting.

Next, the configuration of the terminal device 102 will be described. The receiving unit 1022 receives the packet P transmitted by the center station 101 via the wireless transmission path 103. The antenna 1021 and the receiving unit 1022 are typically realized using a mobile communication device such as a mobile phone or a receiving device such as digital terrestrial broadcasting or digital satellite broadcasting. Receiving section 1022 outputs received packet P to packet decomposing section 1024. The packet decomposing unit 1024 decomposes (deassembles) the input packet P and restores the map data CD. The restored map data CD is output to the file management unit 1025.
The file management unit 1025 stores the input map data CD
Is processed according to a predetermined procedure. The procedure of this processing will be described later. By this processing, the map file CF
Is created. The map file CF has the same structure as the map file CF map data on the center station 101 side.
Details of the map file CF will be described later. The second storage device 1026 is readable and writable, and has a large-capacity storage medium. The second storage device 1026 is typically configured by an HDD and a DVD-RAM drive. The map file CF generated by the file management unit 1025 is written on this storage medium. Also,
As is well known, the second storage device 1026 manages a storage area in cluster units.

The data processing unit 1023 performs various processes (eg, route search, map matching, or route guidance) in addition to the above-described decryption and file management. Further, the data processing unit 1023 extracts a part of the map file CF from the second storage device 1026 as necessary, and outputs it to an output device described later. In addition, the terminal device 1
02 includes an input device and an output device in addition to the illustrated configuration. However, these processes, the input device and the output device are not the points of the present invention and are not described in detail,
Also not shown. The input device and the output device will be briefly described. The input device is operated by the user of the terminal device 102. The user requests the terminal device 102 to scroll the map or change the scale through the input device. The output device mainly includes a display and a speaker. A map is displayed on the display as needed. Further, the result of the route search process or the route guidance process performed by the data processing unit 1023 may be displayed on the display. The speaker provides the result of the route guidance processing performed by the data processing unit 1023 to the user by voice.

Next, referring to FIG. 53, each map file
The structure of the CF will be described. First, as shown in FIG.
The map α of a certain range has a predetermined shape (this embodiment
In this example, M × N (M and N are assumed to be rectangular for convenience)
N is an arbitrary natural number) and is divided into units U_0,0 
~ U_{M-1, N-1}Is created. Unit U_0,0~ U_{M-1
, N-1}Are each converted to data, and the unit data UD_0,0
 ~ UD_{M-1, N-1} Is generated. Unit data UD_0,0
 ~ UD_{M-1, N-1} Is the unit record UR described later_0,0
 ~ UR_{M-1, N-1} A part of. Map file CF
Means each unit U _0,0 ~ U_{M-1, N-1} Created based on
Stored in a predetermined address area of the first storage device 1013.
You.

Each map file CF has a file header FH and unit management information MI as shown in FIG.
_UNIT and M × N unit records UR _{0,0 to} UR
_{M-1, N-1} . In the file header FH,
Information for specifying the range covered by the map file CF (map α) is described. More specifically, the file header FH contains the minimum latitude LAT _MIN and longitude LON
_MIN , maximum latitude LAT _MAX and longitude LON _MAX , latitude
Actual distance D _{LAT in} degrees and actual distance D _{LON in} longitude
And Where LAT _MIN , LON _MIN , LAT
_MAX and LON _MAX are, as shown in FIG.
The minimum latitude , minimum longitude , maximum latitude and maximum longitude of the map α are shown. Further, D _LAT and D _LON indicate actual distances in the latitude and longitude directions of the map α as shown in FIG. 53 (a). Thus, LAT _MIN , LON _MIN , L
AT _MAX , LON _MAX , D _LAT , and D _LON define the range covered by the map file CF (that is, map α). In the unit management information MI _UNIT , information for managing each of the unit records UR _{0,0 to} UR _{M-1, N-1} is described. More specifically, the unit management information MI _UNIT
Is the number NOU of unit records included in the map file CF, and the offset value X _{0,0-
XM-1, N-1} . Here, NOU is a value of M × N. The offset values X _{0,0 to} X _{M−1, N−1} correspond to the first address (first address) where the map file CF is stored.
From the storage position in the storage device 1013) to the head address where the unit records UR _{0,0 to} UR _{M-1, N-1} are stored. FIG. 53B illustrates an offset value X _0,0 of the unit record UR _0,0 .

Each unit record UR _{0,0 to} UR
_{M-1, N-1,} based on the address specified by the offset value X ₀ ~X _N-1 of the unit management information MI _UNIT,
It is stored in the storage medium of the first storage device 1013. The unit records UR _{0,0 to} UR _{M-1, N-1} are shown in FIG.
As the 4, including unit data _{U D 0,0 ~U D M-1} , N-1. Furthermore, each unit data _{U D 0,0 ~U D M-1} , N-1
Are added with unit headers UH _{0,0 to} UH _{M-1, N-1} . Thereby, each unit record UR _{0,0 to} U
_{RM-1, N-1} are configured. Hereinafter, each unit record U
To specifically explain R, the unit record UR
_{Take 0,0} as an example. First, unit data UD _0,0
Is a data of one of the areas defined by the map α as shown in FIG. 53, and the corresponding unit U _0,0
Is the actual data making up the map of the area represented by. Hereinafter, for the sake of clarity, the map of the area represented by the unit U _0,0 is referred to as a map β _0,0 . Unit data UD _0,0
More specifically, the map β _0,0 is composed of background data BD _0,0 , character / symbol data CD _0,0 , and road network data ND _0,0 .

The background data BD _0,0 is graphic data for displaying rivers, railways, green belts, buildings, bridges, and the like on the map β _0,0 . As shown in FIG. 54, the background data BD _0,0 is composed of a basic background data table BBD _0,0 and a detailed background data table DBD _0,0 . As shown in FIG. 55 (a), the basic background data table BBD _0,0 includes graphics for displaying basic elements (that is, background) on the map β _0,0 , such as rivers, railways, and green belts. The data is recorded. The detailed background data table DBD _{0, 0,}
In order to display the basic background of the map β _0,0 in more detail, graphic data of buildings, bridges, etc. are recorded as shown in FIG.

