开源三维地球GIS引擎Cesium常用功能的开发

Cesium是一个非常优秀的三维地球GIS引擎（开源且免费）。能够加载各种符合标准的地图图层，瓦片图、矢量图等都支持。支持3DMax等建模软件生成的obj文件，支持通用的GIS计算；支持DEM高程图。测试中的3D-Tiles分支还支持倾斜摄影生成的城市三维建筑群。国内许多三维GIS产品都基于Cesium进行封装（包括一些大厂）。因为工作关系，我对Cesium的一些基本GIS功能进行了研究，特此记录下来。

如上图，这是一个给市政GIS\BIM管理平台做的原型，GIS部分使用Cesium，BIM部分使用第三方商业引擎。GIS控制宏观、BIM支持微观（现在还没有什么好的引擎能做到GIS\BIM的无缝切换）。

常用功能介绍：

• 卫星\矢量地图切换

我这里使用的是天地图提供的服务，卫星地图和矢量地图分别调用不同的接口，卫星地图显示效果如上图，矢量地图显示如下图：

• 道路及基本标注

点“道路及基本标注”后，将路名等显示并加载在原先的图层上

• 加标记点

首先在地图上点击需要加点的位置，然后在弹出框内选取颜色，设置提示文字和显示内容，点击保存；可以添加多个标记。

• 绘制线段

连续点击地图两次就可以绘制线段（可绘制折线）

• 绘制圆形

支持绘制多个圆形，每个圆形随机颜色，能够显示园的半径、面积等

• 绘制多边形

连续点击地图上的点，再右键闭合，就可以绘制多边形，能够计算多边形每一边的边长、总面积等

• 保存视角、跳转视角

保存当前的视角；输入经纬度，跳转到指定位置

• 隐藏、加载模型

可以动态加载、隐藏三维模型（为了便于演示，所有的模型均放大了几百倍）；地图上的绘制功能对所有模型都有效，包含在范围内的模型会自动高亮并显示；点选模型能自动居中并提示是否跳转到BIM模型显示（BIM模型也是基于三维WebGL的）

• 搜索

可以根据输入的关键词进行搜索，使用百度或者高德的API，或者使用天地图的API，搜索后进行定位，只是百度、高德、天地图等用的是不同的坐标系，转换非常麻烦。

• 清除绘制

清除所有绘制的部分

以上功能只要再完善下，封装下就可以成为一个很不错的三维GIS项目基础平台了，附我们公司做的GIS+BIM的产品截图，使用了3D-Tiles：）

附：示例程序的js部分代码

     var bimEngine; var msgControl; var toolbar; var fileControl; var spaceControl; var domainControl; var propertyControl; var searchControl; var markControl;
     var storeyControl; var roamingControl; var bimevent;

     var viewer = new Cesium.Viewer("cesiumContainer", {
         animation: false, //是否显示动画控件
         baseLayerPicker: false, //是否显示图层选择控件
         geocoder: true, //是否显示地名查找控件
         timeline: false, //是否显示时间线控件
         sceneModePicker: true, //是否显示投影方式控件
         navigationHelpButton: false, //是否显示帮助信息控件
         infoBox: true, //是否显示点击要素之后显示的信息
         imageryProvider: new Cesium.WebMapTileServiceImageryProvider({
             url: "http://t0.tianditu.com/img_w/wmts?service=wmts&request=GetTile&version=1.0.0&LAYER=img&tileMatrixSet=w&TileMatrix={TileMatrix}&TileRow={TileRow}&TileCol={TileCol}&style=default&format=tiles",
             layer: "tdtBasicLayer",
             style: "default",
             format: "image/jpeg",
             tileMatrixSetID: "GoogleMapsCompatible",
             show: false
         })
     });
     var scene = viewer.scene;
     var pinBuilder = new Cesium.PinBuilder();

     var vecLayer = null, roadLayer = null, electricLayers = null;

     var getEnumPropertyNames = function(obj) {
         var props = [];
         for (prop in obj) {
             props.push(prop + ': ' + obj[prop]);
         }
         return props;
     }

