JP2004101982A - Map data download method and communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently download map data from a server to a communication terminal while properly securing memory free capacity of the communication terminal and coping with updating of map data at the server side. <P>SOLUTION: The server 13 divides a map 11 by a geographical block unit and stores it together with the information of size and update history as a map data table 12. The communication terminal 14 downloads the map data by the block unit. At this time, the communication terminal 14 selects and downloads only the map data with new updating history when the map data are that of already stored block, and deletes unnecessary map data and others in advance when the memory free capacity is not enough. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a map data download method and a communication terminal, and more particularly to a download method when map data is downloaded from a server to a communication terminal and used, and a communication terminal used therefor.
[0002]
[Prior art]
Downloading map data from a server to a communication terminal is widely performed as one of the familiar forms of Internet use, but since map data is a type of image data, it has a relatively large capacity and requires a long download time. Tend to require. In addition, it is often necessary to download map data of a certain geographical area once and immediately display it on the screen, and then download map data adjacent to the downloaded map data and display it on the screen. There are some characteristics unique to data. Therefore, it is desired to shorten the download time and improve the convenience by devising the once downloaded map data in the communication terminal so that it can be reused immediately. However, since the memory storage capacity of a communication terminal is generally limited, it is often necessary to consider securing free space.
[0003]
As an example, the invention disclosed in Patent Document 1 aims to realize such an improvement in convenience in a navigation system while taking into consideration securing a free space of a memory (a hard disk or the like) of a main body. In this navigation system, prior to transferring map data from an external storage medium (such as a DVD-ROM) to the memory of the main body, data that is determined to be unnecessary based on predetermined conditions is deleted from the memory of the main body and the required data is deleted. Free up space. In addition, as the predetermined condition, the distance from the own vehicle position, the number of accesses, or the elapsed time since the last access is exemplified.
[0004]
[Patent Document 1]
JP 2001-165669 A
[Problems to be solved by the invention]
The above-mentioned conventional technology can be applied to the Internet environment by replacing the external storage medium with a server and the memory of the main body with a communication terminal. No response has been taken into account. That is, in the metropolitan area, buildings, shops, transportation infrastructure, and the like are frequently changed, and therefore, map data needs to be updated on a daily basis. Also, in the Internet environment, when the map data on the server side is updated, it can be downloaded to the communication terminal each time and can be used promptly, so that a method for utilizing this feature will be considered separately. There is a need.
[0006]
Accordingly, the present invention provides a method of downloading map data from a server to a communication terminal, which can efficiently perform the download of map data while appropriately securing the memory free space of the communication terminal and supporting the update of map data on the server side. It is an object to provide a method and a communication terminal.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a map data download method according to the present invention includes a server that stores map data in block units, and a memory that stores a part of the map data, and downloads the map data to the server. A map data download method for a system having a communication terminal requesting map data, wherein the server updates the map data in block units according to a map change, and adds and stores information of the update history. The communication terminal, when downloading the block-based map data from the server, receives the update history information corresponding to the block requested to be downloaded from the server, and stores the update history information stored in the communication terminal. Comparing the update history information with the received update history information, and as a result, the stored update history If the information matches the information, the stored map data is used for display without downloading, and if the information does not match the information of the stored update history, the map data of the block is downloaded from the server and used for display. It is characterized by the following.
[0008]
According to the present invention, accurate and efficient map display can be performed in the communication terminal by downloading only the map data that is truly needed.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
(First Embodiment)
Hereinafter, a first embodiment of a map data download method and a communication terminal according to the present invention will be described with reference to FIGS. FIG. 1 is a conceptual diagram of transmission and reception of map data between a server and a communication terminal according to the first embodiment of the present invention.
[0010]
In the figure, 11 is a map. The whole map is divided into a matrix of m × n (m and n are integers), and each divided geographic block is marked with a symbol. In FIG. 1, 9 blocks of 3 × 3 are represented by symbols Aa, Ab,..., Cc.
