CN107239531B - Implementation method for expanding WMS service of GeoServer releasing custom tiles - Google Patents

Abstract

The invention discloses an implementation method for extending GeoServer to publish a custom tile WMS service, including: pre-downloading map tiles and storing them in a corresponding custom folder; establishing a configuration file of map parameter information in the custom folder ;Configure the layer corresponding to the custom folder in the data directory of GeoServer; parse out the custom tile data source information file according to the received request to obtain the network map, and locate the required custom tile data source; use the custom tile data source The tile feature class parses the map parameter information of the map tile; calls the corresponding index number calculation method according to the received map parameter information, tile slicing rules and tile naming rules, and returns the required map tiles. The invention can provide different types of custom tile data sources to the electric power business system in the form of WMS service, so as to meet the display requirements of electric power GIS for high-resolution image map data.

Description

An implementation method of extending GeoServer to publish custom tiled WMS service

technical field

The invention belongs to the technical field of intelligent power GIS, and in particular relates to an implementation method of extending GeoServer to publish custom tile WMS services, which can meet the needs of displaying multi-type, higher resolution, and updating timeliness geographic basemaps in power systems.

Background technique

With the development of power distribution and power consumption projects and the continuous input of low-voltage equipment, power GIS has put forward higher requirements for the map accuracy and detail of the project area. The Web system is developing towards a service-oriented architecture, and GIS is gradually providing services of spatial data and spatial functions in the form of services. The cost and spatial processing resources required to display higher-resolution image map data in the Web environment are greater. Mechanisms such as tiling, caching, and index optimization are required to provide power GIS services in a lightweight and service-oriented manner.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention proposes an implementation method of extending GeoServer to publish custom tile WMS services, providing different types of custom tile data sources to the power business system in the form of WMS services that follow the OGC specification, and realizing map services The loose coupling with the business system meets the display requirements of power GIS for multi-type, high-resolution image map data.

To achieve the above-mentioned technical purpose and achieve the above-mentioned technical effect, the present invention is realized through the following technical solutions:

An implementation method for extending GeoServer to publish custom tile WMS services, including the following steps:

S1: Pre-download map tiles at different scales, and store them in corresponding custom folders according to the set tile segmentation rules, tile naming rules and organization rules to form a custom tile data source;

S2: Create a configuration file in the custom folder for recording the map parameter information of the map tiles located in it;

S3: Configure the layer corresponding to the custom tile data source in the GeoServer data directory to store the custom tile data source information file;

S4: According to the received GetMap request for obtaining the network map, first use the custom tile data source information parsing class to parse the custom tile data source information file, and then use the custom tile read class to locate the custom tile that needs to be read Tile data source; finally, use the custom tile feature class to parse out the map parameter information of the map tile, and send it to the custom tile read class;

S5: The custom tile reading class calls the corresponding index number calculation method according to the received map parameter information, tile slicing rules and tile naming rules, and returns the required map tiles in response to the GetMap request for obtaining the network map.

Further, the custom tile data source is a group of map tile files with the same custom tile segmentation rule, tile naming rule and organization rule, wherein the organization rule is each map tile combination sequence.

Further, the custom tile data source information file includes: an info.xml file for defining basic description information of map tiles, a tiledata.its file for defining a storage path of map tiles, and a file for defining map tiles The tiledata.prj file for the coordinate system and projection information.

Further, the map parameter information includes: the coordinate range of the global map where the group of map tiles is located, the number of tile rows and columns corresponding to the global range under the initial scale level, the minimum and maximum scale levels, tile pixel size and extension information, so The extended information includes tile type name information, which is used to distinguish between two or more sets of map tile data of different types by using different tile type names.

Further, the network map GetMap request includes: layer name, requested geographic coordinate range, pixel size, and requested coordinate system information.

Further, the step S4 is specifically: using a custom tile data source information parsing class to read the basic description information of map tiles and the coordinate system of map tiles in the info.xml file, tiledata.its file, and tiledata.prj file And projection information, map tile storage path, the read class locates the custom tile data source that needs to be read according to the map tile storage path information; the custom tile feature class parses the corresponding custom folder The configuration file of the map parameter information, parses out the map parameter information of the map tile, and transmits it to the custom tile reading class.

