 let layer = new DC.TilesetLayer('layer')
      viewer.addLayer(layer)
      let tileset = new DC.Tileset(
        '//resource.dvgis.cn/data/3dtiles/dayanta/tileset.json'
      )
      tileset.setHeight(-430)
      layer.addOverlay(tileset)
      let tc = new DC.TrackController(viewer)
      let positions =
        '108.95672281090324,34.21936342653068;108.96190926401181,34.21960987901689'
      let track = new DC.Track(positions, 20, () => {}, {
        clampToTileset: true,
      })
      track.setModel('