OpenLayers实现地图标注聚合与动态交互示例

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
 <title></title>
 <script src="../lib/ol/ol.js"></script>
 <script type="text/javascript">
 window.onload = function () {
  //初始化地图
  var map = new ol.Map({
  target: 'map',
  layers: [
   new ol.layer.Tile({
   source: new ol.source.OSM()
   })
  ],
  view: new ol.View({
   center: new ol.proj.fromLonLat([116.28, 39.54]),
   zoom: 8
  })
  });
 
  //创建要素的数量
  //10000个点没有任何压力，50000个点稍微有些卡了，100000个点可以把浏览器卡崩溃
  var count = 10000;
  //创建一个要素数组
  var features = new Array(count);
  //坐标偏移量
  var e = 8500000;
 
  for (var i = 0; i < count; i++) {
  //要素坐标
  var coordinates = [3 * e * Math.random() - e, 2 * e * Math.random() - e];
  //新建点要素
  features[i] = new ol.Feature(new ol.geom.Point(coordinates));
  }
 
  //初始化矢量数据源
  var source = new ol.source.Vector({
  //要素
  features:features
  });
 
  //初始化聚合标注数据源
  var clusterSource = new ol.source.Cluster({
  //标注元素之间的间距
  distance: 40,
  //数据源
  source:source
  });
 
  //样式缓存
  var styleCache = {};
  //初始化矢量图层
  var clusters = new ol.layer.Vector({
  //数据源
  source: clusterSource,
  //样式
  style: function (feature, resolution) {
   //当前聚合标注数据源的要素大小
   var size = feature.get('features').length;
   //定义样式
   var style = styleCache[size];
   //如果当前样式不存在则创建
   if (!style) {
   style = [
    //初始化样式
    new ol.style.Style({
    //点样式
    image: new ol.style.Circle({
     //点的半径
     radius: 10,
     //笔触
     stroke: new ol.style.Stroke({
     color: '#fff'
     }),
     //填充
     fill: new ol.style.Fill({
     color: '#3399cc'
     })
    }),
    //文本样式
    text: new ol.style.Text({
     //文本内容
     text: size.toString(),
     //填充
     fill: new ol.style.Fill({
     color: '#fff'
     })
    })
    })
   ];
   styleCache[size] = style;
   }
   return style;
  }
  });
  //将聚合标注图层添加到map中
  map.addLayer(clusters);
 
  //获取添加聚合标注按钮
  document.getElementById('addFeatures').onclick = function () {
  //获取聚合标注数据源中的要素
  var currentFeatures = clusterSource.getSource().getFeatures();
  //如果当前数据源中没有任何要素则添加
  if (currentFeatures.length == 0) {
   clusterSource.getSource().addFeatures(features);
   clusters.setSource(clusterSource);
   map.addLayer(clusters);
  }
  };
 
  //获取移除聚合标注的按钮
  document.getElementById('removeFeatures').onclick = function () {
  //清除聚合标注数据源中的所有元素
  clusterSource.getSource().clear();
  //从map中移除聚合标注图层
  map.removeLayer(clusters);
  };
 };
 </script>
</head>
<body>
 <input type="button" name="name" value="添加聚合标签" id="addFeatures" />
 <input type="button" name="name" value="移除聚合标签" id="removeFeatures" />
 <div id="map"></div>
</body>
</html>