JP2006293146A - Map server distributing map content in hierarchical structure, terminal, program, and data structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a map server, a terminal, and a program in which the load on the map server is light and the display speed of map contents can be made fast. <P>SOLUTION: The map server 1 has a map content database 12 stored with a plurality of map contents and a map content distributing means 11 of transmitting a requested 1st map content and a link address of a 2nd map content related to the 1st map content to the terminal 2 when a map content request message is received. The map content database 12 is stored with map contents in hierarchical structure, and the 2nd map content is a map content of high resolution divided into tiles for the 1st map content. The link address of the 2nd map content may designate a map server different from the map server 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a map server that distributes map content, a terminal that displays map content received from the map server, a program for the terminal, and a data structure of the map content.

  Conventionally, a plurality of map servers having different types of map contents exist on the Internet. First, a terminal accesses a map server via the Internet, receives map content in a desired area, and displays it on a display. At this time, it is assumed that the user operating the terminal scrolls or enlarges / reduces the display area. At this time, the terminal transmits the operation information to the map server. Then, the map server determines and transmits the map content to be transmitted next to the terminal based on the operation information.

  As map format image format formats, there are a vector format such as SVG (Scalable Vector Graphics) and a bitmap (raster) format. SVG is standardized by W3C, and uses XML to describe information such as line bend or thickness as text data. On the other hand, representative examples of the bitmap format include JPEG and GIF, and an image is expressed by a set of points (pixels). According to the bitmap format, when an image is enlarged, a shaggy in which an oblique line has a jagged staircase shape occurs. On the other hand, according to the SVG format, since a smooth image without shaggy is drawn at high speed and is text data, the data can be easily embedded separately, and the file size can be reduced. In particular, the SVG format is suitable for a mobile environment such as a mobile phone communication system.

Geographic Coordinate Systems, [online], [Search March 5, 2005], Internet <URL: http: //www.w3.org/TR/SVG11/coords.html#GeographicCoordinates>

  According to the prior art, the map server needs to determine map content to be transmitted to the terminal in accordance with user operation information. Such a sequence not only increases the load on the map server, but also reduces the display switching speed of the map content on the terminal. In addition, when one map server stores low-resolution map content and the other map server stores high-resolution map content, the terminal needs to switch the map server according to the resolution. However, normally, the terminal needs to know the address of the other map server in advance.

  Therefore, an object of the present invention is to provide a map server, a terminal, a program, and a data structure that can reduce the load on the map server and increase the display switching speed of map content in the terminal.

The map server of the present invention
A map content database that stores multiple map content;
Map content distribution means for transmitting the requested first map content and the link address of the second map content related to the first map content to the terminal when the map content request message is received It is characterized by having.

According to another embodiment of the map server of the present invention,
The map content database stores map content in layers,
It is also preferable that the second map content is a high-resolution map content divided into tiles with respect to the first map content.

According to another embodiment of the map server of the present invention,
The link address of the second map content points to a map server different from the map server,
The link address of the second map content preferably further includes region information for the first map content.

According to the terminal communicating with the map server of the present invention described above,
Map content acquisition means for transmitting a map content request message to the map server and receiving the first map content and the link address of the second map content;
And a map content layer storage unit that stores the first map content in a layered manner based on the link address of the second map content.

  According to another embodiment of the terminal of the present invention, the map content request message preferably requests one or more map contents having area information included in the map display area in the terminal.

  According to another embodiment of the terminal of the present invention, the map content layer storage means is used to delete map content other than the map content linked to the upper layer as viewed from the last displayed map content. It is also preferable to further have a garbage collection means.

Furthermore, according to another embodiment of the terminal of the present invention,
The map content includes valid time information,
The map content hierarchy storage means preferably instructs the map content acquisition means to acquire the map content when the effective time of the effective time information included in the map content to be displayed has already elapsed.

According to the program for causing the computer mounted on the terminal communicating with the map server of the present invention described above to function,
Map content acquisition means for transmitting a map content request message to the map server and receiving the first map content and the link address of the second map content;
The computer is made to function as a map content layer storage unit that stores the first map content in a layered manner based on the link address of the second map content.

  According to another embodiment of the program of the present invention, the map content request message preferably requests one or more map contents having area information included in a map display area in the terminal.

According to another embodiment of the program of the present invention,
It is also preferable that the computer further functions as a garbage collection unit that deletes map content other than the map content linked to the upper layer as viewed from the last displayed map content by using the map content layer storage unit.