In addition, the basic background data table BBD _0,0
The detailed background data tables DBD _0,0 have independent structures as shown in FIG. As a result, the center station 101 and the terminal device 102 can separate and use the basic background data table BBD _0,0 and the detailed background data table DBD _0,0 independently. That is, the terminal device 102 can display the basic background data table BBD _0,0 alone as shown in FIG. Furthermore, the terminal device 102
As shown in (c), the detailed background data table DBD _0,0 can be superimposed and displayed on the basic background data table BBD _0,0 . In addition, the background of the map β _0,0 is configured by superimposing what is displayed by the basic background data table BBD _0,0 and what is displayed by the detailed background data table DBD _0,0 . In other words, from a different point of view, the detailed background data table DBD _0,0 is the background data BD _0,0
And the basic data table BBD _0,0 .

The character / symbol data CD _0,0 corresponds to the map β
_This is data representing a character string on _0,0 and / or a map symbol. With the character symbol data CD _0,0 , place names, road names, facility names, map symbols, and the like are displayed on the map β _0,0 . The character symbol data CD _0,0 is, as shown in FIG.
It comprises a basic character / symbol data table BCD _0,0 and a detailed character / symbol data table DCD _0,0 . The basic character and symbol data table BCD _0,0, as shown in FIG. 56 (a), place names, road names, map symbols, etc., a map beta _0,0
Is recorded. The detailed character / symbol data table DCD _0,0 contains a map β such as the names of parks, railways, bridges and factories, as shown in FIG.
Data necessary for displaying _0,0 in detail is recorded.

The basic character / symbol data table BCD
_0,0 and the detailed character / symbol data table DCD _0,0
As shown in FIG. 54, they have independent structures. Thus, the basic character / symbol data table BCD _0,0 and the detailed character / symbol data table DCD _0,0 can be used independently. That is, the terminal device 102
However, the basic character / symbol data table BCD _0,0 is displayed alone as shown in FIG. 56 (a), or the detailed character / symbol data table BCD _0,0 is displayed as shown in FIG. 56 (c). The table DCD _0,0 can be superimposed and displayed. Further, a detailed character / symbol data table DCD _0,0
Is difference data between the character symbol data CD _0,0 and the basic character symbol data table BCD _0,0 .

Further, road network data ND _0,0
Are the background data BD _0,0 and the character symbol data CD _0,0
And data for displaying a road on the map β _0,0 . The road network data ND _0,0 may be used for map matching, route search, or route guidance. The road network data ND _0,0 is a main trunk network data table M
ND0,0 and narrow street network data table SN
D _0,0 . In the main trunk network data table MND _0,0 , as shown in FIG.
Road network data for a road having a relatively wide width (for example, 5.5 m or more), that is, a main road is recorded.
Furthermore, the main trunk network data table MND
Preferably, at _0,0 , road network data is recorded for each road type, such as expressways, general national roads, and prefectural roads. Narrow street network data table SND
_{At 0,0} , as shown in FIG. 57 (b), a road having a relatively narrow width (for example, 3.0 m or more and less than 5.5 m),
That is, road network data for narrow streets is recorded.

The main trunk network data table MND _0,0 and the narrow street network data table SND _0,0 are also the basic background data table BBD _0,0.
It has the same independent structure as the detailed background data table DBD _0,0 . Therefore, the terminal device 102
As shown in FIG. 57 (a), using the main trunk network data table MND _0,0 alone, it is possible to display only the main road. Also, the terminal device 102 is configured as shown in FIG.
As shown in (b), narrow street network data table S
It is also possible to display only narrow streets by using ND _0,0 alone. Further, as shown in FIG. 57 (c), the terminal device 102 has a main trunk network data table MND.
Used by superimposing a minor street network data table SND _0,0 to _0,0, or can display the main road and a minor street. The narrow street network data table SND _0,0 stores the road network data ND _0,0.
And the main trunk network data table MND _0,0 .

The terminal device 102 uses the main trunk network data table MND _0,0 alone or performs both the main trunk network data table and the narrow street network data table SND _0,0 at the time of map matching processing or the like. Can also be used. Also,
The main trunk network data table MND _0,0 and the narrow street network data table SND _0,0 are also used to trace the connection relationship between the main road and the narrow street.
When tracing such a connection relationship, a node indicating an intersection between a main road and a narrow street is used.

As shown in FIG. 58 (a), the basic background data table BBD _0,0 , the basic character / symbol data table BCD _0,0, and the main trunk network data table MND _0,0 are superimposed. The terminal device 10
2 can be made relatively coarse map beta _{0, 0.} On the other hand, the detailed background data table DBD _0,0 , the detailed character / symbol data table DCD _0,0 , and the narrow street network data table SND _0,0 are a coarse map β _0,0 configured as shown in FIG. 58, a more detailed map β _0,0 as shown in FIG. _58B can be constructed.

The detailed structure of the unit data UD _0,0 has been described above. Other unit data UD _0,1 , ...
UD _{0, N−1} , UD _1,0 ,... UD _{M−1, N−1} have also been described with reference to FIGS. 54 to 58 for the corresponding ranges, similarly to the unit data UD _0,0 . It has such a structure.

Also, the unit records UR _{0,0 to} UR
_{M-1, N-1} are unit headers UH _0,0 as described above.
~ UH _{M-1, N-1} . Unit header UH _{0,0 to} UH
_{M-1, N- 1} includes unit data UD _{0,0 to} UD _{M-1, N-1}
Attribute information is described. More specifically, for example, the unit header UH _0,0 includes a unit ID for specifying the unit data UD _0,0 and a basic background data table B
BD _0,0 , detailed background data table DBD _0,0 , basic character / symbol data table BCD _0,0 , detailed character / symbol data table DCD _0,0 , main trunk network data table MND _0,0 and narrow street network data table SND The size of _0,0 is described. Other unit headers UH _{0,1 to} UH _{M-1, N-1} are also unit header U
Similarly to H _0,0 , the corresponding unit data UD _{0,1 to} U
The attribute information of DM _{-1, N-1} is described. Unit header U
Each unit ID in H _{0,0 to} UH _{M-1, N-1} may be any information as long as the corresponding unit data UD _{0,0 to} UD _{M-1, N-1} can be specified. Typically, these are specified by serial numbers or longitude and latitude.

