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          openlayers提供了幾十個示例,雖然每個示例都很簡單,但卻很具有代表性,值得初學者學習。
          現在我想做一個測試,包含多個圖層、縮放條、工具條、鼠標位置、彈出窗口,其中圖層分別來自geoservr
          提供的WMS和WFS服務接口。
          主要代碼如下:
          樣式定義,定義地圖大小,工具條位置和替換按鈕圖片。
          <style type="text/css">
                  #map {
                      width: 640px;
                      height: 475px;
                      border: 1px solid black;
                  }

                  .olControlPanel div {
                    display:block;
                    position: absolute;
                              top: 0px;
                              left: 190px;
                    width:  60px;
                    height: 23px;
                    margin: 5px;
                  }
                  .olControlPanel .olControlMouseDefaultsItemActive {
                    background-image: url("/openlayers/img/Pan.gif");
                  }
                  .olControlPanel .olControlMouseDefaultsItemInactive {
                    background-image: url("/openlayers/img/PanSelected.gif");
                  }
                  .olControlPanel .olControlZoomBoxItemInactive {
                    width:  60px; 
                    height: 23px;
                    position: absolute;
                              top: 0px;
                              left: 250px;
                    background-image: url("/openlayers/img/ZoomInSelected.gif");
                  }
                  .olControlPanel .olControlZoomBoxItemActive {
                    width:  60px; 
                    height: 23px;
                    position: absolute;
                              top: 0px;
                              left: 250px;
                    background-image: url("/openlayers/img/ZoomIn.gif");
                  }
                   .olControlPanel .olControlSelectFeatureItemInactive {
                    width:  60px; 
                    height: 23px;
                    position: absolute;
                              top: 0px;
                              left: 310px;
                    background-image: url("/openlayers/img/InfoSelected.gif");
                  }
                  .olControlPanel .olControlSelectFeatureItemActive {
                    width:  60px; 
                    height: 23px;
                    position: absolute;
                              top: 0px;
                              left: 310px;
                    background-image: url("/openlayers/img/Info.gif");
                  }
              </style>
          JS代碼,核心部分。
          <script src="/openlayers/OpenLayers.js"></script>
              <script type="text/javascript">
                  <!--
                  //定義全局變量
                  var map, layer, selectControl, selectedFeature;
                  //關閉彈出窗口的函數
                  function onPopupClose(evt) {
                      selectControl.unselect(selectedFeature);
                  }
                  //構造彈出窗口的函數
                  function onFeatureSelect(feature) {
                      selectedFeature = feature;
                      popup = new OpenLayers.Popup.Anchored("chicken",
                                               feature.geometry.getBounds().getCenterLonLat(),
                                               new OpenLayers.Size(250,75),
                                               "<div style='font-size:.8em'>" + feature.attributes['cq:LNAME'] +"</div>",
                                               null, true, onPopupClose);
                      feature.popup = popup;
                      map.addPopup(popup);
                  }
                  //銷毀彈出窗口的函數
                  function onFeatureUnselect(feature) {
                      map.removePopup(feature.popup);
                      feature.popup.destroy();
                      feature.popup = null;
                  }
                  //地圖和頁面加載函數
                  function init(){
                      //設置地圖縮放范圍和縮放等級,0級比例尺最小
                      map = new OpenLayers.Map( $('map'), {  maxScale: 500, minScale: 500000, numZoomLevels: 5 });
                      //加載行政區圖層,WMS柵格圖像
                      layer = new OpenLayers.Layer.WMS( "District",
                              "http://192.98.151.17:8081/geoserver/wms", {layers: 'cq:GMAP_DISTRICT'} );
                      map.addLayer(layer);
                      //加載水系圖層,WMS柵格圖像
                      layer = new OpenLayers.Layer.WMS( "Water",
                              "http://192.98.151.17:8081/geoserver/wms", {layers: 'cq:GMAP_LAKE', 'transparent': true, format: 'image/png' } );
                      map.addLayer(layer);
                      //加載單位圖層,WFS矢量數據,由openlayers在客戶端繪制,注意:數量太多會導致速度緩慢
                      layer = new OpenLayers.Layer.WFS( "Unit",
                              "http://192.98.151.17:8081/geoserver/wfs", {typename: 'cq:GPOI_GOV'},
                         { 
                                typename: 'unit',
                                featureNS: 'http://www.openplans.org/cq',
                                extractAttributes: true,
                                maxfeatures: 10,
                                textAttrToDisplay: 'lname'
                         } );
                      map.addLayer(layer);
                      //在地圖上添加按鈕和工具條
                      zb = new OpenLayers.Control.ZoomBox();
                      var panel = new OpenLayers.Control.Panel({defaultControl: zb});
                      selectControl = new OpenLayers.Control.SelectFeature(layer, {onSelect: onFeatureSelect, onUnselect: onFeatureUnselect, hover: true});
                      panel.addControls([
                          new OpenLayers.Control.MouseDefaults(), zb, selectControl
                      ]);
                      map.addControl(panel);
                    
                      map.addControl(new OpenLayers.Control.PanZoomBar({zoomWorldIcon:false}));
                      map.addControl(new OpenLayers.Control.LayerSwitcher({'ascending':false}));
                      map.addControl(new OpenLayers.Control.MousePosition());
                      //設置初始地圖的中心坐標和縮放等級
                      map.setCenter(new OpenLayers.LonLat(106.5, 29.5), 3);
                     
                  }
                  // -->
              </script>
          HTML代碼
          <body onload="init()">
              <h1>OpenLayers Test</h1>
              <div id="panel"></div>
              <div id="map"></div>
              <textarea style="display:none" id="serialize" cols="96" rows="10"/>
            </body>

          posted on 2007-11-26 10:58 天狼 閱讀(31669) 評論(15)  編輯  收藏

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