openlayer3矢量圖層文本顯示重複

Question

This is a picture which shows the number of my shops at this place, but why on my map the number 90 is repeated?. I am using a styleFunc to determine the color, the cold is something like:

function styleFunction(feature) { 
      var destCount = feature.get("destCount"); 
      var originCount = feature.get("originCount"); 
      if (typeof originCount === "undefined") { 
       originCount = 0; 
      } 
      if (typeof destCount === "undefined") { 
       destCount = 0; 
      } 
      totalPointsCount = destCount + originCount; 
      totalPointsCount = totalPointsCount.toString(); 
      return getStyle(feature.getProperties().type); 
     } 

function styleFunction(feature) { 
      var destCount = feature.get("destCount"); 
      var originCount = feature.get("originCount"); 
      if (typeof originCount === "undefined") { 
       originCount = 0; 
      } 
      if (typeof destCount === "undefined") { 
       destCount = 0; 
      } 
      totalPointsCount = destCount + originCount; 
      totalPointsCount = totalPointsCount.toString(); 
      return getStyle(feature.getProperties().type); 
     } 

代碼創建基礎層是：

fetch('data/xml/service-meta-data.xml').then(function (response) { 
     return response.text(); 
    }).then(function (text) { 
     var result = parser.read(text); 
     var options = ol.source.WMTS.optionsFromCapabilities(result, { 
      layer: 'China', 
      matrixSet: 'EPSG:3857' 
     }); 
     var baseLayer = new ol.layer.Tile({ 
      opacity: 1, 
      source: new ol.source.WMTS(options) 
     }); 
     var map = new ol.Map({ 
      layers: [ 
       baseLayer, 
       vectorLayer 
      ], 
      overlays: [infoOverlay], 
      target: 'map', 
      view: view 
     }); 
    }) 

可以忽略所有的數據處理，並專注於stylefunc，誰能告訴我爲什麼這個數字是重複的？許多thxs

Answer 1

看看這個鏈接Openlayers3 Vector labels。

開始放大時，拼貼圖層會創建重複標籤。因此，創建它時會有ImageWMS圖層。

var baseLayer = new ol.layer.Image({ 
     opacity: 1, 
     source: new ol.source.ImageWMS(options) 
    });