Next, the procedure for transmitting map data in the center station 101 will be described with reference to the flowchart in FIG. As described above, the first storage device 101
3, one or more map files CF (see FIGS. 53 and 54) are stored in advance. Read control unit 10
14 is stored in the first storage device 1013 as needed.
A part or all of some predetermined map files CF are read (step S1001). here,
In the present embodiment, a part of the map file CF is a file header FH, unit management information MI _UNIT, and some unit records UR constituting the map file CF.
Means On the other hand, in the present embodiment, all of the map file CF means the file header FH, the unit management information MI _UNIT, and all the unit records UR constituting the map file CF. Hereinafter, a part or all of the map files CF read by the read control unit 1014 will be referred to as map data CD. The read map data CD is developed in a storage area (typically, a RAM) in the packet assembling unit 1015.

After step S1001, the packet assembling section 1015 uses the map header CD developed in the internal storage area to transmit a file header FH and unit management information MI _UNIT (FIG. 53) necessary for transmission to the terminal device 102.
(B) and one unit record UR (FIG. 5)
3 (b)) (step S1002).

[0196] The packet assembling unit 1015, based on the unit record UR, the file header FH, and the unit management information MI _UNIT obtained in step S1002,
The packet P is assembled (step S1003). The detailed process of step S1003 will be described later. The assembled packet P is output to the transmitting unit 1016. The transmitting unit 1016 transmits the input packet P to the wireless transmission path 103 via the antenna 1012, and transmits the packet P to the terminal device 102 (step S10).
04).

After step S1004, the packet assembling section 1015 determines whether or not there is further unit data UD to be transmitted in the map data CD expanded in the internal storage area (step S1005). If there is still unit data UD to be transmitted, the packet assembling unit 1015 returns to step S1002 to obtain necessary data. On the other hand, when there is no unit data UD to be transmitted, the packet assembling unit 1015 notifies the reading control unit 1014 of the fact.

The read control unit 1014 responds to the notification from the packet assembling unit 1015 and returns to step S1001
Closes the map data CD read in step (step S1)
006). Next, the reading control unit 1014 determines whether or not there is map data CD (other than the one closed in step S1006) including the unit data UD to be transmitted to the terminal device 102 (step S100).
7). If another map data CD exists, the read control unit 1014 reads the map data CD to read the map data CD.
It returns to step S1001. On the other hand, another map data CD
If not, the center station 101 ends the series of processes shown in the flowchart of FIG.

Here, FIG.
Of each data in the process until the packet P is generated
Shows the structure. Step S1001 (see FIG. 59)
At the end of the process, the read control unit 101460
As shown in (a), the map data CD is read out.
You. At the end of step S1002, the packet
The assembling unit 1015 sends the file header FH
It holds several unit records UR. Figure 60
In (a), the unit record UR_0,0 Is retained
It is shown. Then, the packet assembling unit 1015
Executes step S1003. Here, FIG.
Is a flowchart showing the detailed processing procedure of step S1003.
It is a chart. Hereinafter, referring to FIG.
The processing of the assembling unit 1015 will be described in detail. At first,
The master data MD is transmitted by the packet assembling unit 1015.
File header FH and unit management information
Report MI_UNIT, And one unit record UR
Is generated (step S1101). In addition, master
The data MD is generated directly from the map file CF.
Rather than being held by the packet assembler 1015
It is generated based on one unit record UR. Or
By employing such a generation method, for example, FIG.
In steps S1001 to S1007,
Or if an error occurs due to internal factors,
Affects only one unit record UR
Because there is no. In other words, the effect of the error is
This is for avoiding the entire D.

The master data MD is composed of a data header DH and a data part as shown in FIG. Here, FIG. 62 shows a detailed structure of the master data MD. In FIG. 62 , the data header DH includes a file ID, a unit ID, and a unit size. The file ID is a code for specifying the map data CD (that is, the one currently developed in the packet assembling unit 1015) which is the basis of the master data MD. An example of a method for generating the file ID will be described. The packet assembling unit 1015 holds the file header FH. As described above, information for specifying the range covered by the map file CF (map α) is described in the file header FH (see FIG. 53B). Therefore, the file header FH can also specify the map file CF. The packet assembling unit 1015 generates a file ID using the file header FH. The unit ID is a code for specifying the unit record UR (that is, the one extracted in step S1002) which is the basis of the master data MD. The packet assembling unit 1015 holds the unit record UR to be transmitted (see FIG. 54) after the end of step S1002. The packet assembling unit 1015 extracts the unit ID from the held unit record UR. Unit I taken out
D is set in the data header DH. Note that the above 2
The two IDs and the unit size correspond to the terminal device 1 described later.
02 is used in the processing of FIG.

The data portion of the master data MD includes:
The file header FH and all or part of the data included in the unit record UR are set. The set file header FH and unit record UR are held by the packet assembling unit 1015.
Incidentally, various tables are held in the unit record UR as described above (see FIG. 54). Each of these tables has a structure that can be separated from each other. Therefore, the data section may be composed of only the basic data of the basic background data table BBD, the basic character / symbol data table BCD, and the main trunk network data table MND (that is, data representing a rough map). Also,
The data section may be composed of only the detailed data of the detailed background data table DBD, the detailed character / symbol data table DCD, and the narrow street network data table SND. As described above, a part of the unit record UR may be set in the data part. As shown in FIG. 54, the unit header UH includes a unit ID. This unit ID is included in the data header DH (see FIG. 62). Therefore, when the unit ID is set in the data portion of the master data MD, the master data M
D contains two unit IDs. Therefore, the data portion does not have to include the unit ID.

Incidentally, the data size of the data header DH is the size of the data part. File header FH
And the size of the entire unit record UR are determined at the time when the map file CF is generated in the first storage device 1013, and thus can be easily obtained. In the data section,
If a partial unit record UR is set,
The size of the partial unit record UR is obtained based on each size set in the corresponding unit header UH.

