高效访问海量地图数据--用OpenLayers访问GeoServer发布的地图

我叫刘半仙

发布于 2018-06-11 15:10:53

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发布于 2018-06-11 15:10:53

文章被收录于专栏：我叫刘半仙

上一篇文章中，我们介绍了用GeoServer手动发布本地Shapefile地图，那么如何在谷歌地图中展示GeoServer发布好的地图呢？

大伙先来看看本文实现最终结果：

地图放大后：

一、解决Geoserver跨域问题

为了让GeoServer发布的地图能被其他服务加载。需要设置跨域。跨域问题是由浏览器的同源策略造成的，是一种安全机制。所谓同源是要域名，端口，协议均相同。比如127.0.0.1：8080端口访问127.0.0.1：8081端口的数据就会出现问题。

我们需要在tomcat\geoserver\webapps\geoserver\WEB-INF\lib目录下加入两个jar包

下载地址：https://pan.baidu.com/s/1jIbZmopK_9hyv2bo3OltiQ

打开tomcat\geoserver\webapps\geoserver\web.xml文件，找到文件中<filter>平级的位置，添加如下内容:

<filter> 
    <filter-name>CORS</filter-name> 
    <filter-class>com.thetransactioncompany.cors.CORSFilter</filter-class> 
  <init-param> 
   <param-name>cors.allowOrigin</param-name> 
      <param-value>*</param-value> 
  </init-param> 
  <init-param> 
   <param-name>cors.supportedMethods</param-name> 
      <param-value>GET, POST, HEAD, PUT, DELETE</param-value> 
  </init-param> 
  <init-param> 
   <param-name>cors.supportedHeaders</param-name> 
      <param-value>Accept, Origin, X-Requested-With, Content-Type, Last-Modified</param-value> 
  </init-param> 
  <init-param> 
      <param-name>cors.exposedHeaders</param-name> 
      <param-value>Set-Cookie</param-value> 
  </init-param> 
  <init-param> 
      <param-name>cors.supportsCredentials</param-name> 
      <param-value>true</param-value> 
  </init-param> 
</filter>

继续在web.xml中找到<filter-mapping>平级的位置，添加:

<filter-mapping> 
    <filter-name>CORS</filter-name> 
    <url-pattern>/*</url-pattern> 
</filter-mapping>

二、创建HTML并引入OpenLayers

放入到Tomcat的ROOT下，引入所需包(可以和GeoServer同一个Tomcat)

index.html内容如下：

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <meta http-equiv=Content-Type content="text/html;charset=utf-8">
    <meta http-equiv=X-UA-Compatible content="IE=edge,chrome=1">
    <title>googlemap</title>
    <link href="resource/css/ol.css" rel="stylesheet" type="text/css" />
	
<script type="text/javascript" src="resource/js/ol.js" charset="utf-8"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.4.4/proj4.js"></script>
<script src="http://epsg.io/21461-1753.js" type="text/javascript"></script>
</head>  
<body>  
    <div id="map"></div>  
</body>  
</html>
 <script type="text/javascript">  
        	var wfsVectorLayer="";
            //初始化加载中心点
        	var extent= [374501.6659553682, 4581745.5281843925,625498.3340446339,5569829.626271695];  
        	//加载google地图
            var googleMapLayer = new ol.layer.Tile({  
                source: new ol.source.XYZ({  
                  url: 'http://www.google.cn/maps/vt/pb=!1m4!1m3!1i{z}!2i{x}!3i{y}!2m3!1e0!2sm!3i380072576!3m8!2szh-CN!3scn!5e1105!12m4!1e68!2m2!1sset!2sRoadmap!4e0!5m1!1e0'
                })
            });  
        
            //加载google交通标注图
            var googleMapLayerTranffic = new ol.layer.Tile({  
                source: new ol.source.XYZ({  
                    url:'http://www.google.cn/maps/vt?lyrs=h@189&gl=cn&x={x}&y={y}&z={z}'
                })
            });  
            //new  地图对象
            var map = new ol.Map({  
                controls: ol.control.defaults().extend([
                    new ol.control.ScaleLine()
                  ]),
                layers: [
                	googleMapLayer
                	],  
                view: new ol.View({  
                    center: ol.proj.transform(ol.extent.getCenter(extent), 'EPSG:21461', 'EPSG:4326'),
                    projection: 'EPSG:4326',  
                    zoom: 11
                }),  
                target: 'map'  
            });        
          addWms();
        
          //加载geoserver发布的地图
            function addWms(){
            	wfsVectorLayer =  new ol.layer.Tile({  
                     source:new ol.source.TileWMS({  
                         url:'http://localhost:18080/geoserver/liugh/wms?service=WMS&version=1.1.0&request=GetMap&layers=liugh:liugh&styles=&bbox=121.64615683700006,40.87619799400008,131.15122178300007,46.289391897000115&width=768&height=437&srs=EPSG:4610',  
                         projection: 'EPSG:4326',
                         params:{  
                            	  'LAYERS':'gdzygldyt' ,
                            	  'VERSION':'1.1.0'
                         }
                     })
                 }); 
            	 map.addLayer(wfsVectorLayer);
				 map.addLayer(googleMapLayerTranffic);
            }
                  
</script>

加载GeoServer发布好的地图时，填入的url是点击OpenLayers的地址：