[0011]
Reference numeral 12 denotes map data obtained by converting the map 11 into a database in a table format. The “block symbols” in the figure represent symbols Aa, Ab,..., Cc assigned to individual geographic blocks on the map 11. The "update history" displays the update history of the map data for each geographical block, and the number represents the number of updates. In this case, for example, the update count of the block “Ab” is 0, the update count of “Ac” is 2, and the update count of “Ba” is 1. This table further includes information on the size of the map data in block units and the map data itself.
[0012]
Reference numeral 13 denotes a server, and 14 denotes a communication terminal. The table-format map data 12 is stored in a disk storage device or the like of the server 13, and when updating is necessary, the server 13 updates the "map data" and "update history" of the map data 12 in block units. And also updates the "size" information as needed. The communication terminal 14 specifies the block number of the required map data, accesses the map data 12 stored by the server 13, and downloads the updated location history, size, and the contents of the map data in specified block units.
[0013]
FIG. 2 is a block diagram showing a detailed configuration of the communication terminal 14. In this case, a wireless communication terminal is assumed. In the figure, 201 is an antenna, 202 is a transmission / reception switching unit, 203 is a reception unit, 204 is a transmission unit, 205 is a modulation / demodulation unit, 206 is a DA conversion unit and driver, 207 is a voice-electric conversion unit and AD conversion unit, and 208 is A receiver, 209 is a transmitter, 213 is a battery, and 214 is a power supply unit. These are generally included in the configuration of the wireless communication terminal.
[0014]
Reference numeral 210 denotes a control unit, 211 denotes a ROM, 212 denotes a RAM, 215 denotes a display unit, and 216 denotes an operation input unit. These are also generally included in the configuration of the wireless communication terminal. Regarding the use of the two types of memories, the ROM 211 stores basic programs and basic setting data commonly used regardless of the type of application, and the RAM 212 stores various application programs and necessary data, and stores data. It is used for various uses such as buffering and expansion of the work area of the control unit 210. The map data downloaded from the server is stored in the RAM 212.
[0015]
FIG. 5 shows an example of the storage capacity allocation of the RAM 212. In this figure, dark portions indicate various application programs and necessary data described above, buffering of data, expansion of a work area of the control unit 210, and an area allocated to map data. Indicates the free space.
[0016]
Both the ROM 211 and the RAM 212 may be configured using a non-volatile memory, or may be configured to function as a non-volatile memory by being constantly supplied with power from the battery 213 or the power supply unit 214 using a volatile memory. You may.
[0017]
Next, an operation of the communication terminal according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a flowchart showing the operation according to the first embodiment of the present invention, and FIG. 4 is a diagram showing the update history of the map data newly downloaded from the server and the update history of the map data held so far. It is a figure which shows the comparison of.
[0018]
First, a map display area is specified in the operation input unit 216 (step S301 in FIG. 3). In this case, an area consisting of nine blocks of “Aa” to “Cc” shown in FIG. 1 is designated, and the RAM 212 stores map data of six blocks of “Aa” to “Bc” in the RAM 212. The following description will be made on the assumption that the data is stored by downloading (FIG. 4).
[0019]
Upon receiving the designation of the map display area, the control unit 210 first downloads the “update history” and “size” information of the designated block map data “Aa” to “Cc” to the server 13. Request. In this case, the download request output from the control unit 210 is transmitted through the modem unit 205, the transmission unit 204, the transmission / reception switching unit 202, and the antenna 201, and the components of the intervening network (the base station and the mobile phone). It corresponds to a terrestrial network component (not shown in FIG. 1), and reaches the server 13.
[0020]
When the server 13 returns the “update history” and “size” information of each of the “Aa” to “Cc” blocks shown in FIG. 1 in response to the download request, the information is transmitted through the reverse route. Through the antenna 201, the transmission / reception switching unit 202, the reception unit 203, and the modulation / demodulation unit 205, and are input to the control unit 210 and temporarily stored in the buffering area of the RAM 212 (step S302). .
[0021]
Next, the control unit 210 searches the map data of each of the blocks “Aa” to “Cc” specified this time from the map data in units of blocks stored in the RAM 212 by the previous download (step S303). ). In this case, as a result of the search, it is found that the map data of each of the blocks “Aa” to “Bc” has already been stored in the RAM 212 and the map data of each of the blocks “Ca” to “Cc” does not exist in the RAM 212 (step S304).