     var models = new Array();
     models[0] = { id: 'house1', name: 'house1', url: '../SampleData/house/house1.gltf', lon: 121.41, lat: 31.22, height: 0, pid: '4e027d42-f033-4bab-87f1-e34c8860b90e' };
     models[1] = { id: 'house2', name: 'house2', url: '../SampleData/house/house2.gltf', lon: 121.42, lat: 31.21, height: 0, pid: '918dcfaa-4568-4468-ba03-e379deaa99b7' };
     models[2] = { id: 'house3', name: 'house3', url: '../SampleData/house/house3.gltf', lon: 121.43, lat: 31.20, height: 0, pid: '2071736b-0054-4041-ad34-34f2e7a975e5' };
     models[3] = { id: 'house4', name: 'house4', url: '../SampleData/house/house4.gltf', lon: 121.44, lat: 31.22, height: 0, pid: '4e027d42-f033-4bab-87f1-e34c8860b90e' };
     models[4] = { id: 'house5', name: 'house5', url: '../SampleData/house/house5.gltf', lon: 121.41, lat: 31.21, height: 0, pid: '918dcfaa-4568-4468-ba03-e379deaa99b7' };
     models[5] = { id: 'house6', name: 'house6', url: '../SampleData/house/house6.gltf', lon: 121.42, lat: 31.20, height: 0, pid: '2071736b-0054-4041-ad34-34f2e7a975e5' };
     models[6] = { id: 'house7', name: 'house7', url: '../SampleData/house/house7.gltf', lon: 121.43, lat: 31.22, height: 0, pid: '4e027d42-f033-4bab-87f1-e34c8860b90e' };
     models[7] = { id: 'house8', name: 'house8', url: '../SampleData/house/house8.gltf', lon: 121.44, lat: 31.21, height: 0, pid: '918dcfaa-4568-4468-ba03-e379deaa99b7' };
     models[8] = { id: 'house9', name: 'house9', url: '../SampleData/house/house9.gltf', lon: 121.45, lat: 31.20, height: 0, pid: '2071736b-0054-4041-ad34-34f2e7a975e5' };
     models[9] = { id: 'house10', name: 'house10', url: '../SampleData/house/house10.gltf', lon: 121.46, lat: 31.21, height: 0, pid: '918dcfaa-4568-4468-ba03-e379deaa99b7' };
     models[10] = { id: 'house11', name: 'house11', url: '../SampleData/house/house11.gltf', lon: 121.40, lat: 31.20, height: 0, pid: '4e027d42-f033-4bab-87f1-e34c8860b90e' };
     models[11] = { id: 'villa', name: 'villa', url: '../SampleData/house3/house3.gltf', lon: 121.45, lat: 31.22, height: 0, pid: '2071736b-0054-4041-ad34-34f2e7a975e5' };

     var loadedModels = [];

     var shapes = new Array();
     shapes[0] = { layer: '测试层', author: 'liu', date: '2017-06-18', ploy: [
         { name: 'A区', type: 'ploy', points: [] }
     ]};

     var tempPoints = [];
     var tempEntities = [];
     var tempPinEntities = [];
     var tempPinLon, tempPinLat;

     var handler = null;

     $(function() {

         /**初始化**/
         $("input[name='optionsRadios']").click(function() {
             if ($("input[name='optionsRadios']:eq(1)").prop("checked")) {
                 //viewer.imageryLayers.addImageryProvider(vecLayer);
                 vecLayer = viewer.imageryLayers.addImageryProvider(new Cesium.WebMapTileServiceImageryProvider({
                     url: "http://t0.tianditu.com/vec_w/wmts?service=wmts&request=GetTile&version=1.0.0&LAYER=vec&tileMatrixSet=w&TileMatrix={TileMatrix}&TileRow={TileRow}&TileCol={TileCol}&style=default&format=tiles",
                     layer: "tdtVecBasicLayer",
                     style: "default",
                     format: "image/jpeg",
                     tileMatrixSetID: "GoogleMapsCompatible",
                     show: false
                 }));
             } else if ($("input[name='optionsRadios']:eq(0)").prop("checked")) {
                 if (viewer.imageryLayers.contains(vecLayer)) {
                     viewer.imageryLayers.remove(vecLayer);
                 }
             }
         });
         //标记层
         $("#cbxPinLayer").change(function() {
             if ($("#cbxPinLayer").prop("checked")) {
                 for (var i = 0; i < tempPinEntities.length; i++) {
                     viewer.entities.add(tempPinEntities[i]);
                 }

             } else {
                 for (var i = 0; i < tempPinEntities.length; i ++) {
                     viewer.entities.remove(tempPinEntities[i]);
                 }
             }
         });
         $("#pinColor").change(function() {
             $(this).css("background-color", $(this).val());
         });

