5.加载天地图

let tDLayer = new Cesium.WebMapTileServiceImageryProvider({
      "url": "http://{s}.tianditu.com/vec_w/wmts?service=wmts&request=GetTile&version=1.0.0&LAYER=vec&tileMatrixSet=w&TileMatrix={TileMatrix}&TileRow={TileRow}&TileCol={TileCol}&style=default&format=tiles&tk="+ getTDTTk(),
      "layer": "tDLayer",
      "style": "default",
      "format": "image/jpeg",
      "tileMatrixSetID": "GoogleMapsCompatible",
      "credit": "",
      "subdomains": ["t0","t1","t2","t3","t4","t5","t6","t7"],
      "maximumLevel": 18,
    });
    console.log(tDLayer._layer)
    this.viewer.imageryLayers.addImageryProvider(tDLayer);
    setTimeout(()=>{
      this.viewer.imageryLayers.removeAll();
      for (let i = 0; i < this.viewer.imageryLayers.length; i++) {
        let layer = this.viewer.imageryLayers.get(i)
        if(layer._layer === 'tDLayer'){
          this.viewer.imageryLayers.remove(layer);
        }
      }
    },5000)

let tdLayer = this.viewer.imageryLayers.addImageryProvider(
      new Cesium.UrlTemplateImageryProvider({
        "url": "https://{s}.tianditu.gov.cn/DataServer?T=vec_w&x={x}&y={y}&l={z}&tk=" + getTDTTk(),
        "subdomains": ["t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7"],
        "maximumLevel": 18,
      })
    );
    tdLayer.name = 'tdLayer'

    setTimeout(() => {
      // 删除方式1
      // this.viewer.imageryLayers.removeAll();

      // 删除方式2
      // this.viewer.imageryLayers.remove(tdLayer);

      // 删除方式3 循环删除
      for (let i = 0; i < this.viewer.imageryLayers.length; i++) {
        let imageryLayer = this.viewer.imageryLayers.get(i)
        if (imageryLayer['name'] === 'tdLayer') {
          // this.viewer.imageryLayers.remove(imageryLayer) // this.viewer.imageryLayers.remove(imageryLayer)  或者是 imageryLayer.show=false
          setInterval(() => {
            imageryLayer.show = !imageryLayer.show
          }, 2000)
        }
      }
    }, 5000)