openlayers 聚合效果

 //cyd
    var cydclusterSource = new ol.source.Cluster({
      distance: 40,source: new ol.source.Vector({
        features:(new ol.format.GeoJSON()).readFeatures(JSON.stringify(cyd))
      })
    });
     //sc
     var scclusterSource = new ol.source.Cluster({
      distance: 40,source: new ol.source.Vector({
        features:(new ol.format.GeoJSON()).readFeatures(JSON.stringify(sc))
      })
    });
     //sy
     var syclusterSource = new ol.source.Cluster({
      distance: 40,source: new ol.source.Vector({
        features:(new ol.format.GeoJSON()).readFeatures(JSON.stringify(sy))
      })
    });
     //xq
     var xqclusterSource = new ol.source.Cluster({
      distance: 40,source: new ol.source.Vector({
        features:(new ol.format.GeoJSON()).readFeatures(JSON.stringify(xq))
      })
    });


 var cydstyleCache = {};
     this.cydVectorLayer = new ol.layer.Vector({
      source:cydclusterSource,style:function(feature) {     
        var size = feature.get(‘features‘).length;            
        var style = cydstyleCache[size];
        if (!style) {
          style = new ol.style.Style({
            image: new ol.style.Circle({
             radius: 20,stroke: new ol.style.stroke({
              color: ‘#fff‘
            }),fill: new ol.style.Fill({
              color: ‘#3399CC‘
            })
           }),text: new ol.style.Text({
              text: "cyd  "+size.toString(),fill: new ol.style.Fill({
                color: ‘#fff‘
              })
            })
          });
          cydstyleCache[size] = style;
        }
        return style;
      }
    });https://blog.csdn.net/zy13608089849/article/details/70809354