[0022]
The control unit 210 then stores the update history of the map data of each of the existing blocks “Aa” to “Bc” in the RAM 212 (“existing block” in step S303) in the newly downloaded buffering area of the RAM 212. A comparison is made with the latest update history temporarily stored (step S305). In this case, FIG. 4 shows that only the update histories of the block “Ab” do not match, and the update histories of the other blocks match. As a result, the control unit 210 recognizes that the map data must be newly downloaded for the block “Ab” (“unmatched block” in step S305).
[0023]
Therefore, the control unit 210 reads out the size information of the map data of each of the blocks “Ca” to “Cc” in which the map data does not exist in the RAM 212 and the block “Ab” whose update histories do not match from the buffering area of the RAM 212. On the other hand, the free capacity of the RAM 212 is confirmed by the hardware resource management function generally provided as the control unit 210 of the communication terminal (step S307).
[0024]
When the control unit 210 determines from the capacity values obtained in steps S306 and S307 that the free capacity of the RAM 212 is sufficient (“YES” in step S308), the blocks “Ab” and “Ca” to “Cc” are used. Is transmitted to the server 13 by following the same route as the previous update history and size information download request. In response, the server 13 returns the requested map data of each block, and the map data is input to the control unit 210 following the same route as the update history and size information, and is input to the control unit 210. Rewrites the map data, the update history, and the size information of each block stored in the RAM 212 based on this and the update history and the size information temporarily stored in the buffering area of the RAM 212 (step S309). .
[0025]
In this case, the control unit 210 does not transmit a map data download request for the blocks “Aa” and “Ac” to “Bc” (“matching block” in step S305). This is because these blocks do not need to be downloaded again because the information of the new and old update histories match.
[0026]
With the above processing, the latest map data of all the blocks necessary for display has been obtained, so the control unit 210 edits the contents of these map data to generate a display image (step S310), and displays this. The message is displayed on the unit 215 (step S311), and the process ends.
[0027]
On the other hand, when the control unit 210 determines in step S308 that the free space of the RAM 212 is insufficient ("NO" in step S308), the control unit 210 displays a map of the designated area to indicate that the free space is insufficient. Displays on the display unit 215 that any of the existing data in the RAM 212 must be deleted and an option for the deletion (whether or not to delete or what data should be deleted).
[0028]
On the other hand, if the operation input unit 216 selects not to select and delete the existing data in the RAM 212 (“NO” in step S313), the control unit 210 displays the map display because the free space of the RAM 212 is insufficient. The fact that the operation cannot be performed is displayed on the display unit 215 (step S315), and the process ends.
[0029]
If the operation input unit 216 selects to delete the existing data in the RAM 212 (“YES” in step S313), the control unit 210 selects and deletes a part of the existing data in the RAM 212 according to the selection. (Step S314), and then return to Step S307.
[0030]
Note that the above-described first embodiment of the present invention can be similarly implemented even when the communication terminal is wired instead of wireless.
[0031]
According to the first embodiment of the present invention, among the map data in block units required for display in the communication terminal, download of the map data stored in the internal memory with the latest contents can be omitted. And economical transmission and reception of map data.
[0032]
(Second embodiment)
Hereinafter, a second embodiment of a map data download method and a communication terminal according to the present invention will be described with reference to FIG. 6 and FIG. In the above-described first embodiment of the present invention, there is an inconvenience that it is not possible to automatically cope with a shortage of the free space of the RAM 212. According to the second embodiment of the present invention, an evaluation value is assigned to each block of the map data, and when the free space in the RAM 212 is insufficient, the map data of the block having the lower value is deleted in order. Is to improve. 1 and 2 described in the first embodiment of the present invention will be appropriately referred to in the description of the second embodiment of the present invention.