According to another embodiment of the program of the present invention,
The map content includes valid time information,
The map content hierarchy storage unit causes the computer to function to instruct the map content acquisition unit to acquire the map content when the effective time of the effective time information included in the map content to be displayed has already elapsed. It is also preferable.

According to the present invention, in the data structure of the first map content in the SVG format used by the computer to display a map,
The data structure has a metadata tag portion related to the first map content and an image tag portion including a link address of the second map content related to the first map content,
The computer displays the first map content, and transmits a content request message based on the link address of the second content by a display operation on the first map content.

Also, according to another embodiment of the data structure of the present invention,
Map content is stored in layers,
The second map content is a high-resolution map content divided into tiles with respect to the first map content. The link address of the second map content further includes area information for the first map content. It is also preferable.

  According to the present invention, since the terminal already knows the link address of the next high-resolution map content while browsing the low-resolution map content, the load on the map server is reduced. Further, since the terminal can immediately transmit the map content request message to the link address, the display switching speed of the map content is also increased.

  According to the basic specification of SVG, the first content has a function of importing the second content and pasting it at a desired position by a hyperlink. Thereby, hyper layering is also implemented. According to the present invention, even the existing SVG browser can at least use the map content arranged in a tile shape. According to the present invention, it is possible to use tiled map content while ensuring the maximum compatibility with the SVG specification.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a hierarchical configuration diagram of tiled map content.

  According to FIG. 1, the map content is represented in the SVG format and has a structure that is hierarchized by link information from low resolution to high resolution. Map.svg is represented in the uppermost layer, and map1.svg, map2.svg, map3.jpg and map4.gif are represented in the lower layer of the map.svg. As in this example, the linked map content is not necessarily in the SVG format. However, at least the parent map content in the hierarchical structure needs to be in the SVG format. map1.svg to map4.gif are arranged in a tile shape and represent map content having a higher resolution than map.svg. Also, map11.svg to map14.svg are represented in the lower layer of map1.svg. map11.svg to map14.svg are arranged in a tile shape and represent map content having a higher resolution than that of map1.svg.

  According to FIG. 1, map.svg is described as the highest layer (low resolution) map content, but there may be a higher layer map content than map.svg. In that case, the top layer map content stored in the map content layer storage unit is further added to maintain the hierarchical structure.

  FIG. 2 is a first sequence diagram in the present invention.

(S301) The terminal 2 transmits a map content request message to the map server A that stores the desired map content map.svg. The map server A hierarchically accumulates map content from low resolution to high resolution. Further, a part of the map content configured hierarchically is stored in another map server B.

(S302) The map server A transmits the requested map content map.svg to the terminal 2, and link information to a plurality of high-resolution map contents (map1.svg to map4.gif) related to the map content. Is also transmitted to the terminal 2. This link information includes area information for the map content map.svg as well as the URL which is the address information. The area information indicates an area (range) occupied by a high-resolution map content related to the requested map content map.svg. The high resolution map content is indicated by the URL.

  For example, when the map server A transmits map.svg to the terminal 2, link information of map1.svg to map4.gif in the lower layer is also transmitted to the terminal 2. According to FIG. 2, map1.svg is in the map server B and has a URL indicating it. The terminal that has received the information displays map.svg on the display and accumulates the hierarchical structure of the map content in the map content hierarchy storage unit.

  When map.svg is displayed on the display, the user may want to view high-resolution map content for a part of the map. In that case, on the screen on which the map content is displayed, the user designates an area to be displayed next with a mouse or the like. Then, the terminal determines that higher-resolution map content can be used for display in that area, and can thereby request display of the high-resolution map content in that portion.

  For example, assume that the lower left part of the map content map.svg is specified. At this time, map.svg already contains the URL to the high-resolution map content as link information. The link information includes area information occupied by map1 to map4 for the map content map.svg. When the lower left part is designated as a new display area, the terminal can determine that map1 is content suitable for display by comparing the area information occupied by map1 to map4 with the area to be displayed next. it can. Furthermore, since the URL that is the acquisition destination of map1 is written in the previous link information, the information for acquiring the content map1 to be acquired has already been grasped.

(S303) The terminal 2 transmits a map content request message to the map server B to acquire map1.svg based on the URL.
(S304) The map server B transmits the requested map content map1.svg to the terminal 2 and also transmits link information of a plurality of map contents related to the map content to the terminal 2. For example, when map1.svg is transmitted to the terminal 2, link information of map11.svg to map14.svg of the lower layer is also transmitted to the terminal 2. The terminal that has received the information displays map1.svg on the display, and stratifies the map content and stores it in the map content layer storage unit.

