JP2000048039A - Download method for map information and download system for map information executing the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To download map information in a short time by downloading only map data required for displaying new map data among map data held at present through a host computer. SOLUTION: On the side of a client computer, a 'map display program' holds the map information in areas 1 and 2 and reports the need of a map information area 3 to a 'map managing program'. The 'map managing program' extracts map information, which is not held by the 'map display program' in the part of the area 3 from a map database and transmits it to the 'map display program'. The 'map managing program' of the host computer transmits only the map information, for which the 'map display program' is lacked, to the 'map display program'. The 'map display program' receives 'map information', adds a map display primitive to the relevant display scale layer and registers the display primitive in the divided area of the relevant display scale layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a map information download method for downloading map information from a map database of a host computer to a client computer through a network, and displaying the map information on the client computer, and a map implementing the method. Information download system. A map information download method and a map information download system according to the present invention, when downloading map information from a host computer to a client computer, reduce the amount of download information and perform quick download. .

[0002]

[Problems to be solved by the invention]

2. Description of the Related Art Recently, with the development of digital communication networks such as ISDN, information networks using computers, such as the Internet, are rapidly spreading. In information networks such as the Internet, not only text data such as characters but also image data such as photographs and maps are used. Since the amount of information of image data is much larger than that of text data, it usually takes a long time to transmit image data through a network.

FIG. 7 is a system configuration diagram showing an example of a map information download system using a network. In FIG. 7, reference numeral 10 denotes a host computer for managing map information. The host computer 10 has a map information database 12 and a map management program 11 therein. Reference numeral 20 denotes a client computer for displaying map information, and reference numeral 21 denotes a display device. The client computer 20 has a map display program 22 therein, downloads map information from the host computer 10 in accordance with a user's instruction by the program 22, and displays the map information on the display device 21. 30
Is an information network such as the Internet. The host computer 10 and a plurality of client computers 20 are connected to the network 30 to form a map information network.

In a map information network having such a configuration, a user who requests map information uses a client computer 20 to operate a host computer 10.
Visit to download the required map information,
The map information is obtained by displaying and browsing on the display device 21. In this case, usually, until the necessary map information required by the user is obtained, a change of the display area, a change of the density of the displayed map, and the like are repeated. Each time the map information requested by the user is changed, the client computer 20 accesses the host computer 10, downloads the necessary map information, and repeatedly performs the operation of displaying the map information on the display device 21. However, since the map information is image data, the amount of data is large, and the client computer 20 of normal capability requires a long waiting time until one piece of map data is downloaded and displayed on the display device 21.

To reduce the waiting time, the capacity of the client computer 20 has been improved. However, no matter how much the capacity of the client computer 20 is improved, the capacity of the network 30 is limited.
It was not possible to reduce this waiting time beyond a certain time. In particular, when many computers are accessing the network 30, there is a problem in that the amount of data transmitted on the network increases and the waiting time increases.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem of downloading map information, and uses a client computer having a normal capacity to transmit data to a host computer via a network having a relatively high communication density. It is an object of the present invention to realize a map information download method and a map information download system that can execute map information download with a short waiting time even when accessed.

[0007]

According to the present invention, a map information download method and a map information download system which implements the method create map data of a host computer in a hierarchy corresponding to a display scale. The minimum display unit for displaying map data of each scale display scale on the map, such as rivers, railways, hospitals, administrative districts, place names, and station names, has been standardized to facilitate access from client computers. At the same time, the client computer holds the map data once downloaded from the host computer, and if the user instructs to change the display of new map data, the client computer Only the map data necessary to display the new map data By reducing the amount of map data to be downloaded in such a way as to download the map information from the data, the transmission time of the network data is shortened and the data processing time of the client computer is shortened. This realizes a map information download system capable of downloading.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 illustrates the configuration of a "map database" of a host computer used in a map information download system of the present invention and a map data management method of a "map management program" for managing the configuration. FIG. In FIG. 1, DT indicates a display scale layer of a map database. DP0 indicates a data display primitive for displaying map data of the display scale layer 0, DP1 indicates a data display primitive for displaying map data of the display scale layer 1, and DP
2 shows a data display primitive for displaying map data of the 2 display scale layer 2.