The packet assembling section 1015 divides the generated master data MD into i pieces. by this,
As shown in FIG. 60 (c), i segment data SD ₁
~ SD _i are generated (step S1102). In this step S1102, the packet assembling unit 101
No. 5 is unaware of the data header DH and the data part (that is, the unit record UR) included in the master data MD. That is, a part of the data header DH and a part of the data part may coexist in any of the segment data SD. These i segment data SD
, A number (hereinafter referred to as a segment number) is added. This segment number is preferably a continuous number that does not overlap with each other and is continuous. This is because the processing of the terminal device 102 described later becomes easy.

Further, the packet assembling unit 1015
i segment data SD₁ ~ SD_i And error correction
A code (or an error detection code) is added (step S1).
103). As a result, as shown in FIG.
i segment data (with error correction code) SD₁ ~
SD_i Is generated. The packet assembler 1015 is
In addition, each segment data (with error correction code) SD₁ 
~ SD_i Is divided into j pieces. As a result, FIG.
As shown in (e), one segment data SD
Then, j packets are generated (step S110).
4). As a result of the above processing, the packet assembling unit 1015
Is one unit extracted in step S1002
Based on the record UR, a total of i × j packets P₁₁,
P₁₂, ... P_1j, ... P_ijGenerate Also, these i × j
Packets P₁₁, P₁₂, ... P_1j, ... P _ijEach
And a number (hereinafter referred to as a packet number) is added.
This packet number does not overlap with each other for each packet.
It is preferred that the numbers be consecutive. Why
Because the processing of the terminal device 102 described later becomes easier.
is there. With this packet number, the terminal device 102
I × j packets P transmitted individually₁₁, P₁₂…
P_1j, ... P_ijBut it is easy to judge whether all
I will be able to. Step S1104 ends.
The packet assembling unit 1015 is a subroutine.
61, and returns to the processing of FIG. Soshi
Step S1004 is performed. Each packet P
₁₁, P₁₂, ... P_1j, ... P _ijIs entered in step S1004.
From the transmitting unit 1016 through the antenna 1012
The data is sequentially transmitted to the wireless transmission path 103 and transmitted to the terminal device 102.
Be trusted.

Next, referring to the flowchart of FIG.
The procedure for receiving map data in the terminal device 102 will be described.
Will be described. Each packet P transmitted by the center station
₁₁, P ₁₂, ... P_1j, ... P_ijThrough the wireless transmission path 103
The signal is input to the antenna 1021 of the terminal device 102.
Receiving section 1022 transmits a signal output from antenna 1021.
Kett P₁₁, P₁₂, ... P_1j, ... P_ijSequentially
Step S1201). The receiving unit 1022 is illustrated in FIG.
No buffer memory. The receiving unit 1022 receives
Each packet P₁₁, P₁₂, ... P_1j, ... P_ijThe
Sequentially stored in memory.

[0206] The packet decomposing unit 1024
2 periodically accesses the buffer memory of the center station
I × j packets P transmitted by 101₁₁,
P₁₂, ... P_1j, ... P_ijAre aligned in the buffer memory
It is determined whether it is (Step S1202). Step S
The judgment at 1202 is that each packet P₁₁, P₁₂, ... P_1j…
P _ijThis is performed based on the packet number added to. Yo
More specifically, if the packet number is a serial number,
The decomposing unit 1024 calculates the packet number from 1 to (i × j).
It is determined whether or not all the items are present.

If not all packets P are found in step S1202, packet decomposing section 1024 does not proceed to step S1203, and step S1201 is executed again. As a result, the receiving unit 1022 receives the insufficient packet P. On the other hand, in step S1202, when all the packets P are collected, the packet decomposing unit 1024
Proceed to step S1203. Packet decomposition unit 1024
Are the packets P ₁₁ , P ₁₁ received in step S1201
_12, ... P _1j, ... by decomposing P _ij, to restore the master data MD (step S1203). The restored master data MD is output to the file management unit 1025. The file management unit 1025 generates a map file CF based on the input master data MD. The generated map file CF is stored in the second storage device 1026 (Step S1204).

After the step S1204, the data processing unit 1
No. 023 determines whether there is still a series of packets P to be received (step S1205). If there is a packet P to be received, the process returns to step S1201, and the packet P receiving process is continued. On the other hand, when there is no packet P to be received, the processing in FIG. 63 ends.

Here, FIG. 64 is a flowchart showing step S1 in FIG.
4 is a flowchart illustrating a detailed processing procedure of step 203. FIG. 65 shows packets P ₁₁ , P ₁₂ ,... P _1j,.
The structure of each data in the process from _Pij to generation of the map file CF is shown. As is clear from the above, at the time when step S1203 in FIG. 63 is started, the receiving unit 1022 outputs
Series of packets _{P 11, P 12, ... P} 1j, ... P ij are aligned. Packet decomposition unit 1024, receiving unit packet P ₁₁ held in _{1022, P 12, ... P 1j} , from ... P _ij,
A packet P to be processed is obtained (step S1301).
Now, the packet decomposer 1024 outputs the packets P ₁₁ , P ₁₂ ,.
Suppose we get P _1j .

Next, the packet decomposing unit 1024 removes the packet number from each packet P obtained in step S1301. The packet decomposing unit 1024 decomposes each of the unnumbered packets P, as shown in FIG.
One segment data SD is restored (step S13)
02). According to the above assumptions, packets P ₁₁ , P ₁₂ ,.
P _1j are grouped together, and as a result, the segment data S
D ₁ is restored. An error correction code (or error detection code) is added to each segment data SD. After step S1302, the packet decomposing unit 1024 corrects an error that may have occurred in the restored segment data (with error correction code) SD by using the error correction code (step S1303). Next, the packet decomposing unit 1024 removes the error correction code from the segment data (with the error correction code) SD, thereby
As shown in FIG. 5 (c), the segment data (no error correction code) SD is restored (step S1304). The restored segment data SD is sent to the packet
24 storage areas. According to the above assumptions, after the error correction is applied to the segment data SD _1, it is held in the storage area of the packet decomposition unit 1024.

