JP2000322693A - Mobile communication terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately decide and delete a former file to be unnecessitated by newly acquiring a map data file. SOLUTION: A file (file B) matched with a portion excepting for a numeral part in the file name of a file (file A) newly acquired from an information distribution center is found out of an external memory (S140) and all the files in the area overlapped with the file B among the new files acquired later than the file B are extracted (S160). In the state of synthesizing the area of each of the extracted files and the area of the file A, it is discriminated whether that synthetic area includes all the area of the file B or not (S170). When the synthetic area includes all the area of the file B (S170: YES), the fact shows map data in the area covered by the file B are updated by the map data file acquired later than that file B so that the relevant file B is deleted from the external memory (S180).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication terminal which can be connected to an external information distribution source and can acquire information from the connected information distribution source, such as a communication type car navigation device. And a device having a function of acquiring and updating and storing a map data file.

[0002]

2. Description of the Related Art Conventionally, for example, in a communication type car navigation system, for example, a communication network such as the Internet is connected via a wireless line such as a mobile phone or a car phone, and data requested to be distributed to an information distribution center is obtained ( Download). Considering that it is possible to connect to an information distribution center by connecting a mobile phone, for example, a portable information tool such as a notebook computer or a PDA can also be combined with a mobile phone, etc. Is configured as However, in the following description, the communication type car navigation device will be taken as a representative, and the discussion will proceed.

In the case of a car navigation system, for example, the current position is detected by GPS or the like as the vehicle travels, and the current position is displayed together with a road map on a display to provide guidance (position guidance), A function of setting an appropriate route (destination route) from a vehicle to a destination and performing predetermined guidance (route guidance) so that the vehicle can travel along the destination route is known. These guidance functions are realized using map data stored therein.

Generally, this map data is stored on a CD-ROM.
Or a recording medium such as a DVD, and the recording medium is set in a map data input device and used. That is,
The navigation control device (navigation ECU) inputs map data from the map data input device and executes a predetermined guidance process.

[0005] However, the map data recorded on the recording medium in this manner reflects the situation at the time of recording. For example, after that, a new road is opened or a facility is newly established. In such a case, map data having contents corresponding to those is required. At that time, every time the map data of a part of the area is corrected, it is not efficient to use the data newly stored in the recording medium in the unit of the whole map data, and the economy becomes worse.

For this reason, a communication-type car navigation device that can be connected to an external information distribution source is configured to receive only necessary map data from an information distribution center or the like that provides a map data distribution service. It is also considered to partially update the data with new data. In this case, a method is adopted in which the target map is divided into predetermined regions and the distribution is performed in units of map data files created for each region. Such a distributed map data file is stored, for example, on a hard disk. However, in order to reduce the amount of the file storage medium used by the map data file such as the hard disk, the old map data file corresponding to the newly acquired data is used. It is desirable to delete the data.

[0007]

However, due to the adoption of the technique of acquiring this map data file via a wireless line, there is a restriction on communication and the situation of software for handling the file, so that one area is used. The map data file in units is limited to a certain data size. Therefore, when setting an area for the first time, it is considered that the data size of the map data file in the area unit is equal to or smaller than a predetermined maximum specified size.

However, when a new road is opened or a facility or the like is newly opened after the time when the area is first set, the data size of the map data file of a certain area increases, and the above-mentioned maximum specified size is set. May be exceeded. In that case, the area is divided into two or more areas, and the data size of the map data file in each area is reset so as to be equal to or less than the maximum specified size. Since the area is further divided in this way, the same data cannot be delivered with the same file name as the map data file of the previous area. Therefore, for example, it is assumed that a map data file of one area after division corresponding to a part of a conventional area has the same file name as before, and another file name has been assigned to the remaining area.

In a general file system using a personal computer (hereinafter referred to as a personal computer), when a file is updated, the file is updated only by matching the file name. If the data file is allowed to be updated by matching only the file name, necessary data will be lost. In other words, 1 after division corresponding to a part of the previous area
The map data file of the area is replaced with the map data file of the previous area, and the data of the remaining area is lost without being updated.