The data in the map database of the host computer is classified and stored in a plurality of levels of display scale layers according to the display density of the map to be displayed. The display scale layer refers to, for example, “20
A layer adapting from "1 / 100,000" to "1 / 500,000" is defined as a display scale 0 layer, and a layer adapting from "1 / 500,000" to "1/15000" is defined as one display scale layer. It is divided into layers according to the size of a certain scale. Each display scale layer is composed of appropriate display units for displaying a map of the layer. In the "map database", display units of map data are stored by being classified for each display scale layer, and display units of map data are classified and managed by a "map management program".

A display unit is a minimum element for displaying on a map, such as a river, a railway, a hospital, an administrative district, a place name, and a station name. Each display element is added with position data displayed in a display scale layer. Have been. This is hereinafter referred to as a display primitive. Display primitive DP of display scale layer 0
0 has a display primitive 1, a display primitive 2, and a display primitive 3 corresponding to each of the divided display areas. The display primitive DP1 of the display scale layer 1 has display primitives 5, display primitives 6, display primitives 7 corresponding to the respective divided display areas.
have. Similarly, the display primitive DP2 of the display scale layer 2 has a display primitive 8, a display primitive 9, and a display primitive 10 corresponding to each of the divided display areas.

Therefore, the download of the map information is performed by designating a specific display primitive corresponding to the area of the display scale layer of the map to be displayed. FIG. 2 is a diagram for explaining a relationship between a divided area of each display scale layer of the map database of the host computer and a display primitive used in the map information download system of the present invention. * Regarding Area Division of Display Scale Layer and Relationship Between Scales The display scale layer 0 is divided into nine areas 01 to 09, for example, as shown in FIG. Each of the nine areas of the display scale layer 0 divided into nine parts is shown in FIG.
(B) corresponds to the next display scale layer 1. The display scale layer 1 conceptually exists as many as the area division number of the display scale layer 0. The meaning of “conceptually present” means that in a certain area of the display scale layer 0, if the display primitive does not exist in the lower display scale layer, the display scale layer does not need to be present in this area, and It means that it exists as a display scale layer. As for the display scale layer, the relationship between the display scale layer 1 and the display scale layer 2 is repeated by the number of display scale layers as shown in FIG.

Each divided area of each display scale layer holds reference information of a display primitive existing in that area. For display primitives that span multiple sub-regions,
It is registered in a plurality of divided areas. Downloading and displaying map data from a map database having such a configuration is performed by designating a display scale layer and designating a specific region of the display scale layer. The specific procedure for downloading the map data is performed as follows. (1) The display scale layer is determined from the designated display scale. (2) The divided area of the designated area in the corresponding display scale layer is determined. (3) The display primitive belonging to the corresponding divided area is extracted. (4) The processes (2) to (3) are performed on the layer above the corresponding display scale layer.

In this case, depending on the display primitive,
In some cases, it is not appropriate to display at the specified scale. For example, a shoreline needs to maintain the same shoreline at an appropriate resolution for each display scale layer. For this reason, the extraction of the map data is controlled according to the designated display scale. Next, a map data management method of the "map display program" on the client computer side will be described. The map data management method of the "map display program" operating on the client computer is basically the same as that of the "map information management program" on the host computer side. The difference between the program and the map data management on the client computer is as follows.
Is a point. -"Map information management program" on the host computer
Holds all map information, whereas the "map display program" on the client computer side holds some map information centered on the current display area. The client computer manages the map area held by the "map display program" for each display scale layer in a form such as a polygon.

Therefore, from the client computer,
The data request method of the "map display program" to the host computer is performed by the following steps. (1) The "map display program" on the client computer side includes a display scale layer necessary for the "map display program" to display when it is necessary to update display map information by an operation of a user who is a viewer. And a display area. (2) The "map display program" on the client computer uses the display scale layer and display area to be displayed from now on, as well as the area in each display scale layer currently held by the "map display program" on the "map" of the host computer. Information management program ".

FIG. 3 is a diagram illustrating an example of a method of requesting missing map information from the client computer to the "map management program" of the host computer. In FIG. 3, is the map information of the area already held by the "map display program" on the client computer side.
Is a map information area required by the "map display program" on the client computer side to display a map of a new area. The area range already held by the "map display program" on the client computer side,
The necessary area range due to the movement and scale change is transmitted to the "map management program", and the "map management program" of the host computer determines a lacking portion, and transmits the corresponding map information to the "map display program".

The "map display program" on the client computer side holds map information of an area of
To the "map management program" that the map information area is required. The "map management program" extracts from the map database map information that is not held by the "map display program", and
Send to (3) The "map management program" of the host computer is the "map display program" of the client computer
And sends only the map information for which the "map display program" is insufficient to the "map display program". (4) The "map display program" receives the "map information" from the "map management program", adds a map display primitive to the corresponding display scale layer, and registers the display primitive in a divided area of the corresponding display scale layer. .