         $("#cbxRoad").click(function() {
             if ($(this).prop("checked")) {
                 roadLayer = viewer.imageryLayers.addImageryProvider(new Cesium.WebMapTileServiceImageryProvider({
                     url: "http://t0.tianditu.com/cia_w/wmts?service=wmts&request=GetTile&version=1.0.0&LAYER=cia&tileMatrixSet=w&TileMatrix={TileMatrix}&TileRow={TileRow}&TileCol={TileCol}&style=default&format=tiles",
                     layer: "tdtImgAnnoLayer",
                     style: "default",
                     format: "image/jpeg",
                     tileMatrixSetID: "GoogleMapsCompatible",
                     show: false
                 }));
             } else {
                 viewer.imageryLayers.remove(roadLayer);
             }
         });
         $("#cbxTestArc").click(function() {
             if ($(this).prop("checked")) {
                 electricLayers = viewer.imageryLayers.addImageryProvider(new Cesium.ArcGisMapServerImageryProvider({
                     url: 'https://nationalmap.gov.au/proxy/http://services.ga.gov.au/site_3/rest/services/Electricity_Infrastructure/MapServer'
                 }));
                 viewer.camera.flyTo({
                     destination: Cesium.Rectangle.fromDegrees(114.591, -45.837, 148.970, -5.730)
                 });
             } else {
                 viewer.imageryLayers.remove(electricLayers);
             }
         });
         $("#opts .btn").click(function () {
             window.setTimeout(function() {
                 if ($("input[name='opt']:eq(0)").prop("checked")) {
                     clearEffects();
                     setTips("");
                 }
                 else if ($("input[name='opt']:eq(1)").prop("checked")) {
                     clearEffects();
                     SetMode("addPin");
                     setTips("首先在地图上点击需要加点的位置，然后在弹出框内选取颜色，设置提示文字和显示内容，点击保存");
                 }
                 else if ($("input[name='opt']:eq(2)").prop("checked")) {
                     tempPoints = [];
                     for (var i = 0; i < tempEntities.length; i++) {
                         viewer.entities.remove(tempEntities[i]);
                     }
                     for (var i = 0; i < loadedModels.length; i++) {
                         if (loadedModels[i].color == Cesium.Color.SPRINGGREEN) {
                             loadedModels[i].color = {red:1,green:1, blue:1, alpha:1};
                         }
                     }
                     clearEffects();
                     setTips("绘制的图形被清除，点选页面标记可以删除标记");
                     SetMode("erase");
                 }
                 else if ($("input[name='opt']:eq(3)").prop("checked")) {
                     clearEffects();
                     SetMode("drawLine");
                     setTips("在地图上分别点击，即可绘制多个线段，点右键结束绘制");
                 }
                 else if ($("input[name='opt']:eq(4)").prop("checked")) {
                     clearEffects();
                     SetMode("drawCircle");
                     setTips("第一次点击绘制圆心，第二次点击根据和圆心的位置绘制半径");
                 }
                 else if ($("input[name='opt']:eq(5)").prop("checked")) {
                     clearEffects();
                     SetMode("drawSquare");
                     setTips("第一、二次点击绘制长方形的一个边，再次点击根据点和边的距离绘制方形");
                 }
                 else if ($("input[name='opt']:eq(6)").prop("checked")) {
                     clearEffects();
                     SetMode("drawPloy");
                     setTips("如果需要绘制多边形，在地图上使用左键逐个点选地点，右击闭合多边形");
                 }
                 else if ($("input[name='opt']:eq(7)").prop("checked")) {
                     clearEffects();
                     SetMode("pickBuilding");
                     setTips("点选建筑查看详细的三维模型");
                 }
             },100);
         });

         var homeView = {
             destination: new Cesium.Cartesian3(-2852877.756667368, 4655857.919027944, 3288673.682311567),
             orientation: {
                 direction: new Cesium.Cartesian3(0.5437275903005284, -0.8386290220423197, -0.03258329225728158),
                 up: new Cesium.Cartesian3(0.05520718287689969, -0.00299987805272847, 0.9984704140286108)
             },
             complete: function() { LoadModel(); },
         };

         setTimeout(
             function() {
                 // scene.primitives.removeAll();
                 //reset();
                 viewer.camera.flyTo(homeView);

                 //viewer.zoomTo(wyoming);
             }, 3000);