[0010] However, in order to avoid such inconvenience,
If the old map data file is not deleted even if a new map data file is acquired, old and new data will be mixed in the same area, and the amount of file storage medium capacity such as a hard disk used by the map data file will increase. Would. In particular, mobile communication terminals such as communication-type car navigation devices are required to have as little extra data as possible from the viewpoint of preventing the file storage medium from becoming larger due to an increase in the capacity of the file storage medium.

Accordingly, the present invention provides a method for appropriately determining and deleting an old file which is no longer necessary due to the acquisition of a new map data file, so that only the necessary map data file can be left in the file storage means. It is intended to provide a communication terminal.

[0012]

According to a first aspect of the present invention, there is provided a mobile communication terminal, wherein a target map is divided into a plurality of predetermined regions when the target map is divided into predetermined regions. The created map data file can be stored in the file storage means, and the information providing means
Using the map data file stored in the file storage means, predetermined information is provided.

[0013] Then, it is possible to connect to an external information distribution source via a wireless line and obtain a map data file from the connected information distribution source. If you do this,
When the contents of the map data file are changed in a certain area, for example, when a new road is opened, a new map data file matching the changed contents can be obtained. If the acquired map data file is stored in the file storage means by the storage control means, thereafter, the above-mentioned information provision can be executed for the corresponding area by using the changed map data file.

However, if only the new map data file is stored in this way and the old data is left as it is, new and old data are mixed in the same area, and the map data file is not stored in the file storage means. Occupies an increased amount of use. In particular, in a mobile communication terminal such as a communication type car navigation device, an increase in the capacity of the file storage means leads to an increase in the size of the file storage means.

Therefore, the storage control means of the present invention appropriately determines and deletes an old file which is no longer necessary when a new map data file is obtained, thereby leaving only the necessary map data file in the file storage means. Like that. In such a determination, an area on the map corresponding to the map data file is divided and / or divided according to at least one of a change in the data amount of the map data file and a section change performed from the viewpoint of map management. It is assumed that they will be integrated. In other words, if the area of the map data file initially set does not change at all, the area of the new data and the area of the old data completely match, so the old data is deleted and the new data is stored.
What is called “update” storage may be performed. However, in practice, as described above, a new road is opened or a facility or the like is newly constructed, so that the data size of the map data file in a certain area increases and exceeds the maximum specified size, When a new map data file is distributed, the previous area is divided into two or more areas. Also, even if the data amount itself does not change, for example, if the division is made in the administrative area for map management, if the division is changed due to the consolidation of the administrative area, the division and integration of the area will be similarly performed. Will be done. Of course, the data may be divided / integrated in accordance with both the change in the data amount and the change in the partition described above, or may be based on other circumstances.

Therefore, when the "update only by matching file names" method in a general file system using a personal computer or the like is employed, although the conventional map data file is partially required,
Deleting the conventional map data file results in the loss of necessary data.

Therefore, the present invention employs the following method. In other words, of the “deletion candidate areas” that are areas on the map corresponding to the conventional map data file, when considered in map data file units, the “deletion candidate areas” that are areas on the map corresponding to the acquired map data file. Judgment area "
"Area comparison determination" is performed to determine whether or not there is any one included in the. Then, when it is determined by the area comparison determination that there is a deletion candidate area included in the deletion determination area, the corresponding conventional map data file is deleted from the file storage unit. In this case, even if the file names match, area comparison determination is performed.

In this way, if a newly obtained map data file is used, the (previous) map data file of the corresponding area can be deleted only when the previous data need not be used at all. Therefore, only the necessary map data file can be left in the file storage means, and a relatively small capacity file storage means can be used.

By the way, specifically, there are the following two modes when the area covered by the newly acquired map data file is different from the area covered by the previous map data file. (A) The case where the area covered by the newly acquired map data file overlaps only part of the area covered by the previous map data file. This may be the case, for example, when the data capacity is increased due to a new road being opened and the area is divided into two or more.

(B) When the area covered by the newly acquired map data file overlaps with all the areas covered by the previous map data file. This is contrary to (A), as a result of depopulation and the construction of large-scale factories,
It is conceivable that the existing roads and facilities have disappeared.

