KR20080079344A - Geographic information data coding and decoding system and method thereof - Google Patents

Abstract

A system and a method for compressing/decompressing geographic data are provided to enhance precision of the decompressed data and minimize distortion of the decompressed data by storing real coordinates without compressing data out of a reducible range among facilities out of a setting range of a tile section for fixing reference coordinates. A database server(300) stores original geographic data. A service server(100) generates tile unit compressed data of each layer by reading the original geographic data and provides the tile unit compressed data to a client(200) connected on the network. The service server includes a storing part(120) and a controller(110). The storing part stores a tile size of each layer and reference coordinates for generating the original geographic data in a tile unit, and the geographic data compressed in the tile unit according to the tile size and the reference coordinates. The controller provides online connection with the database server and the client, generates the tile unit compressed data from the original geographic data read from the database server according to environment setting data, and provides the tile unit compressed data to the client. A communication unit(320) provides original geographic data, which are stored at a storage unit(310), to the service sever by connecting to the service sever.

Description

GEOGRAPHIC INFORMATION DATA CODING AND DECODING SYSTEM AND METHOD THEREOF}

1 is an overall configuration diagram of a geospatial data compression and decompression system according to an embodiment of the present invention.

2 is a flowchart illustrating a method of compressing geographic data according to an embodiment of the present invention.

3 is a flowchart illustrating a method of restoring compressed geospatial data according to an embodiment of the present invention.

4 is an exemplary view of a storage format for compressing and storing geographic data according to an embodiment of the present invention.

The present invention relates to a system and method for compressing and restoring geospatial data, and more particularly, to compress and transmit geospatial data by using a combination of relative and absolute coordinates, and to restore the speed of a geospatial data transmission service through restoration. The present invention relates to a geospatial data compression and decompression system and a method for improving and increasing the restoration rate of received geospatial data.

In order to provide geographic information service to a user of a client in a server-to-client environment connected by a network or a wireless network, a server compresses vector data of a topographic map and a facility to a client, and the client receives it. And restore and display on the screen.

At this time, the server reduces the size by using various compression techniques in order to speed up the transmission speed of the geospatial data provided to the client.

The method of compressing geospatial data is to compress the image file itself using the topographic map as an image, to compress by reducing the number of coordinate points in compressing vector data, and to reduce the number of bytes to store vector data. It is divided into ways.

The method of reducing the number of bytes for storing the vector data is to reduce the data storage size by converting the absolute coordinates of the facility into relative coordinates with respect to a specific reference coordinate.

To this end, data is reduced by setting a tile area for holding reference coordinates for each geographic information data and storing relative coordinates from the reference coordinates.

In this case, there may be a method of cutting and storing a facility with respect to intersection coordinates covering a tile area among data and compressing the same as it is.

In the former case, when the border region of the tile region is a polygon, it is truncated and displayed by the tile region. In the latter case, data distortion occurs when the coordinate value is out of a range capable of condensing data.

In the conventional compression method, the compression ratio is increased by compressing only the integer part of the coordinates, but there is a disadvantage that the accuracy is insufficient to be used as GIS data.

The present invention has been made to solve the above-described problems, the object of the present invention is to compress the actual coordinates as it is without compressing the data out of the condensable range of the facilities outside the set range of the tile area for holding the reference coordinates By using the storage method, the proposed method provides a method of increasing the accuracy of the reconstructed data and minimizing the distortion rate.

In addition, an object of the present invention is to provide a method of increasing the accuracy of data even if the compression ratio is slightly reduced by compressing and restoring to two decimal places.

Geographic information data compression system according to a feature of the present invention for achieving the above object,

A database server for storing original geographic data;

And a service server that reads the original geographic information database from the database server, generates compressed data in units of tiles for each layer, and provides the compressed data to clients connected online.

In addition, the geographic information data restoration system according to a feature of the present invention,

A storage unit configured to store configuration data for restoring data compressed on a tile basis and data restored on a tile basis;

Requesting the online connected service server to transmit the compressed geospatial data in units of tiles, and restoring the compressed geospatial data received according to the configuration data including tile area size, reference coordinate value, and internal precision. Control unit;

And a display unit for displaying the geographic information restored by the control unit.