Further, the step S5 is specifically as follows: the custom tile reading class invokes the corresponding index number calculation method according to the received map parameter information, custom slicing rules and tile naming rules, and obtains geographic coordinates and tile index numbers. The conversion relationship between them and the pixel resolution of the scale of tile data at all levels; the custom tile reading class requests the geographic location in the request coordinate system in the GetMap request of the network map according to the parameters in the received network map GetMap request The coordinate range is converted into the geographic coordinate range of the map tile coordinate system in the tiledata.prj file, and the theoretical tile pixel resolution is calculated according to the geographic range and geometric pixel range in the GetMap request of the network map, which is then different from the tile data. Compare the pixel resolution of the scale scale, take the closest tile data scale as the display scale, calculate the new geographic coordinate range based on the scale resolution and geometric pixel range, and use the display scale and geographic coordinate range to calculate the tile index. No. to get the tile file.

Beneficial effects of the present invention:

The invention solves the requirement of displaying geographic basemaps with higher resolution and larger data volume in the electric WebGIS, and extends the WebGIS server to support access to custom tile data in the form of WMS services by pre-cache network map tiles. Reduce the dependence on the online commercial map API, improve the display efficiency of electric power GIS, and improve the user experience of electric power GIS.

Description of drawings

Figure 1 is a framework diagram of extending GeoServer to publish custom tile WMS services;

Figure 2 is a flowchart of configuring and parsing custom map tiles, and returning to WMS to obtain map tiles required by a network map request;

FIG. 3 is a flow chart of calculating the required tile index number.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

The application principle of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in Figure 1-3, an implementation method for extending GeoServer to publish custom tile WMS services includes the following steps:

S1: Pre-download map tiles at different scales, and store them in corresponding custom folders according to the set tile segmentation rules, tile naming rules and organization rules to form a custom tile data source;

The custom tile data source is a group of map image files with the same custom tile segmentation rule, tile naming rule and organization rule, wherein the organization rule is the combination order of each map tile;

S2: Create a configuration file in the custom folder for recording the map parameter information of the map tiles located in it;

The map parameter information includes: the coordinate range of the global map where the group of map tiles is located, the number of tile rows and columns corresponding to the global range at the initial scale level, the minimum and maximum scale levels, the tile pixel size, and extension information. Including tile type name information (for example: google, worldwind), which is used to distinguish between two or more sets of map tile data of different types by using different tile type names.

S3: Configure the layer corresponding to each custom tile data source in the GeoServer data directory to store the custom tile data source information file;

The custom tile data source information file includes: an info.xml file for defining basic description information of map tiles, a tiledata.its file for defining map tile storage paths, and a map tile coordinate system for defining map tiles and The tiledata.prj file for projection information.

S4: According to the received GetMap request for obtaining the network map, first use the custom tile data source information parsing class to parse the custom tile data source information file, and then use the custom tile read class to locate the custom tile that needs to be read Tile data source; finally, use the custom tile feature class to parse out the map parameter information of the map tile, and send it to the custom tile read class;

The step S4 is specifically: using the custom tile data source information parsing class to read the basic description information of the map tiles, the coordinate system of the map tiles and the projection information in the info.xml file, the tiledata.its file and the tiledata.prj file , map tile storage path, the read class locates the custom tile data source that needs to be read according to the map tile storage path information; the map parameter information in the corresponding custom folder is parsed by the custom tile feature class configuration file, parse out the map parameter information of the map tile, and send it to the custom tile reading class;

S5: The custom tile reading class calls the corresponding index number calculation method according to the received map parameter information, tile slicing rules and tile naming rules, and returns the required map tiles in response to the GetMap request for obtaining the network map;

The step S5 is specifically as follows: the custom tile reading class invokes the corresponding index number calculation method according to the received map parameter information, the custom slicing rule and the tile naming rule, and obtains the difference between the geographic coordinates and the tile index number. Conversion relationship and pixel resolution of tile data at all scales; the custom tile reading class converts the geographic coordinate range requested in the request coordinate system in the GetMap request of the network map according to the parameters in the received network map GetMap request It is the geographic coordinate range under the map tile coordinate system in the tiledata.prj file, and calculates the theoretical tile pixel resolution according to the geographic range and geometric pixel range in the GetMap request of the network map, and then matches the tile data at all levels. Compare the pixel resolution of the scale, take the closest tile data scale as the display scale, calculate the new geographic coordinate range based on the scale resolution and geometric pixel range, and use the display scale and geographic coordinate range to calculate the tile index number , get the tile file.

