请问一下您是怎么解决的，我通过鼠标事件能获取，但是我只传经纬度进去earthPosition是undefined,经纬度转成了窗口坐标 let canvasPosition=this.viewer.scene.cartesianToCanvasCoordinates(Cesium.Cartesian3.fromDegrees(101.11119, 30.0111111))

    var earthPosition = this.viewer.scene.pickPosition(canvasPosition);
    console.log(canvasPosition)
    console.log(earthPosition)
    if(Cesium.defined(earthPosition)){
      var cartographic = Cesium.Cartographic.fromCartesian(earthPosition);
      var lon_f = Cesium.Math.toDegrees(cartographic.longitude); //lon
      var lat_f = Cesium.Math.toDegrees(cartographic.latitude); //lat
      var po_hig = cartographic.height;//这个就是获取的模型上的高度
      console.log(po_hig)
    }
	这样写有什么问题吗