Considering the existence of these two types of modes, the storage control as described in claim 2 is preferable. That is, first, an area comparison determination is performed using the deletion determination area of only the acquired latest map data file and the deletion candidate area. Then, when there is a deletion candidate area including the entirety in the deletion determination area, the corresponding conventional map data file is deleted from the file storage means. This corresponds to the above-described mode (B) or the mode in which the area itself is not changed by the new and old map data files.

On the other hand, as a result of the area comparison judgment, when there is a deletion candidate area including only a part thereof in the deletion judgment area, that is, in the case of the above-described mode (A), the following storage control is performed. Do. First, the deletion determination area of the map data file obtained from the time when the previous map data file corresponding to the deletion candidate area is stored in the file storage means until the latest map data file is obtained is stored in the latest map data file. A combination with the deletion determination area is set as a new deletion determination area, and an area comparison determination is performed. Then, when there is a deletion candidate area included in the combined new deletion determination area, the corresponding previous map data file is deleted from the file storage unit.

When the previous area is divided into two or more, the previous area cannot be covered by only a part of the divided area, and the previous map data file cannot be deleted as it is. However, for example, the previous area is 2
In the case of division, if a new map data file corresponding to each of the two divided areas is obtained, the previous map data file may be deleted. According to the above-described method, such a situation can be appropriately determined.

It is to be noted that a map obtained by combining the deletion determination area of the acquired map data file with the latest deletion determination area between the time when the previous map data file is stored and the time when the latest map data file is obtained is newly added. However, if no restriction is imposed, it is necessary to handle even a deletion determination area that is completely unrelated to the deletion candidate area. Therefore, claim 3
As shown in the above, in the map data file acquired from the time when the previous map data file was stored to the time when the latest map data file was acquired, an area including at least a part of the deletion candidate area in the deletion determination area is determined. May be combined with the deletion determination area of the latest map data file.

When at least a map is displayed as information provision by the information provision means, a map data file obtained from the outside includes:
The information providing means includes data used for map display. When a predetermined guidance based on a map is executed, a map data file acquired from the outside includes data used when the predetermined guidance is executed. As this predetermined guidance, as shown in claim 6,
At least route guidance to the destination is included. Also,
It may be a guide that displays the location of a facility such as a nearby gas station, convenience store, or parking lot.

These are all functions that are currently realized in general car navigation systems. Therefore, as described in claim 7, the mobile communication terminal according to any one of claims 4 to 6 can be realized as a communication-type navigation device mounted on a vehicle. In that case, for example, an existing mobile phone or car phone can be used as the communication means.
Of course, a navigation device incorporating this communication function may be used. Further, instead of such a communication type navigation device, a mobile communication terminal carried by a person may be used. A portable information tool such as a notebook personal computer or a PDA having a built-in communication function can also be adopted as the mobile communication terminal in the present invention.

When the map data file is obtained by the file obtaining means, for example, a request for transmission of the map data file to an external information distribution source side using a communication means is made as described in claim 8, and as a result, It is conceivable to obtain a map data file transmitted from the information distribution source. In other words, the mobile communication terminal is mainly responsible for requesting transmission of a necessary map data file. Such a method is preferable because the contents of the necessary map data file differ depending on the circumstances of each mobile communication terminal.

When connecting to the information distribution source by the communication means, the Internet may be used, but the present invention is not limited to this.
An ICS system, an information service network for car navigation (for example, “MONET”) or the like may be used.

The function of realizing the storage control means in the mobile communication terminal in a computer system is as follows.
For example, it can be provided as a program started on the computer system side. In the case of such a program, for example, a floppy disk, a magneto-optical disk,
It can be used by recording it on a computer-readable recording medium such as a D-ROM or a hard disk, loading it into a computer system as needed, and starting up. Alternatively, the program may be recorded in a ROM or a backup RAM as a computer-readable recording medium, and the ROM or the backup RAM may be incorporated in a computer system and used.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. It is needless to say that the embodiments of the present invention are not limited to the following examples, and can take various forms as long as they belong to the technical scope of the present invention.