  FIG. 3 is a sample source code of map.svg of the highest layer in the present invention.

  According to FIG. 3, a metadata tag <metadata> and an image tag <image> are included in an SVG tag <svg> representing map content of map.svg serving as a container. The metadata tag <metadata> is based on the SVG specification, and is configured by an RDF description that defines a geographic coordinate system (CRS: Coordinate Reference System). In the map content of the multi-layered SVG, the CRS metadata may be given only to the route, or may be given to the lower-layer map content.

  The image tag <image> indicates link information, and includes area information for map.svg and address information (URL) of high-resolution map content in the area. The area information is represented by an xy coordinate value, a width, and a height. As map content in the lower layer of map content map.svg, link information of map1.svg to map4.gif is represented. map1.svg to map4.gif may be stored in a map server different from the map server.

  In particular, according to the sample source code of FIG. 3, the SVG specification does not include any extended function. Therefore, even a browser corresponding to an existing SVG can display map contents with respect to the source code having the data structure of the present invention.

  FIG. 4 is a second sequence diagram in the present invention.

  The sequence in FIG. 4 is obtained when the processing for comparing the area information occupied by the higher-resolution content and the area to be displayed next is enhanced, and when map.svg of the upper layer is acquired as compared with FIG. In addition, the map contents of lower layer map1.svg to map4.gif are also acquired in the background. If you can predict the next scroll direction or enlargement / reduction for the map content that the user is browsing, by receiving in advance the map content one level lower and the map content next to it, It leads to increase the map display switching speed.

(S501) The terminal 2 transmits a map server address request message to the map server A storing the desired map content map.svg.
(S502) The map server A transmits the requested map content map.svg to the terminal 2, and also transmits to the terminal 2 link addresses of a plurality of map contents related to the map content. This link information includes area information for the map content map.svg. For example, when transmitting map.svg to terminal 2, the link addresses of map1.svg to map4.gif in the lower layer are also transmitted to terminal 2.

(S503) The terminal 2 displays map.svg and also tries to acquire map1.svg to map4.gif having a higher resolution by one layer than that in the background. The terminal 2 transmits a map content request message to the URL 1 of the map server A in order to acquire the map contents of map1.svg to map4.gif.
(S504) The map server A transmits map2.svg to map4.gif to the terminal 2. At this time, the map server A transmits the link address of the map content of the lower layer to the terminal 2 for each of map2.svg to map4.gif. The terminal 2 stores map2.svg to map4.gif hierarchically with respect to map.svg in the map content layer storage unit.

(S505) Further, the terminal 2 transmits a map content request message to the URL 2 of the map server B in order to acquire map1.svg.
(S506) The map server B transmits map1.svg to the terminal 2. At this time, the map server B also transmits the URL of the map content in the lower layer of map1.svg to the terminal 2. The terminal 2 stores map1.svg hierarchically in the map content layer storage unit with respect to map.svg.

  Through S503 to S506, map1.svg to map4.gif, which are lower layers of map.svg, can be stored at once in the map content hierarchy storage unit. That is, when the user is browsing map.svg, the lower-layer map content having the high resolution is already stored in the map content layer storage unit.

  Here, it is assumed that the user clicks the range portion of map1.svg in the displayed map.svg with a mouse or the like, and requests the high-resolution map content of that portion. At this time, the map content map1.svg has already been received from the map server B in S506 and stored in the map content hierarchy storage unit. Therefore, the map content map1.svg can be immediately displayed on the display, and an extremely high display switching speed can be realized.

(S507) The terminal 2 has already received the URL in the map content in the lower layer of map1.svg in S506. Therefore, the terminal 2 can transmit a map content request message to the map server in the background. Map11.svg to map14.svg in the lower layer of map1.svg are stored in the map server B. Accordingly, the terminal 2 transmits a map content request message to the map server B.
(S508) The map server B transmits map11.svg to map14.svg to the terminal 2. At this time, the map server B also sends the link address of the lower layer map content to the terminal 2. The terminal 2 stores map11.svg to map14.svg hierarchically in the map content layer storage unit with respect to map1.svg. It should be noted that to what level the map content is acquired in the background should be adjusted according to the capacity of the hierarchical storage unit and the communication capacity.

