1.实现效果

2.实现方法

实现代码如下：

 // 获取当前地图中心的经纬度
 function getCenterPosition(viewer) {
     let centerResult = viewer.camera.pickEllipsoid(
         new Cesium.Cartesian2(
             viewer.canvas.clientWidth / 2,
             viewer.canvas.clientHeight / 2,
         ),
     )
     let curPosition = Cesium.Ellipsoid.WGS84.cartesianToCartographic(centerResult);
     let curLongitude = (curPosition.longitude * 180) / Math.PI;
     let curLatitude = (curPosition.latitude * 180) / Math.PI;
     return {
         lon: curLongitude,
         lat: curLatitude,
     }