In this embodiment, since the mobile communication terminal is applied to a navigation device, a schematic configuration of the navigation device 1 will be described with reference to FIG. The navigation device 1 of the present embodiment is configured as a communication type navigation device mounted on a vehicle, and includes a position detector 12 for detecting a current position of the vehicle and a wireless telephone line for collecting various road traffic information. A communication device 18 for performing data communication with the information distribution center 4 via an external device, an external information input / output device 19, an operation switch group 20 for inputting various commands to the device, and the same as the operation switch group 20 Remote control sensor 21 for inputting a signal from a remote control terminal (hereinafter, referred to as a remote controller) (not shown) capable of inputting various kinds of commands, a map data input device 22, an external memory 24, and a display screen on an instrument panel (instrument panel). Is embedded,
A display device 26 for performing various displays such as a map display screen and a TV screen in addition to a display such as a speedometer and a tachometer.
And various processes are executed in response to inputs from the position detector 12, the operation switch group 20, the data input device 22, and a remote controller (not shown), and the communication device 18, the external information input / output device 1
9, an external memory 24, and a navigation control circuit 30 for controlling the display device 26.

Here, the position detector 12 is a GPS (Glob)
al Positioning System) receives the transmitted radio wave from the satellite via the GPS antenna,
A GPS receiver 12a for detecting speed and the like, and a gyroscope 12 for detecting the magnitude of a rotational motion applied to the vehicle
b, a vehicle speed sensor 12c comprising a vehicle speed sensor, a wheel sensor, and the like, for detecting the traveling distance of the vehicle, and a geomagnetic sensor 12d for detecting an absolute bearing based on geomagnetism. And each of these sensors 12a to 12d
Are configured to be used while complementing each other because each has an error having a different property. Depending on the accuracy, only a part of the above-described sensors 12a to 12d may be used. Alternatively, the steering angle of the vehicle obtained from the rotation difference between the left and right steering wheels may be accumulated to change the direction. A sensor or the like to be obtained may be used.

The communication device 18 is determined via a wireless telephone device 18a such as a portable telephone or a car telephone which can be connected to a public telephone network and a wireless telephone device 18a in accordance with a command from the navigation control circuit 30. Connection with an information distribution center, which is an external information source, and encodes data from the navigation control circuit 30 into a form that can be transmitted via the wireless telephone device 18a, and inputs the data via the wireless telephone device 18a. And a modem 18b for decoding the received data into a form that can be processed by the control circuit 30.

On the other hand, the external information input / output device 19 receives an FM broadcast signal via a radio antenna (not shown), or receives a VICS (Vehicle Information) disposed near a road.
ion and Communication System) Receives a radio beacon signal and an optical beacon signal from a fixed station for service. The received information is sent to the navigation control circuit 30 for processing. In addition, information can be transmitted to the outside.

Next, as the operation switch group 20, a touch switch integrally formed with the display device 26 and set on a display screen or a mechanical key switch provided around the display device 26 is used. Next, the map data input device 22 is used to input from a storage medium various data including so-called map matching data for improving the accuracy of position detection, road data representing road connections, and facility data described below. Device. As a storage medium, a CD-ROM is generally used because of its data amount, but another medium such as a DVD or a memory card may be used. The road data forms a map by connecting a plurality of nodes such as intersections with links, and for each link, a unique number (link ID) for specifying the link and a link indicating the length of the link It stores link information including data on length, x and y coordinates of the start and end of the link, road width of the link, and road type (indicating road information such as toll roads).

On the other hand, as the external memory 24, a nonvolatile memory is used for storing a map data file as described later. In consideration of the data capacity of the map data file, it is preferable to use, for example, a hard disk. The display device 26 is a color display device, and displays on its screen a mark indicating the current position of the vehicle detected by the position detector 12, road data input from the map data input device 22, and further on a map. It is possible to superimpose and display additional data such as a guide route, a name and a mark.

Next, the navigation control circuit 30 includes a CPU, RO
It is mainly composed of a well-known microcomputer composed of M and RAM, and has a current position of the vehicle based on each detection signal from the position detector 12 and a map near the current position read through the map data input device 22. On the display screen, a destination selection process for selecting a destination facility in accordance with operation of the operation switches 20 and the remote controller based on the facility index data stored in the map data input device 22, and a current position. A so-called navigation process such as a route guidance process for automatically selecting an optimal route from a destination to a destination and performing guidance in accordance with the selected route is executed. As a technique for automatically setting the optimum route, a technique such as the Dijkstra method is known.

