diff --git a/ShadowEditor.Web/src/gis/view/OrbitViewer.js b/ShadowEditor.Web/src/gis/view/OrbitViewer.js
index 468bfbef..304e0c28 100644
--- a/ShadowEditor.Web/src/gis/view/OrbitViewer.js
+++ b/ShadowEditor.Web/src/gis/view/OrbitViewer.js
@@ -1,4 +1,5 @@
 import Viewer from './Viewer';
+import WGS84 from '../core/WGS84';
 import MathUtils from '../utils/MathUtils';
 
 /**
@@ -12,11 +13,57 @@ function OrbitViewer(camera, domElement) {
     this.lon = 0;
     this.lat = 0;
     this.alt = MathUtils.zoomToAlt(1);
+
+    this.sphere = new THREE.Sphere(undefined, WGS84.a);
+    this.ray = new THREE.Ray();
+
+    this.isDown = false;
+    this.intersectPoint = new THREE.Vector3();
+
+    this.domElement.addEventListener('mousedown', this.onMouseDown.bind(this));
+    this.domElement.addEventListener('mousemove', this.onMouseMove.bind(this));
+    this.domElement.addEventListener('mouseup', this.onMouseUp.bind(this));
 };
 
 OrbitViewer.prototype = Object.create(Viewer.prototype);
 OrbitViewer.prototype.constructor = OrbitViewer;
 
+OrbitViewer.prototype.onMouseDown = function (event) {
+    this.isDown = true;
+    this.intersectSphere(event.offsetX, event.offsetY);
+    console.log(this.intersectPoint);
+};
+
+OrbitViewer.prototype.onMouseMove = function (event) {
+    if (!this.isDown) {
+        return;
+    }
+};
+
+OrbitViewer.prototype.onMouseUp = function (event) {
+    this.isDown = false;
+};
+
+/**
+ * 计算屏幕坐标与地球表面交点
+ * @param {*} x 屏幕坐标X
+ * @param {*} y 屏幕坐标Y
+ */
+OrbitViewer.prototype.intersectSphere = function (x, y) {
+    this.ray.origin.set(
+        x / this.domElement.clientWidth * 2 - 1,
+        -y / this.domElement.clientHeight * 2 + 1,
+        -0.00000001
+    );
+    this.ray.origin.unproject(this.camera);
+
+    this.ray.direction.set(0, 0, -1);
+    this.ray.direction.unproject(this.camera).sub(this.camera.position);
+    this.ray.direction.normalize();
+
+    this.ray.intersectSphere(this.sphere, this.intersectPoint);
+};
+
 OrbitViewer.prototype.setPosition = function (lon, lat, alt) {
     var xyz = MathUtils.lonlatToXYZ(new THREE.Vector3(lon, lat, alt));
     this.camera.position.copy(xyz);
@@ -32,6 +79,10 @@ OrbitViewer.prototype.update = function () {
 };
 
 OrbitViewer.prototype.dispose = function () {
+    this.domElement.removeEventListener('mousedown', this.onMouseDown);
+    this.domElement.removeEventListener('mousemove', this.onMouseMove);
+    this.domElement.removeEventListener('mouseup', this.onMouseUp);
+
     Viewer.prototype.dispose.call(this);
 };