  According to the sequence of FIG. 4, each time the user scrolls or enlarges the display area with respect to the map content displayed in the browser, the terminal sends a map content request message to one or more map servers. Send and receive map content. At this time, not only the map content to be displayed but also the low-resolution map content of the map content is downloaded. The received map content is hierarchically organized one after another and stored in the map content layer storage unit.

  FIG. 5 is a functional configuration diagram of the map distribution system according to the present invention.

  According to FIG. 5, the map servers A and B and the terminal 2 are connected via the Internet 4.

  The map server 1 includes a map content distribution unit 11 and a map content database 12.

  The map content database 12 stores map content in a hierarchy from low resolution to high resolution. According to FIG. 5, the map content database 12 of the map server A stores map.svg, but does not store the high-resolution map1.svg. Only the link address of map1.svg is stored. The link address points to the map server B.

  The map content distribution unit 11 receives a map content request message from the terminal 2, searches for map content using the map content database 12, and transmits the map content to the terminal 2. At that time, the map content distribution unit 11 also transmits the link address in the lower layer of the map content to the terminal 2.

  The terminal 2 includes a map content acquisition unit 21, a map content hierarchy storage unit 22, a display display unit 23, a garbage collector unit 24, and an effective time determination unit 25.

  The map content acquisition unit 21 transmits a map content request message to the map server 1 and receives the map content. The map content layer storage unit 22 stores the map content received from the map server 1 in a hierarchical manner. The display display unit 23 acquires map content from the map content hierarchy storage unit 22 and displays the map content on the display 26.

  FIG. 6 is an explanatory diagram of the operation of the garbage collector 24 in the present invention.

  The terminal accumulates the received map contents one after another in a hierarchical structure. Thus, when the map content being browsed is displayed again after the map content being browsed is enlarged and reduced, by using the map content already stored in the map content hierarchy storage unit, The display switching speed can be realized at high speed. However, in such a method, useless map content that is not displayed by the terminal for a long period of time is also stored in the map content layer storage unit. Therefore, it is necessary to delete the map content that is less necessary by the garbage collector every time a certain time elapses and to secure the free space of the storage unit.

  The upper part of FIG. 6 represents the state stored in the map content hierarchy storage unit. Although map11.svg is displayed here, map2.svg to map4.gif and map12.svg to map14.svg are also accumulated.

  The lower part of FIG. 6 represents the state stored in the map content hierarchy storage unit after the garbage collector unit 24 operates. Here, only the map content map1.svg on the link from the currently displayed map.11.svg to the top layer map.svg is accumulated. That is, only the map content that is the direct parent as viewed from the currently displayed map11.svg remains. Accordingly, all map contents other than those on the link have been deleted. However, it is preferable not to delete the map content in the vicinity in the coordinate space with respect to currently displayed map11.svg. This is because there is a high possibility that display is required immediately after. Therefore, it is preferable to delete the map contents in order from the map 11.svg that is currently displayed, which is far from the coordinate space.

  FIG. 7 shows sample source code used in the valid time determination unit 25 in the present invention.

  According to FIG. 7, there are a first case in which valid time information is included in the metadata tag <metadata> and a second case in which valid time information is included in the image tag <image>. For the map content specified by the valid time information, if the valid time has passed, the map content request message is transmitted to the map server again even if it is accumulated in the map content hierarchy accumulation unit of the terminal. According to FIG. 7, the valid time is described in the wallclock-value, and it is determined by whether or not the time from the creation date / time of the map content to the current date / time is within the valid time. In this manner, new map content can be provided to the user by adding the valid time information to the source code in the SVG format.

  FIG. 8 is a diagram illustrating the operation of the browser that displays the tiled map content.

  The display range of the browser of the terminal is not always represented by one map content. According to the view box 1 of FIG. 8, it is represented by map31.svg to map34.svg. In this way, a plurality of map contents may be displayed in the display range of the browser. At this time, when the display range moves to the view box 2, it is represented by map13.svg, map14.svg, map31.svg, and map32.svg.

  Here, if the display range of the browser tries to display outside the range of the accumulated map content, it becomes blank. In such a case, the map content of the lower layer can be acquired by returning to the map content of the higher layer. In addition, a link address of a map content to be newly set as a route can be described in the metadata, and the map content can be acquired upon departure.

  FIG. 9 shows sample source code for switching map contents according to the magnification displayed on the browser.