Further, it is also possible to provide guidance for displaying the locations of facilities such as a nearby gas station, convenience store, or parking lot. Further, the navigation control circuit 30 can execute a predetermined process to make a request for information distribution to the external information distribution center 4 via the communication device 18. , And stores it in the external memory 24. Information distributed from the information distribution center 4 includes an application program and a map data file. The map data file is used as follows.

That is, in the navigation device 1, various navigation processes are executed based on the map data as described above. For example, a storage medium (for example, a CD) for reading data through the map data input device 22
-ROM or DVD), a map covering the whole country may be prepared, or only a map of a frequently used area may be prepared. Then, other map data is downloaded from the information distribution center 4 when needed. Since the map data itself may be updated, the updated map data may be downloaded in the same manner. These downloaded map data files are stored in the external memory 24. Of course, if the map data file once stored in the external memory 24 no longer matches the actual situation, a new map data file is acquired and stored in the external memory 24.

As described above, since the map data file updated in units of areas is stored in the external memory 24,
The navigation control circuit 30 executes the above-described navigation processing using not only the map data input via the map data input device 22 but also the map data stored in the external memory 24.

Here, the map data file will be described. In the present embodiment, a map data file is a file in which data of each area unit obtained by dividing a target map area into rectangles is used as a map data file, and one area divided by vertical and horizontal lines shown in FIG. Applicable to map data files. In addition, in FIG. 2 (a), a very coarse vertical and horizontal line is shown using a map of Japan as an example for conceptual illustration.
In many cases, a map of a plurality of scales is divided into regions to generate respective map data files. For example, an area of several tens of kilometers square, several kilometers square, and several hundred meters square. Therefore, a plurality of map data files correspond to the same point.

In the present embodiment, the target map area is divided into rectangles, but need not necessarily be divided into rectangles. Of course, it is preferable to divide into rectangles from the viewpoint of data processing, but from another point of view, it may not be preferable to divide into rectangles uniformly.
For example, in the case of partitioning by administrative boundaries in map management, the shape of the partition in the administrative boundary is the shape of the area.

Next, the structure of the name of the map data file will be described. The map data file, as shown below,
It consists of an alphabet part, a number part and an extension. The alphabet part indicates the name of the representative city included in the map of the corresponding area, and the numeral part indicates the number of the divided area. An extension (map) indicates a map data file.

On the other hand, as shown in FIG. 2B, the data structure of the map data file includes a management unit and a map data unit. In the management unit, the file type is a map file, and two points for specifying a covering rectangular map area, that is, coordinate data of longitude and latitude of two points, upper left and lower right, are stored. . The map data section stores map data and the like.

The configuration of a general map data file has been described so far. Here, a situation in which an area is divided will be described. For example, FIG. 3A shows a map data file for a certain year (denoted as X year), and FIG. 3B shows a map data file for the next year, X + 1. The data amount of one file is considered to be equal to or less than the maximum specified size.

Here, the maximum specified size will be described. The map data file is distributed from the information distribution center 4 to the navigation device 1 via a wireless line.
Due to this point, the map data file in one area unit is limited to a certain data size due to communication restrictions and software circumstances in the navigation device 1 that handles the file. Therefore, when setting an area for each file, the data size of the map data file in area units is set to be less than or equal to the maximum specified size. The maximum specified size may be determined in consideration of another viewpoint. That is, the map data file is distributed from the information distribution center 4 to the navigation device 1. In this distribution, the data size can be a unit of billing. In this case, even if the number of updated portions is small, distribution can be performed only in map data file units, so if the data size is large, the fee burden will be excessive. Therefore, the data size may be set to be smaller than the data size determined from the above-described communication restrictions and the situation of software in the navigation device 1 that handles files.

For example, in FIG. 3A, a representative city name n
"na" that stores the first map data of the area of agoya
goya1. Attention is paid to “map”. Although the amount of data that could be stored in one file in year X was increased by the number of roads and houses in this area by year X + 1, the data amount exceeded the maximum specified size of one file and was 1. Suppose that it has increased five times. As described above, inconvenience occurs when the data amount of one file exceeds the maximum specified size, so that the first map data in the area having the representative city name nagoya has to be divided. In this case, the area is divided into two so that the data amount of each area is equal to or less than the maximum specified size. This is performed on the information distribution center 4 side, and if there is a request from the navigation device 1,
The two divided map data files will be distributed.