After step S1304, packet decomposing section 1024 determines whether or not packet P to be processed remains in receiving section 1022 (step S130).
5). If the packet P to be processed remains, the packet decomposing unit 1024 returns to step S1301, performs steps S1301 to S1304, and performs processing in FIG.
As shown in (c), the segment data SD is restored from the packet P. In this description, at the start of the process in FIG. 64, the receiving unit 1022 has (i × j) packets P. Therefore, the loop composed of steps S1201 to S1205 is repeated i times. As a result, i segment data SD _{1 to} SDi are restored.

When this loop is repeated the required number of times, there are no more packets P to be processed in receiving section 1022. In this state, when the determination in step S1305 is made, the packet decomposing unit 1024 determines in step S130
Proceed to 6. When there are no more packets P to process,
The i segment data SD _{1 to} SD _i are held in the packet decomposing unit 1024. As described above, each segment data SD ₁ to SD _i, the segment are numbered. The packet decomposing unit 1024 arranges the segment data SD _{1 to} SD _i in order according to the segment number, that is, so that the segment numbers are continuous. Thereafter, the segment number is stored in each segment data S
Is removed from the D ₁ ~SD _i. Packet decomposing unit 102
No. 4 puts together the segment data SD _{1 to} SD _i from which the segment numbers have been removed. As a result, FIG.
As shown in (d), the master data MD is restored (step S1306). Restored master data MD
Is output to the file management unit 1025 (step S
1307).

[0213] In addition to the present map providing system, a communication failure may occur in a communication system. Therefore, the terminal device 102 cannot always correctly restore all the segment data SD. Here, the correctly restored segment data SD means the same segment data SD generated by the center station 101. For example, in a case where the segment data SD ₂ is not correctly restored, it is assumed that other segment data SD _1, SD ₃ ~SD _i was decoded correctly. In such a case, the packet decomposing unit 1024 sets the segment data SD ₁ , SD ₃
~ SD _i using the error correction code added to the segment data SD ₂ Can be restored to the correct one.

[0214] The file management unit 1025 starts step S1204 due to the input of the master data MD. This step S1104 is a process of generating a map file CF from the master data MD, as described above,
The generated map file CF is stored in the second storage device 1026.
This is the process for storing in the. Here, FIG.
13 is a flowchart showing the detailed procedure of Step S1204 of FIG.

By the way, the second storage device 1026 may have already stored the map file CF generated before at the start of step S1204. In some cases, the map file CF is not stored. After inputting the master data MD, the file management unit 1025
It is determined whether or not the map file CF is stored in the storage device 1026 (step S1401). If there is a map file CF, the file management unit 1025 proceeds to step S1404 described below. On the other hand, if there is no map file CF, the file management unit 1025 determines that a completely new map file CF has been created based on the current master data MD.
Is created (step S1402). The map file CF has the same data structure as the map file CF (see FIGS. 53B and 54).

Here, a method of creating the map file CF will be described. As shown in FIG. 62, the master data MD
The map file ID, unit ID, and data size are included in the data header DH. Further, the master data MD has a file header FH and all or some unit records UR in the data section. The file management unit 1025 converts the file header F from the master data MD.
Take out H.

As described above, the master data MD contains 1
Only unit records UR are included. Also,
This time, the file management unit 1025
Generate a CF. Therefore, the file management unit 1025
Generates a unit number NOU with an initial value “1”. Further
In addition, the file management unit 1025 checks the file header FH
And the data size of the number of units NOU
Offset value X to the specified unit record UR_0,0 To
Ask. Thereby, the unit management information MI _UNITIs raw
Is done.

Thus, the file management unit 1025
Means that all the information necessary to generate a completely new map file CF has been obtained. File management unit 102
Reference _{numeral 5} collects the file header FH, unit management information MI _UNIT, and unit record UR obtained this time to generate a map file CF. The data structure of the map file CF is as shown in FIG. The map file CF generated as described above is stored in the second storage device 1026 (step S1403).

Next, the processing when the map file CF is found in step S1401 will be described. In this case, step S1404 is performed. The file management unit 1025 uses the master data MD input this time to
Extract the file ID. As described above, the file ID specifies which map file CF the unit record UR in the master data MD belongs to. This file ID is generated by the packet assembling unit 1015 using the file header FH of the map file CF, as described above with reference to FIG. In addition, the file management unit 1025 extracts the file header FH of each map file CF in the second storage device 1026. The file header FH specifies a range covered by the map file CF. The file header FH of the map file CF is, as described in step S1402,
It is created based on the map file CF managed by the center station 101. Therefore, if the file ID and the file header FH are the same, the unit record UR input this time constitutes a part of the map file CF. Therefore, the file management unit 1025 determines the identity of the two (step S1404).

If it is determined in step S1404 that there is no identity, it means that the map file CF including the input unit record UR as a component has not been created yet. In this case, the file management unit 1025 executes the above-described steps S1402 and S1403.
That is, after a completely new map file CF is generated, it is stored in the second storage device 1026.

On the other hand, in step S1404, the file I
If it is determined that D and the file header FH have the same identity, it means that the map file CF having the input unit record UR as a component has already been generated. In this case, the file management unit 1025 selects the map file CF as a processing target. The file management unit 1025 opens the map file CF to be processed (step S1405), and adds the input unit record UR to the map file CF selected as the processing target (step S1406). That is, step S
At 1406, the input unit record UR and the map file CF are put together to generate an updated map file CF.

Step S1406 will be described in more detail. The file management unit 1025 extracts the unit ID from the current master data MD. Thereafter, the unit ID extracted from the input master data MD
Is referred to as a first unit ID. First unit ID
As described with reference to FIG. 62, the unit record UR serving as the basis of the master data MD input this time is
To identify. The file management unit 1025 extracts all unit IDs from the map file CF opened in step S1405. Hereinafter, each unit ID extracted from the map file CF is referred to as a second unit ID. In the second unit ID, the first unit I
There is a case where a match with D is not included, and a case where a match is included.

If the first and second unit IDs do not match, the file management unit 1025 extracts the unit record UR from the currently input master data MD and is currently open as shown in FIG. In addition to the map file CF, the map file CF is updated.
If the first and second unit IDs match, the unit record UR input this time has
01, it is provided to the terminal device 102. For example, in the unit record UR having the structure shown in FIG. 54, only basic data (schematic data) such as the basic background data table BBD, the basic character / symbol data table BCD, the main trunk network data table MND, and the like at the time of step S1204 There is a case where it is already provided to the terminal device 102. In this case, the currently opened map file CF has a structure as shown in FIG. In this case, the file management unit 1025
As shown in (1), the unit record UR extracted from the currently input master data is added to the unit record UR having the same unit ID in the currently opened map file CF. As a result, the map file CF is updated.