In addition, the method for compressing geographic information data according to an aspect of the present invention,

(a) setting the tile size and the reference coordinates (X1, Y1) according to the configuration data, setting a multiplier value according to the tile size, and storing the tile header data;

(b) extracting relative coordinate values by reading absolute (X, Y) in the tile area from the original data, and determining whether the relative coordinate value is within a compressible range of 2 bytes;

(c) calculating and compressing the integer part by multiplying the integer part and the fractional part respectively when the relative coordinate value is a compressible range of 2 bytes, and multiplying the variable set to the absolute coordinate value when the relative coordinate value is not compressible by 2 bytes. And;

(d) repeating the steps (b) and (c) to compress and store the geospatial data for all tile areas and layer-specific areas.

In addition, the method for restoring geographic information data according to an aspect of the present invention,

(a) reading the environmental information included in the tile size and reference coordinate value of each layer for decompressed compressed data, and waiting for a request for retrieving data;

(b) setting tile information for each layer when a request for inquiry of data is detected, and reading reference coordinate values and multipliers included in header information of tile compression data received from a service server;

(c) reading a coordinate value of the original data included in the received tile compressed data to determine whether the value is compressed to 3 bytes;

(d) extracting the coordinate value by restoring the integer part and the fractional part information if the value is compressed to 3 bytes, and extracting and displaying the coordinate value by restoring only the integer part if the value is compressed to 4 bytes.

In addition, the method of compressing and restoring geographic information data according to an aspect of the present invention,

A first step of setting a tile area and a reference coordinate value for compressing original geographic data according to environment setting information, and setting an internal precision according to the tile area;

A second step of generating compressed data using relative or absolute coordinates according to whether the layer can be compressed to internal precision and relative coordinates by layer of tile area of the original geographic information data;

And reconstructing and displaying the generated compressed data for each tile area into original data according to environment setting information including tile area size, reference coordinate value, and internal precision.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

In addition, when a part is said to "include" a certain component, this means that it may further include other components, except to exclude other components unless otherwise stated.

In addition, the term module described herein refers to a unit for processing a specific function or operation, which may be implemented in hardware or software, or a combination of hardware and software.

Now, a geospatial data compression and decompression system and method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is an overall configuration diagram of a geospatial data compression and decompression system according to an embodiment of the present invention.

As shown, the present invention is a database server 300 for storing the original geographic information data for facility maps and topographic maps, and compressed data in tile units by reading the original geographic information database from the database server 300 The service server 100 generating and generating the compressed data of the tile unit to the client 200, and the service server 100 receives and restores the compressed data through a network or a wireless network, and restores the restored geospatial data. Client 200 to display.

The database server 300 includes a storage unit 310 for storing original geographic information data such as facility maps and topographic maps, and original geographic data stored in the storage unit 310 online with the service server 100. It includes a communication unit 320 to access and then provide to the service server 100.

The service server 100 stores configuration data about tile size and reference coordinate information for each layer for generating original geographic data as tiles, and stores geospatial data compressed in units of tiles according to the configuration data. Provides online connection with the storage unit 110 and the database server 300 and the client 200, and compresses the original data read from the database server 300 according to the configuration data of the storage unit 110. And a controller 120 to provide tile compression data to the client 200.

The controller 120 includes a tile compression data generation unit 121 for generating original geographic information data such as facility maps and topographic maps as tile-based compressed data according to environment setting data, a client 200, and a database server 300. ) And a tile compression data providing unit 122 which provides the tile compression data stored in the storage unit 110 to the client 200 to which the communication unit 123 is connected.

The client server 200 may include a storage unit 210 for storing configuration data for restoring data compressed in units of tiles and data restored in units of tiles, and an online connection with the service server 100. A control unit for requesting transmission of the compressed data in units of tiles to the user and restoring the compressed data received according to the transmission request according to the configuration data and displaying the same to the user, and storing the compressed data in the storage unit 210 ( And a display unit 230 for displaying the restored geospatial data so that the user can recognize it.

The control unit 220 is connected to the service server 100 online and transmits a request signal of the tile compressed data to the service server 100, accordingly the communication unit for receiving the compressed data in units of tiles provided by the service server 100 221, a tile compressed data request unit 222 for requesting the compressed data in units of tiles to the service server 100, a compressed data recovery unit 223 for restoring the compressed data, and a display unit for displaying the restored data ( And a display driver 224 for displaying on 230.