         //var modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(
         //Cesium.Cartesian3.fromDegrees(121.49, 31.22, 0.0));
         //var model = scene.primitives.add(Cesium.Model.fromGltf({
         //    url: '../SampleData/house/house1.gltf',
         //    modelMatrix: modelMatrix,
         //    scale: 20.0,
         //    name: 'SampleHouse',
         //    color: getColor('Red', 1)
         //}));

         $("#poly-show").click(function () {
             LoadModel();
         });

         $("#poly-hide").click(function () {
             HideModel();
         });

         //alert(getEnumPropertyNames(model).join('\r'));

     });

     function LoadModel() {
         for (var i = 0; i < models.length; i++) {
             var hasLoaded = false;
             for (var j = 0; j < loadedModels.length; j ++) {
                 if (models[i].id == loadedModels[j].id) {
                     hasLoaded = true;
                 }
             }
             if (!hasLoaded) {
                 var modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(
                     Cesium.Cartesian3.fromDegrees(models[i].lon, models[i].lat, models[i].height));

                 var model = scene.primitives.add(
                     Cesium.Model.fromGltf({
                         url: models[i].url,
                         modelMatrix: modelMatrix,
                         scale: 20.0,
                         name: models[i].name,
                         id: models[i].id
                     }));
                 loadedModels.push(model);
             }
         }
         //var cartesian = viewer.camera.pickEllipsoid(loadedModels[0].modelMatrix, scene.globe.ellipsoid);
         //alert(getEnumPropertyNames(cartesian).join('\r'));

     }

     function HideModel() {
         for (var i = 0; i < loadedModels.length; i++) {
             scene.primitives.remove(loadedModels[i]);
         }
         loadedModels = [];
     }

     function setTips(message, close) {
         if ("" == message) {
             $("#message").fadeOut();
         } else {
             if (close != undefined && close == true) {
                 $("#message").html(message).fadeOut();
             } else {
                 $("#message").html(message).fadeIn();
             }
         }
     }

     function clearEffects() {
         if (handler != null) {
             handler.destroy();
         }
     }

     //设置各种操作模式
     function SetMode(mode) {
         if (mode == "drawPloy")
         {
             tempPoints = [];
             handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
             handler.setInputAction(function (click) {
                 var cartesian = viewer.camera.pickEllipsoid(click.position, scene.globe.ellipsoid);
                 if (cartesian) {
                     var cartographic = Cesium.Cartographic.fromCartesian(cartesian);
                     var longitudeString = Cesium.Math.toDegrees(cartographic.longitude);
                     var latitudeString = Cesium.Math.toDegrees(cartographic.latitude);
                     tempPoints.push({ lon: longitudeString, lat: latitudeString });
                     var tempLength = tempPoints.length;
                     drawPoint(tempPoints[tempPoints.length-1]);
                     if (tempLength > 1) {
                         drawLine(tempPoints[tempPoints.length - 2], tempPoints[tempPoints.length - 1], true);
                     }
                 }
             }, Cesium.ScreenSpaceEventType.LEFT_CLICK);

             handler.setInputAction(function (click) {
                 var cartesian = viewer.camera.pickEllipsoid(click.position, scene.globe.ellipsoid);
                 if (cartesian) {
                     var tempLength = tempPoints.length;
                     if (tempLength < 3) {
                         alert('请选择3个以上的点再执行闭合操作命令');
                     } else {
                         drawLine(tempPoints[0], tempPoints[tempPoints.length - 1], true);
                         drawPoly(tempPoints);
                         highLightAssetsInArea(tempPoints);
                         alert('多边形面积' + SphericalPolygonAreaMeters(tempPoints) + '平方米');
                         tempPoints = [];
                     }