A display primitive extending over a plurality of divided areas is registered in the plurality of divided areas. If the display scale layer has not been created, the registration process is performed after the display scale layer is created. In this case, the "map display program" on the client computer side displays a map at an appropriate position using the currently stored map information and, at the same time, receives each map information element without waiting for reception of all map information of the received map information. Map display processing to sequentially display on the
And the map information receiving process from the host computer in parallel, the display of the map and the reception of the map information can proceed simultaneously, and the new map information can be displayed with a short waiting time.

In the above description, the "map display program" on the client computer requests the "map management program" on the host computer for the map area to be displayed, so that the "map display program" on the client computer requests the map area. This is an example in which map data corresponding to the selected area is fetched from a map database and sequentially transmitted to a "map display program". The method of downloading map data is not limited to such a method, and a “map display program” on the client computer, as described below, may be insufficient in the map display area due to the map display area change. It is also possible to use a method of notifying the "map management program" of the host computer of the map area being processed.

FIG. 4 shows a client computer.
FIG. 11 is a diagram illustrating another example of a method of requesting the map lacking information from the “map management program” of the host computer. In FIG. 4, is the map information of the area already held by the “map display program” on the client computer side, and is the “map display program” on the client computer side to display a map of the new area. Is a map information area. "Map display program"
Requests from the "map management program". The map area information is an area representing and and includes an expression by a polygon and an expression divided by a triangle.

(1) From the map information area held by the "map display program" of the client computer, an insufficient area for an area required by movement and scale change is obtained by the "map display program".
It is determined that a map information area is required. Request the corresponding map information from the "map management program" of the host computer. (2) The “map management program” of the host computer transmits the corresponding map information to the “map display program”. As a result, the amount of work to be processed by the host computer is reduced, so that the time required for downloading can be reduced. However, since the amount of work of the client computer increases accordingly, it is necessary to take advantage of this advantage. Requires the use of more capable client computers.

Next, an explanation will be given of the operation in the case where the contents of the map are reduced by changing the scale of the displayed map. FIG. 5 shows the contents of the map from the client computer to the "map management program" of the host computer. It is a figure explaining other examples of a lack map information request method in the case of performing reduction processing. In FIG. 5, is the map information of the area already held by the "map display program" on the client computer side, and is the client computer for displaying the map of the requested map information area in the case of new reduction processing. This is the map information area required by the "map display program" on the side.

(1) From the map information area held by the "map display program" of the client computer, the insufficient area for the area to be the requested map information area in the case of the reduction process by changing the scale is defined as " It is determined by the "map display program" and it is determined that the map information area is required. Request the corresponding map information from the "map management program" of the host computer. (2) The “map management program” of the host computer transmits the corresponding map information to the “map display program”.

The client computer manages the map area held by the "map display program" for each display scale layer in a form such as a polygon. FIG. 6 is a diagram for explaining a method of managing the map area of the "map display program" of the client computer. As shown in FIG.
The “map display program” manages the management of the currently held map area by grid division of the map, and transmits a request for an insufficient map area due to movement and scale change to the “map management program” as grid information. The management of the map area is managed by the flag array information or an area number string indicating the area position,
It is managed by an index number string or the like. By managing the map area in this way, when downloading the map data, when requesting the map area to be displayed from the “map management program” on the host computer side, or the “map display program” on the client computer side, A map management program on the host computer that maps the missing map area in the map display area associated with the map display area change
The management of the map area such as notification to the user can be easily performed.

[0024]

As is apparent from the above description, the map information download method and the map information download system of the present invention divide the map data of the host computer into layers according to the display scale. In addition to creating, the river,
The minimum display unit for displaying on maps such as railways, hospitals, administrative districts, place names, and station names is standardized to enable easy access from client computers. Keep the downloaded map data, and if the user instructs to change the display of the new map data, to display the new map data on the currently held map data By downloading only the necessary map data from the host computer and reducing the amount of map data to be downloaded, the transmission time of network data is reduced and the data processing time of the client computer is reduced. Download map information in a short waiting time It is possible to perform de.

Therefore, according to the present invention, even when a host computer is accessed via a network having a relatively high data density by using a client computer having a normal capacity, map information can be saved with a short waiting time. Since downloading is possible, a system with a large practical value can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a configuration of a map database of a host computer used in a map information download system of the present invention and a map data management method of a “map management program” for managing the configuration; .