[0224] The file management unit 1025 furthermore, according to the data size of the master data MD inputted this time,
Update the unit management information MI _UNIT (step S14)
07). Next, the file management unit 1025 stores the updated map file CF in the second storage device 1026 (Step S1408).

As described above, in the present map providing system,
The first storage device 1013 stores a map file CF. The packet assembling unit 1015 includes the terminal device 10
2 reads out only a partial map to be transmitted to the control unit 10
14 and generates a series of packets P representing the map. This series of packets P is transmitted to the wireless transmission path 103
Transmitted over. Only data representing a partial map is transmitted on the wireless transmission path 103. Therefore, the present map providing system can suppress the amount of data transmitted to the wireless transmission path 103 even if the map file CF itself has a large size. As a result, the wireless transmission path 103 is less likely to be congested.

Further, the terminal device 102 sequentially receives data representing a partial map. However, the terminal device 102 initially separates partial map data into individual files. However, the terminal device 102
When there is a map file CF that satisfies a predetermined condition, the received partial map data is added to the map file CF to combine them. Therefore, the present map providing system can suppress generation of a large number of files in the terminal device 102. Therefore, a cluster having a free area is less likely to occur in the second storage device 1026. As a result, the map providing system can effectively use the storage area of the second storage device 1026.

As shown in FIG. 53 , the map file CF is formed by dividing a map α of a predetermined range into a plurality of areas, that is, in units of units U. By unitizing the map α as described above, the read control unit 1014 can easily read a map of a necessary portion from the first storage device 1013. In addition, this unitization allows the center station 101 to communicate with the wireless transmission path 1
03 can easily transmit the optimum amount of data to the wireless transmission path 103 without congestion. Furthermore, the center station 1
Even if 01 transmits a plurality of unit records UR, the terminal device 102 may not be able to receive any of the unit records UR due to a communication error.
In such a case, the terminal device 102 creates the map file CF using the received unit record UR.
The terminal device 102 can perform various processes based on the created map file CF. That is, even if a part of the unit record UR transmitted from the center station 101 is omitted, the influence of the omission does not affect other unit records received by the terminal device 102. Such an effect is also produced by unitizing the map.

In the unit record UR,
The basic data of the map (schematic data) and the detailed data of the map are described in a plurality of independent tables. This allows each table to be used independently, even if stored in one unit record UR. That is, for example, the center station 1
No. 01, when providing a map to the terminal device 102, can transmit basic data (schematic data) alone, transmit detailed data alone, or transmit both in combination. As a result, the center station 101
It is possible to provide a map suitable for the situation and use of the terminal device 102.

For example, if the terminal device 102 wants to receive a wide area map faster than a detailed map, the center station 101 can preferentially transmit only basic data (schematic data). Further, after the terminal device 102 has completely received the basic data (schematic data), the center station 2 can transmit the detailed data. Thus, the terminal device 102 can also use the basic data (schematic data) and the detailed data in a mixed manner.

[0230] As described above, a mobile communication device can be used as the transmitting unit 1016 and the receiving unit 1022 as described above. In this case, since the two-way communication between the center station 101 and the terminal device 102 can be easily realized, the terminal device 102 sets the type of the map desired to be provided (information indicating the outline data or the detailed data) to the center station 101. Can be requested in real time. Further, as the transmission unit 1016 and the reception unit 1022, a broadcasting device such as a terrestrial digital broadcast and a device for receiving the broadcast can be used. In this case, the center station 101 allocates different channels to the basic data (schematic data) and the detailed data using different channels, thereby enabling the reception time of the basic data (schematic data) and the detailed data and the receivable time. You can adjust the range of the map.

In the above embodiment, the file header FH of the map file CF in the second storage device 1026 is used.
Has been used as it is in the map file CF on the first storage device 1013 side. That is, both map files CF cover the same range. However, the processing capabilities of the center station 101 and the terminal device 102 are often different. For example, the storage capacity of the second storage device 1026 is often smaller than that of the first storage device 1013. Therefore, the terminal device 102 may generate the map file CF covering a smaller area than the map area represented by the map file CF. That is, the terminal device 102 may generate the map file CF covering the unique range.

In the second embodiment, the terminal device 102
The above has been described assuming a car navigation system as an example. However, the present embodiment can also be applied to a case where a database of the map file CF is created in the personal computer, and the personal computer displays a map or performs a route search. That is, the technical field of the present invention can be applied not only to a mobile terminal device but also to a stationary terminal device. Further, for a stationary terminal device, the communication network 103 does not need to be a wireless transmission path, and may be a wired transmission line.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a map providing system according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a hierarchical structure of a map represented by a first map file 111 and a second map file 25 shown in FIG.

FIG. 3 is a diagram for explaining a unit U ₃ in the highest hierarchy (level “3”) shown in FIG. 2;

FIG. 4 is a diagram for describing a parent-child relationship between respective hierarchies from level “3” to level “0”.

FIG. 5 is a diagram showing a tree structure for managing a first map file 111 and a second map file 25;

FIG. 6 is a diagram showing a data structure of one unit U belonging to a certain level.

FIG. 7 is a diagram showing a data structure of a map file CF.

FIG. 8 is a schematic diagram of a map represented by background data.

FIG. 9 is a diagram for explaining the concept of a drawing object using the drawing objects BO1 and BO2.

FIG. 10 is a diagram showing a detailed data structure of a background data table.

FIG. 11 is a diagram showing graphic data composed of eight element points P0 to P7.

12 is a diagram showing a data structure when absolute coordinates P0 to P7 in FIG. 11 are described in an object record OR.

FIG. 13 shows respective element points P0 to P of the same graphic data as in FIG. 11;
FIG. 7 is a diagram when 7 is represented by relative coordinates.

FIG. 14 is a diagram showing a data structure when relative coordinates of element points P0 to P7 in FIG. 13 are described in an object record OR.

