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：