The following uses Google map tiles as an example to illustrate the implementation process of the implementation method of the extended GeoServer publishing custom tile WMS service of the present invention:

The custom tile data source information parsing class, the custom tile reading class, and the custom tile feature class in this embodiment are all set in the NariImageTileSource module, where the NariImageTileSource is a custom module.

Step 1: Pre-download Google map tiles at different scales. All map tiles are stored in the TileMap folder to form a custom tile data source. In this embodiment, it is agreed that map tiles are named according to "scale level/row. No./column No. The .xml file is used to define the basic description information of map tiles, including: data name, data source and update date and other description information; the tiledata.its file is used to define the map tile storage path, and the tiledata.prj file is used to Define the map tile coordinate system and projection information. The tiledata.prj file adopts the WKT text description method of the EPSG system.

Step 2: In the TileMap folder, create a configuration file config.xml for recording the map parameter information of the map tiles located therein. The map parameter information includes: the coordinates of the global map where the group of map tiles is located Scope, the number of tile rows and columns corresponding to the global scope under the initial scale level, the minimum and maximum scale level, the pixel size of the tile, and the extension information, the extension information includes the tile type name information, which is used when two or more groups of different When using different types of map tile data, use different tile type names to distinguish them. For example, they can be named according to the segmentation rules. The tile type name of a map tile that is consistent with the WorldWind map segmentation rules is defined as "worldwind", or with a custom name.

Step 3: GeoServer receives and parses the network map GetMap request, and obtains request condition parameters, including: layer name, requested geographic coordinate range, pixel size, requested coordinate system information, etc.; when GeoServer determines that the layer to be accessed is the step When the custom tile configured in 1 is the data source, read the info.xml file, tiledata.its file and tiledata.prj file created in the coverages folder in the GeoServer data directory, and use the custom tile data source information to parse The class reads the basic description information of map tiles, the coordinate system and projection information of map tiles, and the storage path of map tiles in the info.xml file, tiledata.its file and tiledata.prj file; and then uses the custom tile to read the class according to the The map tile storage path locates the custom tile data source that needs to be read; and then parses the config.xml file under the map tile storage path information through the custom tile feature class to obtain the corresponding map parameter information. Including: the coordinate range of the global map where the group of map tiles is located, the number of tile rows and columns corresponding to the global range under the initial scale level, the minimum and maximum scale levels, the pixel size of the tile and extension information;

Step 4. The step S5 is specifically: the custom tile reading class invokes the corresponding index number calculation method according to the received map parameter information, custom slicing rules and tile naming rules, and obtains geographic coordinates and tile index numbers The conversion relationship between them and the pixel resolution of the scale of tile data at all levels; the custom tile reading class requests the geographic location in the request coordinate system in the GetMap request of the network map according to the parameters in the received network map GetMap request The coordinate range is converted into the geographic coordinate range under the map tile coordinate system in the tiledata.prj file, and the theoretical tile pixel resolution is calculated according to the geographic range and geometric pixel range in the GetMap request of the network map, and then the pixel resolution is compared with the tile. Compare the pixel resolutions of the scales at all levels of the data, take the closest tile data scale as the display scale, and calculate the new geographic coordinate range based on the scale resolution and geometric pixel range, and use the display scale and geographic coordinate range to calculate the tile scale. The tile index number to get the tile file.

For example, the configuration type information in the config.xml of the Google Map tile data source is "google", the Google Map tile segmentation rule is: the upper left corner is the starting point, and the global map range is: the value range of the x-axis is [- 20037508.3427892, 20037508.3427892], the value range of the y-axis is [-20037508.3427892, 20037508.3427892], the tiles are divided on the square projection plane, and the number of global image tiles in each layer is the level power of 4, that is, the 0th layer is 1 The first layer is 4, and the second layer is 16. In this cycle, it can be calculated that each tile has its corresponding row number and column number under each layer. When pre-downloading, customize the organization of Google tiles in the form of "EPSG900193_scale level number/row number/column number.png". The configuration type information in the config.xml of the WorldWind tile data source is "worldwind". The WorldWind tile segmentation rule is: starting from the lower left corner, and the global map range is: (-90,-180) to (90,180) , the pixel size of each tile is 512*512, the 0th layer is 10 tiles, and each next layer divides the tiles of the previous layer into four. /column number.png" to customize the organization of WorldWind tiles.