Hereinafter, a method of compressing geographic information data according to an embodiment of the present invention will be described in detail with reference to the flowchart shown in FIG. 2.

The control unit 120 in the service server 100 reads environment setting data for tile size and reference coordinate information for each layer for compressing geographic information data stored in the storage unit 110 (S101).

Then, in order to generate compressed data for each tile area for each layer to be compressed, the size of the tile and the reference coordinate values (X1, Y1) of the corresponding tile are set (S102), and a multiplier value according to the size of the tile is set ( S103).

The multiplier value according to the size of the tile is set to a first value that can be stored as 2 bytes, preferably an internal precision multiplier value of 0 when the size of the tile is equal to or less than 65335, and the size of the tile If the value is greater than or equal to the second value, preferably greater than 65335 but less than 653350, the internal precision multiplier value is set to 1, and the size of the tile is greater than or equal to the second value but less than or equal to the third value, preferably greater than 653350 or less than 6533500. Sets the internal precision multiplier value to 2.

In the case of more than 10 times, the internal precision multiplier is increased by one digit every 10 times.

As described above, a multiplier value and a reference coordinate value (X1, Y1) set according to the size of the tile are stored as tile header data (S104).

When the header data is determined as described above, an operation of compressing and storing coordinate values with respect to the original data stored in the database server 300 starts.

To this end, after connecting the communication unit 123 and the database server 300 online, the coordinate values (X, Y) in the tile area are read from the original data consisting of facilities and topographic maps stored in the storage unit 310. (S105).

Then, it is determined whether the relative coordinate value calculated by the subtraction of the coordinate values X and Y read out from the reference coordinate values X 1 and Y 1 is within a range that can be compressed to 2 bytes (S 106).

I.e., X1 - determines if the Y <a first value (65335) × 10 ^multiplier - X <a first value (65335) × 10 ^multiplier and the Y1.

If the relative coordinate value is in the range that can be compressed to 2 bytes in the determination of S106, the integer part of 2 bytes and the fraction part of 1 byte are respectively calculated as follows (S107).

X 'integer = (X-X1)

X 'decimal = (X-X1) decimal,

Y 'integer = (Y-Y1) integer,

Y 'decimal = (Y-Y1) decimal

However, if the relative coordinate value is not a compressible range of 2 bytes in the determination of S106, only the integer part is calculated by multiplying the read coordinate value (X, Y) by the variable 1000 (S108).

Thereafter, the data calculated as described above is compressed and stored in the storage unit 110 (S109), and it is determined whether calculation processing for all tile regions is completed (S110).

If the calculation processing for all the tile areas is not completed in the above, the process returns to step S102 to repeat the above-described steps.

When the calculation processing for all tile regions is completed, it is determined whether the processing for every layer is completed (S111), and if the processing for every layer is not completed, the process returns to the step of S102, and the processing for every layer is completed. If so, the compression operation of the geospatial data ends (S111).

As described above, the operation of the client receiving the compressed geographic information data and restoring it is as follows.

3 is a flowchart illustrating a method of restoring compressed geospatial data according to an embodiment of the present invention.

The controller 220 in the client 200 reads and sets environment setting information such as tile size and reference coordinate values X1 and Y1 for each layer for restoring compressed data from the storage 210 (S201).

Subsequently, it is determined whether a drawing inquiry is requested (S202), and when a drawing inquiry is requested, the necessary tile information is set for each layer with reference to the tile size and reference coordinate values (X1, Y1) for each layer, and then the restoration of the compressed tile for each layer is performed. The job is executed (S203).

At this time, it is checked whether the restoration information for the tile data already exists (S204), and if the restoration information exists, the restoration process is performed on the next tile linked thereto (S216).

However, if the restoration information for the tile data does not exist, the tile compression data is requested to the service server 100 connected online (S205), thereby receiving type compressed data (S206).

The tile header information of the received compressed data is analyzed to read the reference coordinate (X1, Y1) information and the internal precision multiplier information set at the time of storing (S207).