[0033]
FIG. 6A shows map data composed of 25 5 × 5 blocks. In the figure, alphabets of “A” to “E” and “a” to “e” are coordinates for each block for distinguishing each block by symbols of “Aa” to “Ee” as in FIG. . Although the map data of these blocks is stored in the RAM 212, this figure shows a case where the map data of the block "Ee" is lacking due to the limitation of the capacity. The number of each block indicates the evaluation value of each block relating to the display history. In the initial state, the evaluation value of all blocks is the minimum value “1”.
[0034]
FIG. 6B shows a state in which the 3 × 3 block at the upper left corner is designated by the operation input unit 216 and displayed on the display unit 215 in this case. In this case, the evaluation value of the designated and displayed block is set to the maximum value of “5”, the evaluation value of the block adjacent thereto is set to “4”, and the evaluation value of the immediately preceding block is set to the minimum value of “1” for the other blocks. Except in the case of, the evaluation value is decremented by one each time the display is updated. FIG. 6B shows the evaluation value given to each block based on this rule.
[0035]
Next, it is assumed that as a result of the scroll operation on the operation input unit 216, the range displayed on the display unit 215 has moved as shown in FIG. At this time, the evaluation value of each block changes as shown there based on the above-described rule.
[0036]
Similarly, the display range is further scrolled to FIG. 6D and FIG. 6E, and as a result, the evaluation value of each block becomes as shown in FIG. At this time, the map data of the missing block “Ee” must be downloaded from the server 13. However, since the free space of the RAM 212 is limited, the map data of the block having the lowest evaluation value must be deleted in advance. No. Since the block with the lowest evaluation value in FIG. 6E is “Ae”, after deleting this, the map data of the block “Ee” is newly downloaded (FIG. 6F).
[0037]
The above operation will be described with reference to a flowchart shown in FIG. 7 according to the second embodiment of the present invention. In the figure, steps S301 to S306 are common to FIG. After the size of the map data to be newly downloaded is calculated in the processing up to step S306, the evaluation value N of the block that can be deleted from the map data of the existing blocks in the RAM 212 is set to the initial value “1”. (Step S701). Subsequent confirmation of the free space in the RAM 212 (step S307) and determination of excess or shortage of the free space (step S308) are the same as those in FIG. As a result, when it is determined that the free space is insufficient ("NO" in step S308), the map data of the block having the evaluation value N or less is deleted. In this case, since the value of N is the initial value “1”, the map data of the block “Ae” is deleted from among the blocks shown in FIG. 6E (step S702).
[0038]
Next, after the value of N is increased by one (step S703), the process returns to step S307, and the free space of the RAM 212 is confirmed again. In the case of FIG. 6 (e), it is determined that the free space is sufficient (“YES” in step S308), and the process branches to step S309 to download the map data of the newly required block “Ee”, and then proceeds to step S310. The map in the designated range is displayed on the display unit 215 through the same processing as in FIG.
[0039]
The above-described rule regarding the evaluation value of a block is an example in which the evaluation value of a block that is spatially or temporally closer to the latest display area is set as a reference, and another rule based on a common concept is used. Methods (elapsed time, frequency of use, size, etc.) are of course also conceivable. Further, the deletion of stored data other than the map data may be appropriately combined.
[0040]
According to the second embodiment of the present invention, when there is insufficient memory space to download new block map data, existing map data that is unnecessary and is likely to be deleted is automatically deleted. Thus, required free space can be secured, and convenience can be further improved.
[0041]
【The invention's effect】
According to the present invention, the latest map data can be efficiently downloaded and used in response to the map data update on the server side.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of transmission and reception of map data between a server and a communication terminal according to the first or second embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a communication terminal according to the first or second embodiment of the present invention.
FIG. 3 is an operation flowchart according to the first embodiment of the present invention.
FIG. 4 is an explanatory diagram of map data update history comparison according to the first or second embodiment of the present invention.
FIG. 5 is a diagram showing an example of storage capacity allocation of a RAM according to the first or second embodiment of the present invention.
FIG. 6 is an explanatory diagram of a rule for assigning map data evaluation values for each block according to the second embodiment of the present invention.
FIG. 7 is a flowchart according to a second embodiment of the present invention.