When you need to add a custom type of tile, as shown in the process in Figure 2, add a new layer and the corresponding custom tile data source configuration file in the GeoServer data directory coverages folder, in the tile data directory Deploy the newly added tile file and create the corresponding config.xml, in which the name of the custom tile type in the extended information is distinguished from the name of the existing custom tile type. In the program part, update the custom tile feature class to add a new type name to identify, add a method to calculate the custom tile segmentation and indexing rules in the custom tile read class, and customize the NariImageTileSource module in GeoServer. The calling methods of the tile data source information parsing class, the custom tile reading class, and the custom tile feature class remain unchanged, which is conducive to customizing and extending the required map tile data source.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. A realization method for expanding a WMS service of a GeoServer releasing custom tiles is characterized in that: the method comprises the following steps:

s1: pre-downloading map tiles under different scales, and storing the map tiles in corresponding custom folders according to set tile segmentation rules, tile naming rules and organization rules to form custom tile data sources;

s2: establishing a configuration file for recording map parameter information of map tiles in a custom folder;

s3: configuring a layer corresponding to a user-defined tile data source in a data directory of the GeoServer, and storing a user-defined tile data source information file;

s4: according to a received request for acquiring a network map GetMap, firstly, analyzing a self-defined tile data source information file by using a self-defined tile data source information analysis class, and then, positioning to a self-defined tile data source needing to be read by using a self-defined tile reading class; finally, map parameter information of the map tiles is analyzed by utilizing the user-defined tile feature classes and is transmitted to a user-defined tile reading class;

s5: the user-defined tile reading class calls a corresponding index number calculation method according to the received map parameter information, the tile slicing rule and the tile naming rule, responds to a request for obtaining a network map GetMap, and returns the required map tiles;

the custom tile data source information file comprises: an info.xml file for defining basic description information of the map tiles, a tiledata.its file for defining storage paths of the map tiles, and a tiledata.prj file for defining coordinate systems of the map tiles and projection information;

the step S4 specifically includes: reading map tile basic description information, a map tile coordinate system, projection information and a map tile storage path in an info.xml file, a tiledata.its file and a tiledata.prj file by using a self-defined tile data source information analysis class; the reading class locates a user-defined tile data source to be read according to the map tile storage path information; and analyzing the configuration file of the map parameter information in the corresponding custom folder by the custom tile characteristic class, analyzing the map parameter information of the map tile, and transmitting the map parameter information to the custom tile reading class.

2. The method for implementing the service of the extended GeoServer for publishing the custom tile WMS as claimed in claim 1, wherein: the custom tile data source is a group of map tile files with the same custom tile segmentation rule, tile naming rule and organization rule, wherein the organization rule is the combination sequence of each map tile.

3. The method for implementing the service of the extended GeoServer for publishing the custom tile WMS as claimed in claim 2, wherein: the map parameter information includes: the map tile set comprises a coordinate range of a global map where the map tiles are located, tile row and column numbers corresponding to the global range under an initial scale level, a minimum scale level, a maximum scale level, tile pixel sizes and expansion information, wherein the expansion information comprises tile type name information and is used for distinguishing by using different tile type names when two or more groups of map tile data of different types appear.

4. The implementation method of the extended GeoServer publishing custom tile WMS service as claimed in claim 3, wherein: the network map GetMap request comprises the following steps: layer name, requested geographical coordinate range, pixel size, requested coordinate system information.

5. The implementation method of the extended GeoServer publishing custom tile WMS service as claimed in claim 4, wherein: the step S5 specifically includes: the user-defined tile reading class calls a corresponding index number calculation method according to the received map parameter information, the user-defined slicing rule and the tile naming rule to obtain the conversion relation between the geographic coordinate and the tile index number and the pixel resolution of each level of scale of the tile data; the user-defined tile reading class converts a geographic coordinate range requested under a request coordinate system in the network map GetMap request into a geographic coordinate range under a map tile coordinate system in a tiledata.prj file according to parameters in the received network map GetMap request, calculates theoretical tile pixel resolution according to the geographic range and the geometric pixel range in the network map GetMap request, compares the theoretical tile pixel resolution with the pixel resolution of each scale of tile data, takes the closest tile data scale as a display scale, calculates a new geographic coordinate range according to the scale resolution and the geometric pixel range, and calculates a tile index number by using the display scale and the geographic coordinate range to obtain a tile file.

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