FIG. 15 is a diagram showing an object OBJ composed of element points P0, P1, and Pn.

16 is a diagram showing element points P2 and P3 supplemented on a straight line connecting element points P1 and Pn in FIG.

FIG. 17 is a diagram illustrating a data structure when relative coordinate information of element points P0, P1, P2, P3, and Pn in FIG. 16 is described in an object record OR.

18 is a diagram illustrating a data structure of an object record OR when the element points P0 and Pn in FIG. 15 are represented by absolute coordinates, and the element points P1 are represented by relative coordinates.

FIG. 19 is a diagram illustrating a case where relative coordinates are not applied to the boundaries of objects using the drawing object DO3.

FIG. 20 is a diagram illustrating a data structure of a coordinate string of a drawing object DO3 in which relative coordinates are not applied to a boundary of the object.

FIG. 21 is a diagram for describing relative coordinates applied to a boundary of an object using a drawing object DO3.

FIG. 22 is a diagram illustrating a data structure of a coordinate sequence of a drawing object DO3 in which relative coordinates are applied to a boundary of the object.

FIG. 23 is a diagram for explaining a relationship between a basic character symbol table and a detailed character symbol table.

FIG. 24 is a diagram showing a detailed data structure of a character / symbol table.

FIG. 25 is a diagram for explaining a relationship between first road network data and second road network data.

FIG. 26 is a diagram for explaining the concept of nodes and links.

FIG. 27 is a diagram showing a detailed data structure of a first node table.

FIG. 28 is a diagram showing the arrangement of node records NR1 to NR11 created for nodes N0 to N10 in FIG. 26;

FIG. 29 is a diagram for explaining normalized coordinates, which is one of methods of expressing coordinates of a node in the longitude direction and the latitude direction.

FIG. 30 is a diagram showing a detailed data structure of a first link table.

FIG. 31 is a diagram for explaining link connection information recorded in each link record LR.

FIG. 32 is a diagram for explaining processing when following a connection of a road network based on node connection information and link connection information.

FIG. 33 is a diagram showing a concept of a route search process in the terminal device 1.

FIG. 34 is a flowchart showing a processing procedure of a bidirectional hierarchical search performed by the terminal device 1;

FIG. 35 is a flowchart showing a detailed processing procedure of a map file CF reading process (step S103) of FIG. 34 ;

FIG. 36 is a diagram for explaining a position of a new representative point for determining an adjacent unit NU.

FIG. 37 shows four units U1 to U4 adjacent to each other
It is a figure which shows the road network comprised when lining up.

FIG. 38 is a flowchart showing a processing procedure of the data processing unit 13 when following a connection of a road network across a boundary between two units U.

FIG. 39 is a diagram showing the order in which node records NR of adjacent nodes are recorded.

FIG. 40 is a map file CF of a lower hierarchy and an upper hierarchy
FIG. 9 is a diagram for explaining a problem relating to correspondence between nodes N of FIG.

FIG. 41 is a map file CF of a lower hierarchy and an upper hierarchy
FIG. 7 is a diagram for explaining the correspondence between nodes N.

FIG. 42 is a diagram for explaining a method of searching for a node in the parent unit PU having coordinates corresponding to the node Nd of the child unit CU from the normalized coordinates and the recording order of the node record NR.

FIG. 43 is a diagram for describing processing of the terminal device 1 when a transmission request of the map file CF is requested.

FIG. 44 is a flowchart showing a processing procedure executed by the center station 2 after receiving the request REQ.

FIG. 45 is a diagram showing a structure of each data in a process until a packet P is assembled from a map file CF.

FIG. 46 is a flowchart showing a detailed processing procedure of step S504.

FIG. 47 is a diagram showing a detailed internal data structure of master data MD.

FIG. 48 is a flowchart showing a procedure of a process of receiving a map file CF in the terminal device 1.

FIG. 49 is a flowchart showing the detailed processing procedure of step S703 in FIG. 48.

50. Packets P11, P12,..., P1j,.
FIG. 7 is a diagram showing a structure of each data in a process from the creation of a map file CF to a map file CF.

FIG. 51 is a flowchart showing a detailed processing procedure of step S704 in FIG. 48;

FIG. 52 is a block diagram illustrating a configuration of a map providing system according to a second embodiment of the present invention.

FIG. 53 is a diagram showing the structure of each map file CF stored in the first storage device 1013 shown in FIG.

FIG. 54 is a diagram showing a detailed structure of each unit record UR shown in FIG. 53 (b).

FIG. 55 is a view for explaining the background data BD shown in FIG. 54;

FIG. 56 is a view for explaining the character / symbol data CD shown in FIG. 54;

FIG. 57 is road network data N shown in FIG. 54;
It is a figure for explaining D.

FIG. 58: Basic background table data B shown in FIG. 54
BD, the basic character / symbol data table BCD and the map displayed when the main trunk network data table MND is superimposed, and the detailed background table data DBD and the detailed character / symbol data table D shown in FIG.
It shows a map displayed when a CD and a narrow street network data table SND are superimposed.

FIG. 59 is a flowchart showing a procedure of processing executed in center station 101 shown in FIG. 52.

FIG. 60 shows a structure of each data in a process until the center station 101 shown in FIG. 52 generates a packet P from the map file CF.

FIG. 61 is a flowchart showing a detailed processing procedure included in step S1003 shown in FIG. 59;

FIG. 62 shows a detailed structure of master data MD shown in FIG. 60 (b).

FIG. 63 is a flowchart showing a procedure of processing executed in terminal device 102 shown in FIG. 52.

FIG. 64 is a flowchart showing a detailed processing procedure of step S1203 shown in FIG. 63;

FIG. 65 shows a structure of each data in a process until the terminal device 102 shown in FIG. 52 generates a map file CF from the packet P.

FIG. 66 is a flowchart showing a detailed processing procedure included in step S1204 shown in FIG. 63.

FIG. 67 shows the structure of a map file CF shown in FIG. 52.

FIG. 68 shows a process executed by the file management unit 1025 when the first and second unit IDs do not match in step S1406 shown in FIG.