FIG. 2 is a diagram for explaining a relationship between a divided area of each display scale layer of a map database of a host computer and a display primitive used in the map information download system of the present invention.

FIG. 3 is a diagram illustrating an example of a method of requesting missing map information from a client computer to a “map management program” of a host computer.

FIG. 4 is a diagram illustrating another example of a method of requesting missing map information from a client computer to a “map management program” of a host computer.

FIG. 5 is a diagram illustrating another example of a method of requesting missing map information in a case where the content of a map is reduced from a client computer to a “map management program” of a host computer.

FIG. 6 is a diagram illustrating another example of a method of managing a map area of a “map display program” of a client computer.

FIG. 7 is a system configuration diagram showing an example of a map information download system using a network.

[Explanation of symbols]

DT: Display scale layer of map database, DP0: Data display primitive for displaying map data of display scale layer 0, DP1: Display of map data of display scale layer 1 , A data display primitive for displaying the map data of the display scale layer 2,..., Map information of an area already held by the “map display program” on the client computer side, ... A map information area required by a "map display program" on the client computer side to display a map of a new area, 10 a host computer for managing map information, 11 a map information database , 12: Map management program, 20: Client for displaying map information DOO computer, 21 ... display, 22 ... map display program, information network, such as 30 ... Internet

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C032 HB05 HB31 5B050 BA17 CA05 CA07 CA08 FA02 GA08 5B075 KK03 KK07 KK13 KK25 KK33 KK37 ND03 ND06 ND35 NR02 NR12 PP30 PQ02 PR03 QP05 UU14

Claims (5)

[Claims] In a system in which required map data is downloaded from a map database of a host computer to a client computer via a network and displayed, a user instructs the client computer to display new map data. If there is, for the currently held map data, only the map data necessary for displaying new map data is downloaded from the host computer,
A method for downloading map information that reduces the amount of map data to be downloaded. 2. Map data of a host computer is created in a plurality of hierarchies according to a display scale.
The map data of the display scale of each level is classified and stored for each area as a set of display units for displaying on the map such as rivers, railways, hospitals, administrative districts, place names, station names, etc. According to the instruction, the map data is downloaded from the host computer by specifying the display scale hierarchy and the region, and the map data is displayed by holding, and the client computer is instructed by the user to change the display of the new map data. If there is, only the map data necessary to display new map data for the currently held map data is downloaded from the host computer, reducing the amount of map data to be downloaded. How to download map information. 3. A map data download system in which necessary map data is downloaded from a map database of a host computer to a client computer via a network and displayed, and a user changes the display of new map data. Means for obtaining the difference map data between the map data currently held by the client computer and the map data necessary for displaying new map data, only the difference map data Means for downloading from the host computer to the client computer, display means for displaying new map data using the downloaded difference map data and the map data currently held by the client computer, Download Temu. 4. A method for creating a plurality of hierarchies according to a display scale and displaying map data of a display scale of each hierarchy on a map such as a river, a railway, a hospital, an administrative district, a place name, and a station name. A map database of the host computer, which is classified and held for each region as a set of display units,
A map data display means of a client computer which downloads and stores map data from a host computer and displays the map data by designating a display scale hierarchy and a region in accordance with a user's instruction; Means for obtaining map data of the difference between the map data currently held by the client computer and the map data necessary for displaying new map data when a display change instruction is given; Means for downloading only data from the host computer to the client computer, display means for displaying new map data using the downloaded difference map data and the map data currently held by the client computer, a map comprising: Information download system. 5. The map data is classified into a plurality of display scale layers according to a display density of a map to be displayed, and each display scale layer is for displaying a map of the layer.
The smallest element to be displayed on the map, such as rivers, railways, hospitals, administrative districts, place names, and station names.Each display element is made up of display units with position data added in the display scale layer. The map database of the host computer where the display unit of the map data is classified and managed by the map management program, and the map data is downloaded and held from the host computer by specifying the display scale hierarchy and region according to the user's instruction. Means for displaying map data of a client computer having a map display program for displaying map data, and when the user instructs to change the display of new map data, the map data currently held by the client computer And the difference between the map data required to display the new map data Means for determining a display unit of Figure,
Means for downloading the display unit of the difference map data from the host computer to the client computer, a new map using the display unit of the downloaded difference map data and the display unit of the map data currently held by the client computer A map information download system comprising display means for displaying data.