let handler = new Cesium.ScreenSpaceEventHandler(viewer.scene.canvas);
handler.setInputAction(function(e){
console.log('cli',e);
//let pickId = viewer.scene.pick(e.position); //点击监听三维数据服务的实体
var cartesian=viewer.camera.pickEllipsoid(e.position,viewer.scene.globe.ellipsoid);
var cartographic=Cesium.Cartographic.fromCartesian(cartesian);
var lng=Cesium.Math.toDegrees(cartographic.longitude);//经度值
var lat=Cesium.Math.toDegrees(cartographic.latitude);//纬度值
//var mapPosition=x:lng,y:lat,z:cartographic.height;//cartographic.height的值始终为零。
console.log("longitude:" + lng + ";latitude:" + lat );
},Cesium.ScreenSpaceEventType.LEFT_CLICK);