In this embodiment, file names are given to the two divided map data files as follows. First, as for the alphabet part, "nagoya" which is the representative city name included in the map is not changed and is used as it is. As for the numeral part, the area to be covered changes, so it is necessary to change it. Here, since the inside of the first area in the related art is divided into two, “11” and “1”
2 ". As a result, the file names of the two map data files after division are “nagoya11.map” and “nagoya”, as shown in FIG.
ya12. map ".

Therefore, in the navigation device 1 which acquired the map data file shown in FIG. 3A from the information distribution center 4 in year X, when the year X + 1 is reached,
The file content of “nagoya1.map” shown in (a) does not match the current state. Therefore, when the navigation apparatus 1 reaches X + 1 year, the navigation apparatus 1 selects “na” shown in FIG.
goya11. map "and" nagoya12.ma
By obtaining “p” from the information distribution center 4 again, this change can be dealt with. "Nagoya" obtained in this way
11. The "map" and "nagoya12.map" are stored in the external memory 24. However, if only the new map data file is stored and the old data is left as it is, new and old data are mixed in the same area, and the external memory 24 The use amount occupied by the map data file is increased with respect to the storage capacity in 24. Therefore, it is demanded that extra data is not stored as much as possible.

Therefore, in the navigation device 1 of the present embodiment, an old file which becomes unnecessary when a new map data file is acquired is appropriately determined and deleted, so that the necessary map data file is stored in the external memory 24. Only to leave. About the processing contents at that time,
This will be described with reference to the flowchart of FIG.

The process shown in FIG.
0, etc., to input an instruction to update the map data file to the navigation device 1, and assume that the navigation device 1 has requested the information distribution center 4 to distribute the corresponding map data file based on the instruction. I do. Note that the navigation device 1 automatically distributes information when the current map detected with the movement of the vehicle moves and the necessary map disappears at that time, not based on the update instruction from the user. A distribution request may be made to the center 4.

Further, on the contrary, a system in which the information distribution center 4 inquires of the navigation apparatus 1 about the necessity of updating may be used. Further, when a distribution request is made to the information distribution center, for example, it is conceivable to notify the target area and the time when the apparatus has finally received the distribution of the map data file. In this way, the information distribution center 4 selects only the map data file that has been updated later in the corresponding area (that is, since the time when the navigation device 1 last received the distribution of the map data file). Then, it can be distributed to the navigation device 1 side.

In the first step S110 in FIG. 4, the reception of the map data file distributed from the information distribution center 4 is waited, and the reception is completed (S120: YE
S), the navigation control circuit 30 stores the received map data file (hereinafter referred to as the map data file received from the information distribution center 4 in the current process in the file A).
Called. ) Is renamed, transferred to the external memory 24, and stored (S130). The name is changed here because the file name may be duplicated with the already received file name. However, the alphabet part indicating the representative city name shall not be changed.

In S140, the external memory 24 searches the external memory 24 for a file that matches the portion of the file name of the received file A except for the numeral portion (such a file is referred to as file B). That is, it is a file in which the alphabet part matches the extension map.

If such a file B is not found (S150: NO), the process is terminated as it is. If a corresponding file B is found (S150: YES), the process proceeds to S160. Transition. S16
0 indicates the area covered by the file B in FIG.
In the external memory 24, all files having an area overlapping with the file B are extracted from the new files acquired after the file B in the external memory 24. Then, an area is extracted from the management unit of each extracted file, and in a state where the areas are combined, it is determined whether or not the combined area includes all the areas of the file B (S17).
0). This is the case when the combined area matches the area of file B or the combined area is larger than the area of file B. Of course, not only the size of the area is a problem, but it is necessary that the entire area of the file B be included in the combined area.

If the combined area includes all the areas of file B (S170: YES), the map data file newly acquired from file B
Since the map data of the area covered by is updated, the file B is deleted from the external memory 24 (S180). Thereafter, the process returns to S140. And
If any of the received files A has not been processed yet, the process from S140 on is performed for the file A.