[Explanation of symbols]
11 map 12 map data expressed in table format 13 server 14 communication terminal 201 antenna 202 transmission / reception switching unit 203 reception unit 204 transmission unit 205 modulation / demodulation unit 206 DA conversion unit and driver 207 voice-electric conversion unit and AD conversion unit 208 handset 209 Transmitter 210 control unit 211 ROM
212 RAM
213 Battery 214 Power supply unit 215 Display unit 216 Operation input unit

Claims (8)

A map data download method for a system, comprising: a server that stores map data in block units; and a communication terminal having a memory that stores a part of the map data and a communication terminal that requests the server to download the map data. ,
The server updates the map data in block units according to a change in the map, adds and stores information of the update history, and stores the update.
The communication terminal, when downloading the block-based map data from the server, receives the update history information corresponding to the block requested to be downloaded from the server, and stores the stored update history in the communication terminal. Is compared with the received update history information, and as a result, when the stored update history information matches, the stored map data is used for display without downloading, and the stored map data is displayed. If the information does not match the update history information, the map data of the block is downloaded from the server and used for display. The server further adds and stores information on the size to the map data in block units,
The communication terminal obtains information on the size of the map data to be downloaded from the server, compares the obtained information with a free space in the memory,
2. The map data according to claim 1, wherein when the free space is insufficient, the free space is secured by deleting an unnecessary portion from the stored map data in block units. How to download. The server further adds and stores information on the size to the map data in block units,
The communication terminal assigns an evaluation value to the stored map data in accordance with a predetermined criterion, obtains information on the size of the map data to be downloaded from the server, and compares the information with the free space of the memory. ,
2. The map according to claim 1, wherein when the free space is insufficient, the stored free space is secured by deleting the stored map data in block units in ascending order of the evaluation value. How to download data. The server further stores information on the size of the map data in block units,
The communication terminal assigns a higher evaluation value to the stored block-unit map data as the geographical proximity to a point or an area to be displayed and / or as a shorter elapsed time since being used for the display. And
Obtaining information on the size of the map data to be downloaded from the server and comparing it with the free space of the memory,
2. The map according to claim 1, wherein when the free space is insufficient, the stored free space is secured by deleting the stored map data in block units in ascending order of the evaluation value. How to download data. It requests the server that updates the map data in block units according to the map change and adds and stores the update history information to download the map data in block units, and from the server, downloads the map data in block units. A communication terminal that downloads map data and stores a part of the map data in a memory,
Download means for downloading the block-unit map data to which the update history information has been added from the server;
Comparing means for comparing the information on the downloaded update history with the information on the stored update history,
Display means for displaying map data;
If the result of the comparison by the comparing means matches, the stored map data is displayed without downloading, and if the result of the comparison by the comparing means does not match, the map data of the block is downloaded from the server. A communication terminal comprising: a control unit that controls the download unit and the display unit so as to display the data. In the case where information of the size of the map data in block units is further stored in the server,
Means for obtaining information on the size of the map data to be downloaded from the server and comparing it with the free space of the memory;
6. The apparatus according to claim 5, further comprising: a unit for deleting an unnecessary portion from the stored map data in block units to secure a free space when the free space is insufficient. Communication terminal. In the case where information of the size of the map data in block units is further stored in the server,
Means for obtaining information on the size of the map data to be downloaded from the server and comparing it with the free space of the memory;
Means for assigning an evaluation value to the stored map data in block units according to a predetermined criterion,
6. The apparatus according to claim 5, further comprising: means for deleting the stored map data in block units in ascending order of the evaluation value to secure the free space when the free space is insufficient. Communication terminal as described. In the case where information of the size of the map data in block units is further stored in the server,
Means for obtaining information on the size of the map data to be downloaded from the server and comparing it with the free space of the memory;
Means for assigning a higher evaluation value to the stored block-unit map data as the geographical proximity to a point or an area to be displayed and / or as a shorter elapsed time since being used for the display,
6. The apparatus according to claim 5, further comprising: means for deleting the stored block-unit map data in ascending order of the evaluation value to secure the free space when the free space is insufficient. Communication terminal as described.

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