  The sample source code in FIG. 9 is for precise control by adding display control information to the content regarding processing for comparing the region information occupied by higher-resolution content and the region to be displayed next. is there. In this code, information for enabling the display of the map content to be precisely switched in accordance with the magnification displayed by the browser as a control parameter is expanded. Since the drawing information is based on XML, such expansion is easy.

  According to FIG. 9, when the value of the attribute au: figure-visibility representing the display magnification is 200 or more, it is represented by high resolution map1.svg, map2.svg, map3.jpg, map4.gif, In between, it is represented by the low resolution map.svg itself.

  According to the present invention, since the terminal always accurately grasps the display magnification when browsing low-resolution map content, the terminal can accurately determine the next high resolution from the display magnification. It is possible to control the timing of displaying the map content, and to reflect the intention of the content provider more precisely. And since the link address of the map content is already known, the load on the map server is small. In addition, since the terminal can immediately transmit a map content request message to the link address, the display switching speed of the map content is fast.

  According to the above-described various embodiments of the present invention, those skilled in the art can easily make various changes, modifications, and omissions in the technical idea and scope of the present invention. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

It is a hierarchical block diagram of the tiled map content. It is a 1st sequence diagram in this invention. It is a sample source code of map.svg of the highest layer in the present invention. It is a 2nd sequence diagram in this invention. It is a functional block diagram of the map delivery system in this invention. It is operation | movement explanatory drawing of the garbage collector part in this invention. It is a sample source code used in the effective time determination part in this invention. It is operation | movement explanatory drawing of the browser which displays the tiled map content. This is sample source code for switching map contents according to the magnification displayed in the browser.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Map server 11 Map content delivery part 12 Map content database 2 Terminal 21 Map content acquisition part 22 Map content hierarchy storage part 23 Display display part 24 Garbage collector part 25 Effective time determination part 26 Display 4 Internet

Claims (13)

A map content database that stores multiple map content;
Map content distribution means for transmitting the requested first map content and the link address of the second map content related to the first map content to the terminal when the map content request message is received; A map server characterized by comprising: The map content database stores the map content in a hierarchy,
The second map content is a high-resolution map content divided into tiles with respect to the first map content,
The map server according to claim 1, wherein the link address of the second map content further includes area information for the first map content.   The map server according to claim 1 or 2, wherein the link address of the second map content indicates a map server different from the map server. A terminal that communicates with the map server according to any one of claims 1 to 3,
Map content acquisition means for transmitting the map content request message to the map server and receiving the first map content and a link address of the second map content;
A terminal comprising map content hierarchy storage means for storing the first map content in a hierarchy based on a link address of the second map content.   The terminal according to claim 4, wherein the map content request message requests one or more map contents having area information included in a map display area in the terminal.   2. The apparatus according to claim 1, further comprising: a garbage collection unit that deletes map content other than the map content linked to an upper layer when viewed from the map content displayed last using the map content layer storage unit. The terminal according to 4 or 5. The map content includes valid time information,
The map content layer storage means instructs the map content acquisition means to acquire the map content when the effective time of the effective time information included in the map content to be displayed has already passed. The terminal according to any one of claims 4 to 6, characterized in that: A program for causing a computer mounted on a terminal that communicates with the map server according to any one of claims 1 to 3 to function,
Map content acquisition means for transmitting the map content request message to the map server and receiving the first map content and a link address of the second map content;
A program that causes a computer to function as a map content layer storage unit that stores the first map content in a hierarchy based on a link address of the second map content.   9. The program according to claim 8, wherein the map content request message requests one or more map contents having area information included in a map display area in the terminal.   The computer further functions as a garbage collection unit that deletes map content other than the map content linked to an upper layer when viewed from the map content displayed last using the map content layer storage unit. The program according to claim 8 or 9. The map content includes valid time information,
When the effective time of the effective time information included in the map content to be displayed has already elapsed, the map content hierarchy storage unit instructs the map content acquisition unit to acquire the map content. The program according to any one of claims 8 to 10, which causes a computer to function. In the data structure in the first map content in the SVG format that the computer uses to display the map,
The data structure includes a metadata tag portion related to the first map content and an image tag portion including a link address of a second map content related to the first map content.
The data structure, wherein the computer displays the first map content and transmits a content request message based on a link address of the second content by a display operation on the first map content. The map content is layered,
The second map content is a high-resolution map content divided into tiles with respect to the first map content,
The data structure according to claim 12, wherein the link address of the second map content further includes area information for the first map content.

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