On the other hand, if the area obtained by combining the areas of the extracted file does not include the entire area of the file B (S170: NO), the file B is transferred to the next S.
After being excluded from the search target in 140 (S190), S1
Return to 40. In this embodiment, the external memory 2
Reference numeral 4 corresponds to a file storage unit, and the navigation control circuit 30 and the display device 26 correspond to an information providing unit. The communication device 18 corresponds to a communication unit, and the navigation control circuit 30 corresponds to a file acquisition unit and a storage control unit. And FIG.
The execution of the processing of S110 and S120 corresponds to the execution of the processing as the file acquisition means, and the execution of the processing of S130 to S180 corresponds to the execution of the processing as the storage control means.

As described above, according to the navigation device 1 of the present embodiment, the map data file is
Can be acquired and stored in the external memory 24,
The navigation control circuit 30 performs predetermined navigation processing such as map display and route guidance using the map data file stored in the external memory 24. When the contents of the map data file are changed in a certain area, for example, when a new road is opened, a new map data file matching the changed contents is obtained from the information distribution center 4. it can. However, if the new map data file is merely stored in this way and the old data is left as it is, new and old data are mixed in the same area, and the map data file occupies the storage capacity of the external memory 24. The usage increases. In particular, in the case of the in-vehicle navigation device 1,
An increase in the capacity of the external memory 24 leads to an increase in the size of the external memory 24. Therefore, it is desired that the external memory 24 has as little extra data as possible.

Therefore, in the present embodiment, an old file which becomes unnecessary when a new map data file is obtained is appropriately determined and deleted, so that only the necessary map data file is left in the external memory 24. did. At this time, if the area of the map data file initially set does not change at all, the area of the new data and the area of the old data completely match, so the "update" processing of simply deleting the old data and storing the new data Should be performed. However, in practice, as described above, a new road is opened or a facility or the like is newly constructed, so that the data size of the map data file in a certain area increases and exceeds the maximum specified size, When a new map data file is distributed, the previous area may be divided into two or more areas.

Therefore, in this embodiment, as shown in S160 of FIG. 4 described above, a file B having an area overlapping with the acquired file A is found, and the file B
From among the new files acquired later than this, all the files overlapping the area of the file B are extracted, and the extracted file and the area of the file A are combined. Then, the file B is deleted from the external memory 24 only when the combined area includes all the areas of the file B.

In this way, if a newly obtained map data file is used, the (previous) map data file of the corresponding area can be deleted only when the previous data need not be used at all. Therefore, only the necessary map data file can be left in the external memory 24, so that the external memory 24 having a relatively small capacity can be used.

[Others] (1) In the above-described embodiment, as shown in S160 of FIG. 4, a file having an area overlapping with the file B is extracted from among the files acquired after the file B and newly added. After combining the acquired areas of the file A, the area determination in S170 is performed. However, there are two types of modes when the area covered by the acquired map data file is different from the area covered by the conventional map data file.

(A) When the area covered by the newly acquired map data file overlaps only part of the area covered by the previous map data file. This may be the case, for example, when the data capacity is increased due to a new road being opened and the area is divided into two or more.

(B) A case where the area covered by the newly acquired map data file overlaps with all the areas covered by the previous map data file. This is contrary to (1), as a result of depopulation and the construction of large-scale factories,
It is conceivable that the existing roads and facilities have disappeared.

The method of the above-described embodiment is, of course, effective for any of these two modes.
If attention is paid to the existence of the mode (B), the following method may be adopted. That is, first, an area comparison determination is performed using only the area of the file A and the area of the file B.
In the case of the mode (B), in this determination, the area of the file A includes the entire area of the file B.
Therefore, the file B can be deleted only by this determination.
Then, in the case of the mode (A), the file B cannot be deleted only by this area determination, so that processing such as S160 and S170 in FIG.

(2) In the above-described embodiment, the file B having an area overlapping with the file A is extracted with reference to the alphabet part indicating the representative city name, or the file having the area overlapping with the file B is extracted. Extracted. On the other hand, when the file name does not have a meaning such as a place name and the file name itself is given a name indicating an area, FIG.
In S140, all files are targeted. In S160, an area overlapping with the file B is searched for by combining and comparing areas based on the file name itself, not on the management information.