In addition, by reading the coordinate values (X, Y) included in the received compressed data, it is determined whether the data is compressed into three bytes (S209).

If it is determined that the data is compressed into 3 bytes in step S209, each coordinate value is restored from the integer part and the fractional part information (S210). If the data is compressed into 4 bytes, the compressed data is divided by 1000 and restored (S211).

In the case of the data compressed to the three bytes, each coordinate value is restored through the following operation.

X '= X1 + (X integer part × 10 ^multipliers + X fractional part / 10 ^{(2-multiplier)}

Y '= Y1 + (Y integer part × 10 ^multipliers + Y decimal part / 10 ^(2-game)

In the case of data compressed to 4 bytes, up to 3 decimal places are restored. For data compressed to 3 bytes, the internal precision multiplier is 0 for 2 decimal places, 1 for 1 decimal place, and 0 to integer part. Is restored.

The larger the tile area, the greater the internal precision multiplier and the less accurate the restored data. When the tile area is less than 65,335m, the restored data is restored to two decimal places, which increases the accuracy.

Through the above operation, the restoration process for all the tiles is completed (S212), it is determined whether the processing for all the layers is completed (S213), and if the processing for all the tiles and layers is not completed, the step of S216 When the processing for all the tiles and layers is completed, the display unit 230 displays the restored geographic information.

When applying the present invention, it is preferable to restore the compression by setting the size of the tile in a facility where the zoom in scale is large and in the case of the facility where the zoom in scale is small.

4 is an exemplary view of a storage format for compressing and storing geographic data according to an embodiment of the present invention.

As shown, the header information 410 is first stored in the tile area, and the header information includes the internal precision and the multiplier information determined according to the X, Y coordinates, which are the reference points of the tile area, and the tile area size, and the tile information. Stored records are stored.

In the case of the data 420 compressed to 3 bytes, the storage type, the number of points, the integer part of the X, Y relative coordinate values, and the fractional part are sequentially stored from the reference coordinate point of the tile area in record units.

In addition, in the case of the data 420 compressed to 4 bytes, the storage type, the number of points, and the X and Y absolute coordinates are stored in record units.

The embodiments of the present invention described above are not implemented only through the apparatus and the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. Implementation may be easily implemented by those skilled in the art from the description of the above-described embodiments.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, according to the present invention, the geographic information vector data in which the relative and absolute coordinates are mixed is provided to the client, thereby minimizing data transmission between the server and the client, thereby improving the service speed.

In addition, the effect of minimizing the distortion of data that can occur by compressing the data and at the same time maximizing the accuracy of the reconstructed data is expected.

Claims (16)

