cesium随笔 — 获取当前鼠标的经度、纬度、高度

代码：

function getPosition() {

        //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 height = 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);

                //获取相机高度

                height = Math.ceil(viewer.camera.positionCartographic.height);

                entity.position = cartesian;

                entity.label.show = true;

                entity.label.text = '(' + longitudeString + ', ' + latitudeString + "," + height + ')' ;

            }else {

                entity.label.show = false;

            }

        }, Cesium.ScreenSpaceEventType.MOUSE_MOVE);

        //设置鼠标滚动事件的处理函数，这里负责监听高度值变化

        handler.setInputAction(function(wheelment) {

            height = Math.ceil(viewer.camera.positionCartographic.height);

            entity.position = cartesian;

            entity.label.show = true;

            entity.label.text = '(' + longitudeString + ', ' + latitudeString + "," + height + ')' ;

        }, Cesium.ScreenSpaceEventType.WHEEL);

    }

效果：