World Wind Java开发之十三——加载Geoserver发布的WMS服务（转）

这篇是转载的平常心博客，原地址见：http://www.v5cn.cn/?p=171

1、WMSTiledImageLayer类说明

一个WMSTiledImageLayer类对象只能对应一个WMS发布的服务图层，使用WMS服务时需要使用到WMS元数据描述类WMSCapabilities对象，我们使用WMSCapabilites类的静态方法retrieve来获得它的对象。WMSCapabilites对象可以包含WMS服务中所以的图层和图层样式，我们通过把需要显示的图层名称保存到AVList对象中，然后通过WMSCapabilites对象和AVList来创建WMSTiledImageLayer对象。我们可以通过一个请求地址来查看WMS服务所包含的元数据。例如：http://127.0.0.1:8080/geoserver/PostGIS/wms?request=GetGapabilities&Service=WMS 问号后面的地址是固定的，可以但看如下的XML:

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<LayerqueryableLayerqueryable="1">

<Name>spearfish</Name>

<Title>spearfish</Title>

<Abstract>Layer-Group type layer: spearfish</Abstract>

<CRS>EPSG:26713</CRS>

<EX_GeographicBoundingBox>

<westBoundLongitude>-103.87791475407893</westBoundLongitude>

<eastBoundLongitude>-103.62278893469492</eastBoundLongitude>

<southBoundLatitude>44.37246687108142</southBoundLatitude>

<northBoundLatitude>44.50235105543566</northBoundLatitude>

</EX_GeographicBoundingBox>

<BoundingBoxCRSBoundingBoxCRS="EPSG:26713"minx="589425.9342365642"miny="4913959.224611808"maxx="609518.6719560538"maxy="4928082.949945881"/>

</Layer>

<LayerqueryableLayerqueryable="1">

<Name>tasmania</Name>

<Title>tasmania</Title>

<Abstract>Layer-Group type layer: tasmania</Abstract>

<CRS>EPSG:4326</CRS>

<EX_GeographicBoundingBox>

<westBoundLongitude>143.83482400000003</westBoundLongitude>

<eastBoundLongitude>148.47914100000003</eastBoundLongitude>

<southBoundLatitude>-43.648056</southBoundLatitude>

<northBoundLatitude>-39.573891</northBoundLatitude>

</EX_GeographicBoundingBox>

<BoundingBoxCRSBoundingBoxCRS="EPSG:4326"minx="-43.648056"miny="143.83482400000003"maxx="-39.573891"maxy="148.47914100000003"/>

</Layer>

<LayerqueryableLayerqueryable="1">

<Name>tiger-ny</Name>

<Title>tiger-ny</Title>

<Abstract>Layer-Group type layer: tiger-ny</Abstract>

<CRS>EPSG:4326</CRS>

<EX_GeographicBoundingBox>

<westBoundLongitude>-74.047185</westBoundLongitude>

<eastBoundLongitude>-73.907005</eastBoundLongitude>

<southBoundLatitude>40.679648</southBoundLatitude>

<northBoundLatitude>40.882078</northBoundLatitude>

</EX_GeographicBoundingBox>

<BoundingBoxCRSBoundingBoxCRS="EPSG:4326"minx="40.679648"miny="-74.047185"maxx="40.882078"maxy="-73.907005"/>

</Layer>

<LayerqueryableLayerqueryable="1">

<Name>省界_region</Name>

<Title>省界_region</Title>

<Abstract/>

<KeywordList>

<Keyword>features</Keyword>

<Keyword>省界_region</Keyword>

</KeywordList>

<CRS>EPSG:4326</CRS>

<CRS>CRS:84</CRS>

<EX_GeographicBoundingBox>

<westBoundLongitude>73.441277</westBoundLongitude>

<eastBoundLongitude>135.08693</eastBoundLongitude>

<southBoundLatitude>18.159829</southBoundLatitude>

<northBoundLatitude>53.561771</northBoundLatitude>

</EX_GeographicBoundingBox>

<BoundingBoxCRSBoundingBoxCRS="CRS:84"minx="73.441277"miny="18.159829"maxx="135.08693"maxy="53.561771"/>

<BoundingBoxCRSBoundingBoxCRS="EPSG:4326"minx="18.159829"miny="73.441277"maxx="53.561771"maxy="135.08693"/>

<Style>

<Name>polygon_x</Name>

<Title>Default Polygon</Title>

<Abstract>A sample style that draws a polygon</Abstract>

<LegendURLwidthLegendURLwidth="20"height="20">

<Format>image/png</Format>

<OnlineResourcexmlns:xlinkOnlineResourcexmlns:xlink="http://www.w3.org/1999/xlink"xlink:type="simple"xlink:href="http://localhost:8080/geoserver/cite/ows?service=WMS&request=GetLegendGraphic&format=image%2Fpng&width=20&height=20&layer=%3F%3F_region"/>

</LegendURL>

</Style>

</Layer>

里面的每一个Layer节点都是一个WMS图层。

2、例子

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package gov.nasa.worldwindx.v5cn;

import gov.nasa.worldwind.avlist.AVKey;

import gov.nasa.worldwind.avlist.AVList;

import gov.nasa.worldwind.avlist.AVListImpl;

import gov.nasa.worldwind.ogc.wms.WMSCapabilities;

import gov.nasa.worldwind.wms.WMSTiledImageLayer;

import gov.nasa.worldwindx.examples.ApplicationTemplate;

import java.net.URI;

import java.net.URISyntaxException;

public class WMSLayerTest extends ApplicationTemplate {

public static class AppFrame extends ApplicationTemplate.AppFrame{

private static final long serialVersionUID = 1L;

public AppFrame(){

try {

//请求地图的URL

String uri = "http://127.0.0.1:8080/geoserver/PostGIS/wms";

WMSCapabilities caps;

URI serverURI = new URI(uri);

//获得WMSCapabilities对象

caps = WMSCapabilities.retrieve(serverURI);

//解析WMSCapabilities数据

caps.parse();

AVList params = new AVListImpl();

//图层的名称

params.setValue(AVKey.LAYER_NAMES, "planet_osm_line");

//地图服务的协议，这里是OGC:WMS

params.setValue(AVKey.SERVICE_NAME, "OGC:WMS");

//获得地图的uri，也就是上面定义的uri

params.setValue(AVKey.GET_MAP_URL, uri);

//在本地缓存文件的名称

params.setValue(AVKey.DATA_CACHE_NAME, "planet_osm_line");

params.setValue(AVKey.TILE_URL_BUILDER, new WMSTiledImageLayer.URLBuilder(params));

WMSTiledImageLayer imageLayer = new WMSTiledImageLayer(caps,params);

//图层名称

imageLayer.setName("planet_osm_line");

imageLayer.setEnabled(true);

//图层的透明度

imageLayer.setOpacity(1);

//图层的最大显示高度

imageLayer.setMaxActiveAltitude(33500000);

getWwd().getModel().getLayers().add(imageLayer);

getLayerPanel().update(getWwd());

} catch (URISyntaxException e) {

e.printStackTrace();

} catch (Exception e) {

e.printStackTrace();

}

}

}

public static void main(String[] args) {

ApplicationTemplate.start("WMS图层", WMSLayerTest.AppFrame.class);

}

}

请求的URL就是GeoServer中点击【OpenLayers】中的路径：

图层名称就是定义发布服务是的名称，可以在GeoServer中找到。