Cesium获取鼠标点击位置（PickPosition）  

Cesium获取当前点击位置坐标

sandcastle环境示例

第一步：创建范围矩形,其中west, south, east, north是以度为单位

var rectangle = new Cesium.Rectangle.fromDegrees(west, south, east, north);

第二步：相机定位

viewer.camera.flyTo({

 destination: rectangle

});

 坐标转换

var cartographic = Cesium.Cartographic.fromCartesian(cartesian); //根据笛卡尔坐标获取到弧度
var lng = Cesium.Math.toDegrees(cartographic.longitude); //根据弧度获取到经度
var lat = Cesium.Math.toDegrees(cartographic.latitude); //根据弧度获取到纬度

var viewer = new Cesium.Viewer('cesiumContainer');
var scene = viewer.scene;
var clock = viewer.clock;
var referenceFramePrimitive;
function viewRectangle() {
    Sandcastle.declare(viewRectangle);
    var west = -77.0;
    var south = 38.0;
    var east = -72.0;
    var north = 42.0;
    var rectangle = Cesium.Rectangle.fromDegrees(west, south, east, north);
    viewer.camera.setView({
        destination: rectangle
    });
    // Show the rectangle.  Not required; just for show.
    viewer.entities.add({
        rectangle : {
            coordinates : rectangle,
            fill : false,
            outline : true,
            outlineColor : Cesium.Color.WHITE
        }
    });
}
function flyToRectangle() {
    Sandcastle.declare(flyToRectangle);
//得到当前三维场景
        var scene = viewer.scene;
        //得到当前三维场景的椭球体
        var ellipsoid = scene.globe.ellipsoid;
        var entity = viewer.entities.add({
            label : {
                show : false
            }
        });
        var longitudeString = null;
        var latitudeString = null;
        var cartesian = null;
        // 定义当前场景的画布元素的事件处理
        var handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
        //设置鼠标移动事件的处理函数，这里负责监听x,y坐标值变化
        handler.setInputAction(function(movement) {
            //通过指定的椭球或者地图对应的坐标系，将鼠标的二维坐标转换为对应椭球体三维坐标
            cartesian = viewer.camera.pickEllipsoid(movement.endPosition, ellipsoid);
            if (cartesian) {
                //将笛卡尔坐标转换为地理坐标
                var cartographic = ellipsoid.cartesianToCartographic(cartesian);
                //将弧度转为度的十进制度表示
                longitudeString = Cesium.Math.toDegrees(cartographic.longitude);
                latitudeString = Cesium.Math.toDegrees(cartographic.latitude);
                entity.position = cartesian;
                entity.label.show = true;
                entity.label.text = '(' + longitudeString + ', ' + latitudeString + ')' ;
            }else {
                entity.label.show = false;
            }
        }, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
    var west = -90.0;
    var south = 40.1;
    var east = -87.0;
    var north = 40.2;
    var rectangle = Cesium.Rectangle.fromDegrees(west, south, east, north);
    viewer.camera.flyTo({
        destination : rectangle
    });
    // Show the rectangle.  Not required; just for show.
    viewer.entities.add({
        rectangle : {
            coordinates : rectangle,
            fill : false,
            outline : true,
            outlineColor : Cesium.Color.WHITE
        }
    });
}
var viewChanged = document.getElementById('viewChanged');
var removeStart;
var removeEnd;

Sandcastle.addToolbarMenu([{
    text : 'Fly to Rectangle',
    onselect : function() {
        flyToRectangle();
        Sandcastle.highlight(flyToRectangle);
    }
}, {
    text : 'View a Rectangle',
    onselect : function() {
        viewRectangle();
        Sandcastle.highlight(viewRectangle);
    }
}
]);
scene.morphComplete.addEventListener(function() {
    Sandcastle.reset();
});