In a system for compressing geographic information data by using a relative coordinate and an absolute coordinate, A database server for storing original geographic data; And a service server that reads the original geographic information database from the database server, generates compressed data in units of tiles for each layer, and provides the service server to clients connected online. The method of claim 1, The service server may include a storage unit which stores tile size and reference coordinates for each layer for generating original geographic data as tiles, and thus compresses geographic information data in units of tiles; And a control unit for providing an online connection with the database server and the client and generating original data read from the database server into tile compressed data according to configuration data and providing the same to the client. The method of claim 2, The control unit includes a tile compression data generation unit for generating the original geographic data as compressed data in units of tiles according to the configuration data; A communication unit for online connecting the client and the database server; And a tile compressed data providing unit for providing the generated tile compressed data to a client to which the communication unit is connected. In a system for restoring compressed geospatial data mixed with relative and absolute coordinates, A storage unit configured to store configuration data for restoring data compressed on a tile basis and data restored on a tile basis; Requesting the online connected service server to transmit the compressed geospatial data in units of tiles, and restoring the compressed geospatial data received according to the configuration data including tile area size, reference coordinate value, and internal precision. Control unit; And a display unit for displaying the geographic information restored by the control unit. The method of claim 4, wherein The control unit includes a communication unit connected to the service server online; A tile compressed data request unit requesting the service server to transmit compressed data in units of tiles; A compressed data recovery unit for restoring compressed geospatial data received from the service server; And a display driver for driving the display of the restored geospatial data. In a system that compresses and transmits geographic information data by using a relative coordinate and an absolute coordinate, A database server storing original geographic information data including facility maps and topographic maps; Set the tile area, the reference coordinate value and the internal precision for reading and compressing the original geographic information database from the database server, and determine whether it can be compressed in units of tile area for each layer to use relative coordinate values and absolute coordinate values. A service server generating compressed data and providing the compressed data to a client connected online; Compressing geospatial data including a client which restores and displays the original data using tile area size, reference coordinate value, and internal precision, which are the environment setting information that was set when compressing the compressed data provided from the service server through online, and Restore system. The method of claim 6, And the service server sets the size of the tile area, the reference coordinate value, and the internal precision differently according to the displayed scale to generate the compressed data, and the client restores the compressed data. The method of claim 6, When compressing the data, the service server compresses the integer part into 2 bytes, compresses the decimal part into 1 byte, and multiplies the absolute coordinate value with a set variable for a facility that cannot compress to 2 bytes with respect to the integer part. Geospatial data compression and decompression system that compresses to 4 bytes. (a) setting the tile size and the reference coordinates (X1, Y1) according to the configuration data, setting a multiplier value according to the tile size, and storing the tile header data; (b) extracting relative coordinate values by reading absolute (X, Y) in the tile area from the original data, and determining whether the relative coordinate value is within a compressible range of 2 bytes; (c) calculating and compressing the integer part by multiplying the integer part and the fractional part respectively when the relative coordinate value is a compressible range of 2 bytes, and multiplying the variable set to the absolute coordinate value when the relative coordinate value is not compressible by 2 bytes. And; (d) repeating steps (b) and (c) to compress and store geospatial data for all tile areas and layer-specific areas. The method of claim 9, In step (a), the multiplier value according to the tile size is set to a multiplier value of 0 when the size of the tile is less than or equal to the first value that can be stored as 2 bytes, If the tile size is greater than the first value but less than the second value, the multiplier value is set to 1. And a multiplier value is set to 2 if the size of the tile is greater than or equal to the second value and less than or equal to the third value. The method of claim 9, And in the step (c), if the relative coordinate value is within a range that can be compressed to 2 bytes, the integer part is compressed to 2 bytes, and the fractional part is compressed to 1 byte to restore up to 2 decimal places upon restoration. The method of claim 9, In the step (c), if the relative coordinate value is in the range that cannot be compressed to 2 bytes, the multiplication is performed by multiplying the variable set in the absolute coordinate value to compress only the integer part into 4 bytes, and restore the geospatial data to 3 decimal places. Compression method. The method of claim 9, The data format compressed and stored in the step (c), The header information stores the internal precision and multiplier information determined according to the X and Y coordinates that are the reference points of the tile area, the tile area size, and the number of records included in the tile area. For data compressed to 3 bytes, the storage type, the number of points, the integer part of the X, Y relative coordinate values, and the fractional part are stored in order from the reference coordinate point of the tile area. Method of compressing geographic information data in which the storage type, the number of points, and the X and Y absolute coordinate values are stored in order in case of data compressed to 4 bytes. (a) reading the environmental information included in the tile size and reference coordinate value of each layer for decompressed compressed data, and waiting for a request for retrieving data; (b) setting tile information for each layer when a request for inquiry of data is detected, and reading reference coordinate values and multipliers included in header information of tile compression data received from a service server; (c) reading a coordinate value of the original data included in the received tile compressed data to determine whether the value is compressed to 3 bytes; (d) if the value is compressed to 3 bytes, the coordinate value is extracted by restoring the integer part and the fractional part information. . The method of claim 14, If the value is compressed to 3 bytes in the step (d), if the internal precision multiplier is 2, it restores to 2 decimal places, if it is 1 it restores to 1 decimal place, if it is 0 it restores to the integer part, and 4 bytes Method of restoring geospatial data if the value is compressed to 3 decimal places. In the method of compressing and restoring geospatial data using a mixture of relative and absolute coordinates, A first step of setting a tile area and a reference coordinate value for compressing original geographic data according to environment setting information, and setting an internal precision according to the tile area; A second step of generating compressed data using relative or absolute coordinates according to whether the layer can be compressed to internal precision and relative coordinates by layer of tile area of the original geographic information data; And compressing and restoring the generated compressed data for each tile area to original data according to environment setting information including tile area size, reference coordinate value, and internal precision.

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