69 is a basic background data table B shown in FIG. 54.
The BD, the basic character / symbol data table BCD, and the main trunk network data table MND are stored in step S120.
4 shows the structure of the map file CF in a case where the map file CF has already been provided to the terminal device 102 at the time point 4.

FIG. 70 shows a process executed by the file management unit 1025 when the first and second unit IDs match in step S1406 shown in FIG. 66.

FIG. 71 shows a case where a map β representing a certain range is partitioned into 64 rectangular units.

FIG. 72 illustrates a state in which four clusters 91 to 94 having free space have occurred in the storage device of the terminal device.

FIG. 73 shows a case where a map β representing a certain range is partitioned into 16 rectangular units.

FIG. 74 illustrates a case where one cluster 96 having an empty area occurs in the storage device of the terminal device, and further describes that in such a case, the utilization efficiency of the wireless transmission path is reduced. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Terminal device 11 ... Input device 12 ... Position detection device 13 ... Data processing part 14 ... Request generation part 15 ... First transmission / reception part 16 ... Antenna 17 ... Packet disassembly part 18 ... Read / write control part 19 ... First Storage device 110 output device 111 first map file 2 center station 21 second transmission / reception unit 22 reception request analysis unit 23 readout control unit 24 second storage device 25 packet assembly unit 3 communication Network 101 Center station 1011 Map server 1012 Antenna 1013 First storage device 1014 Reading control unit 1015 Packet assembling unit 1016 Transmitting unit 102 Terminal device 1021 Antenna 1022 Receiving unit 1023 Data processing unit 1024 ... Packet decomposing unit 1025 ... File management unit 1026 ... Second storage device

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hisaya Fukuda 1006 Kazuma Kadoma, Kadoma City, Osaka Examiner, Matsushita Electric Industrial Co., Ltd. Makoto Hirai (56) Reference JP-A-7-160982 (JP, A) JP-A-10-255022 (JP, A) JP-A-10-300499 (JP, A) JP-A-10-332398 (JP, A) JP-A-9-307461 (JP, A) JP-A-63-163546 (JP JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06F 17/30 G01C 21/00 G06T 11/60 G08G 1/0969 G09B 29/00

Claims (13)

(57) [Claims] 1. A system in which a center station provides a map file to a terminal device via a transmission line, wherein the center station stores a map file representing a map of a predetermined range; A read control unit that reads a part or all of a map file as map data from the first storage device; and a packet in a format appropriate for the transmission path using the map data read by the read control unit. A packet assembling unit that assembles the packet, and a transmitting unit that transmits the packet assembled by the packet assembling unit to the terminal device through the transmission path, wherein the terminal device is transmitted by the transmitting unit through the transmission path. A receiving unit for receiving the received packet, and decomposing the packet received by the receiving unit to restore the map data. And a second storage device for storing a map file in a storage medium inside the data processing unit, wherein the data processing unit stores the map file related to the map data restored this time in the second storage device. If the map file is already stored in the second storage device, the map file is read from the second storage device, and the restored map data is added to the read map file. A map providing system stored in a storage device. 2. The map providing system according to claim 1, wherein the data processing unit creates a plurality of map files as needed. 3. The map file includes a plurality of units in which the map of the predetermined range is divided into a plurality of areas, and management information for managing each of the units. In the station, the reading control unit executes reading in units of units from a map file stored in the first storage device, and the packet assembling unit reads the unit read by the reading control unit and a map file. File I to be specified
The map providing system according to claim 1, wherein a packet is assembled using D, a unit ID for specifying the unit, and a data size of the unit. 4. The data processing unit further includes a file I based on a packet received by the receiving unit.
4. The map according to claim 3, wherein D, a unit ID, and a data size are extracted, and the packet received by the receiving unit is decomposed to restore map data using the extracted file ID, unit ID, and data size. Delivery system. 5. The map file further includes basic data schematically representing the predetermined range and detailed data representing the range in detail, and the basic data and the detailed data are separable from each other. The map providing system according to claim 1, which has a simple data structure. 6. The basic data further includes basic background data representing a background of the map, basic character / symbol data schematically representing characters and symbols to be displayed on the map, and main trunk lines existing in the map. Main road network data representing a road network of the map, wherein the detailed data further includes detailed background data representing a detailed background of the map, and detailed character / symbol data representing characters and symbols to be displayed on the map in detail. The detailed background data, the detailed character / symbol data, and the narrow street network data include the basic background data, the basic character / symbol data, and the main data. It is configured as difference data of trunk network data, and the basic data and the detailed data By combined, relatively detailed map is expressed, the map providing system as claimed in claim 5. 7. The read control unit according to claim 1, further comprising:
The map providing system according to claim 5, wherein only the basic data included in the map file stored in the storage device is read as map data. 8. The read control unit further includes the first control unit.
The map providing system according to claim 7, wherein only the detailed data included in the map file stored in the storage device is read out as map data. 9. The read control unit according to claim 1, further comprising:
The basic data and the detailed data included in the map file stored in the storage device are read as map data.
The map providing system according to claim 5. 10. The map providing system according to claim 7, wherein said data processing unit further decomposes the packet received by said receiving unit to restore basic data. 11. The read control unit of the center station further reads only detailed data included in a map file stored in the first storage device as map data, and the data processing unit of the terminal device The map providing system according to claim 10, further comprising decomposing the packet received by the receiving unit to restore detailed data. 12. The map providing system according to claim 9, wherein said data processing unit further decomposes the packet received by said receiving unit to restore basic data and detailed data. 13. A terminal device for receiving a map file transmitted by a center station through a transmission line, wherein the center station receives a map file representing a map of a predetermined range from a first storage device that stores a map file. Reading a part or all of the map file as map data, assembling a packet of a format appropriate for the transmission path using the read map data, and transmitting the assembled packet to the transmission path; A receiving unit that receives the packet transmitted by the transmitting unit via the transmission path; a data processing unit that performs processing of decomposing the packet received by the receiving unit and restoring map data And a second storage device for storing a map file in a storage medium therein, wherein the data processing unit stores the map data restored this time. If the map file related to the data is already stored in the second storage device, the map file is read from the second storage device, and further, the restored map data is stored in the read map file. And a terminal device for storing in the second storage device.