Further, if the file name has no meaning such as area and place name, the file B is searched for all files in S140 of FIG. (3) In the above-described embodiment, an example in which the present invention is applied to the navigation device 1 has been described. However, the present invention can be applied to a mobile communication terminal carried by a human. It is a portable information tool such as a notebook personal computer or a PDA with a built-in communication function.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a schematic configuration of a navigation device according to an embodiment.

FIG. 2 is an explanatory diagram of a map data file.

FIG. 3 is an explanatory diagram showing an example of updating a map data file.

FIG. 4 is a flowchart showing a process of receiving and updating a map data file in the navigation device.

[Explanation of symbols]

Reference Signs List 1 navigation device 4 information distribution center 12 position detector 12a GPS receiver 12b gyroscope 12c vehicle speed sensor 12d geomagnetic sensor 18 communication device 18a wireless telephone device 18b modem 19 external information input / output device Reference Signs List 20 operation switch group 21 remote control sensor 22 map data input device 24 external memory 26 display device 30 navigation control circuit

Claims (8)

[Claims] 1. A file storage means for storing a map data file created for each area when a target map is divided into predetermined areas, and map data stored in the file storage means. Information providing means for providing predetermined information using a file; communication means for connecting to an external information distribution source via a wireless line; and the map data file from the information distribution source connected by the communication means. A mobile communication terminal comprising: a file acquisition unit that acquires the map data file; and a storage control unit that stores the map data file acquired by the file acquisition unit in the file storage unit. The upper area responds to at least one of a change in the data amount of the map data file and a section change performed from the viewpoint of map management. Assuming that the map is divided and integrated, the storage control means, when considered on a map data file basis, among the deletion candidate areas that are areas on the map corresponding to the conventional map data file, An area comparison determination is performed to determine whether or not there is any included in the deletion determination area that is an area on the map corresponding to the data file. If the deletion candidate area included in the deletion determination area exists, A mobile communication terminal, wherein the corresponding conventional map data file is deleted from the file storage means. 2. The mobile communication terminal according to claim 1, wherein the storage control unit first performs the area comparison determination based on the deletion determination area of only the acquired latest map data file and the deletion candidate area. If the deletion candidate area including the entirety of the deletion candidate area exists in the deletion determination area, the corresponding previous map data file is deleted from the file storage unit. On the other hand, as a result of the area comparison determination, the deletion is performed. In the case where the deletion candidate area including only a part thereof is included in the determination area, the latest map data from the time when the previous map data file corresponding to the deletion candidate area is stored in the file storage means. The deletion determination area of the map data file acquired until the file is obtained is combined with the deletion determination area of the latest map data file. The combined area is set as a new deletion determination area, the area comparison determination is performed, and if the deletion candidate area included in the combined new deletion determination area exists, the corresponding previous map data A mobile communication terminal, wherein a file is deleted from the file storage means. 3. The mobile communication terminal according to claim 2, wherein the storage control means stores the previous map data file corresponding to the deletion candidate area when setting the new deletion determination area. In the map data files acquired from the time of storing the latest map data file to the time of acquiring the latest map data file, only those having the area including at least a part of the deletion candidate area as the deletion determination area, A mobile communication terminal, which is combined with a deletion determination area of a latest map data file. 4. The mobile communication terminal according to claim 1, wherein the information providing means is capable of at least displaying a map, and the map data file acquired from the outside includes the information providing means. Wherein the mobile communication terminal includes data used for map display. 5. The mobile communication terminal according to claim 1, wherein the information providing means is capable of executing a predetermined guidance based on a map, and the map data file acquired from the outside includes: A mobile communication terminal including data used when the information providing unit executes the predetermined guidance. 6. The mobile communication terminal according to claim 5, wherein said predetermined guidance is at least route guidance to a destination. 7. The mobile communication terminal according to claim 4, wherein the mobile communication terminal is realized as a communication-type navigation device mounted on a vehicle. 8. The mobile communication terminal according to claim 1, wherein the file acquisition unit requests the external information distribution source to transmit the map data file using the communication unit. A mobile communication terminal for acquiring the map data file transmitted from the information distribution source as a result.