                 }
             }, Cesium.ScreenSpaceEventType.RIGHT_CLICK);
         }
         else if (mode == "pickBuilding")
         {
             handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
             handler.setInputAction(function(click) {
                 var pick = scene.pick(click.position);
                 if (Cesium.defined(pick) && Cesium.defined(pick.node) && Cesium.defined(pick.mesh)) {
                     for (var i = 0; i < models.length; i ++) {
                         if (models[i].id == pick.node._model.id) {
                             var modelName = models[i].name;
                             var modelId = models[i].id;
                             var modelBimId = models[i].pid;
                             highLigthModel(modelId);
                             viewer.camera.flyTo({
                                 destination: Cesium.Cartesian3.fromDegrees(models[i].lon, parseFloat(models[i].lat) - 0.01, 2000.0),
                                 orientation: {
                                     direction: new Cesium.Cartesian3(0.5437275903005284, -0.8386290220423197, -0.03258329225728158),
                                     up: new Cesium.Cartesian3(0.05520718287689969, -0.00299987805272847, 0.9984704140286108)
                                 },
                                 complete: function() {
                                     if (confirm("你选择的是" + modelName + "，是否查看详细模型？")) {
                                         LoadBim(modelBimId);
                                     }
                                     unHighLightModel(modelId);
                                 },
                             });
                         }
                     }
                 }
             }, Cesium.ScreenSpaceEventType.LEFT_CLICK);
         }
         else if ("addPin" == mode)
         {
             handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
             handler.setInputAction(function (click) {
                 var cartesian = viewer.camera.pickEllipsoid(click.position, scene.globe.ellipsoid);
                 if (cartesian) {
                     var cartographic = Cesium.Cartographic.fromCartesian(cartesian);
                     tempPinLon = Cesium.Math.toDegrees(cartographic.longitude);
                     tempPinLat = Cesium.Math.toDegrees(cartographic.latitude);
                     $('#addPinModal').modal('show');
                 }
             }, Cesium.ScreenSpaceEventType.LEFT_CLICK);
         }
         else if ("erase" == mode)
         {
             handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
             handler.setInputAction(function (click) {
                 var pick = scene.pick(click.position);
                 if (Cesium.defined(pick) && Cesium.defined(pick.id) && Cesium.defined(pick.id._id)) {
                     for (var i = 0; i < models.length; i++) {
                         if ( pick.id != undefined && tempPinEntities[i].id == pick.id._id) {
                             removePoint(tempPinEntities[i]);
                             tempPinEntities.splice(i, 1);
                         }
                     }
                 }
             }, Cesium.ScreenSpaceEventType.LEFT_CLICK);
         }
         else if ("drawLine" == mode)
         {
             tempPoints = [];
             handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
             handler.setInputAction(function (click) {
                 var cartesian = viewer.camera.pickEllipsoid(click.position, scene.globe.ellipsoid);
                 if (cartesian) {
                     var cartographic = Cesium.Cartographic.fromCartesian(cartesian);
                     var longitudeString = Cesium.Math.toDegrees(cartographic.longitude);
                     var latitudeString = Cesium.Math.toDegrees(cartographic.latitude);
                     tempPoints.push({ lon: longitudeString, lat: latitudeString });
                     var tempLength = tempPoints.length;
                     drawPoint(tempPoints[tempPoints.length - 1]);
                     if (tempLength > 1) {
                         drawLine(tempPoints[tempPoints.length - 2], tempPoints[tempPoints.length - 1], true);
                     }
                 }
             }, Cesium.ScreenSpaceEventType.LEFT_CLICK);
             handler.setInputAction(function (click) {
                 tempPoints = [];
             }, Cesium.ScreenSpaceEventType.RIGHT_CLICK);
         }
         else if ("drawCircle" == mode)
         {
             tempPoints = [];
             handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
             handler.setInputAction(function (click) {
                 var cartesian = viewer.camera.pickEllipsoid(click.position, scene.globe.ellipsoid);
                 if (cartesian) {
                     var cartographic = Cesium.Cartographic.fromCartesian(cartesian);
                     var longitudeString = Cesium.Math.toDegrees(cartographic.longitude);
                     var latitudeString = Cesium.Math.toDegrees(cartographic.latitude);
                     tempPoints.push({ lon: longitudeString, lat: latitudeString });
                     var tempLength = tempPoints.length;
                     if (tempLength == 1) {
                         drawPoint(tempPoints[0]);
                     }
                     else if (tempLength == 2) {
                         drawPoint(tempPoints[1]);
                         drawLine(tempPoints[0], tempPoints[1], true);
                         //算两点间距离
                         var distance = getFlatternDistance(tempPoints[0].lat, tempPoints[0].lon, tempPoints[1].lat, tempPoints[1].lon);

                         var entity =
                         viewer.
                         entities.add({
                             position: Cesium.Cartesian3.fromDegrees(tempPoints[0].lon, tempPoints[0].lat),
                             ellipse: {
                                 semiMinorAxis: distance,
                                 semiMajorAxis: distance,
                                 height: 0,
                                 material: Cesium.Color.fromRandom({ alpha: 0.8 })
                             }
                         });
                         tempEntities.push(entity);

                         //高亮圈内模型
                         for (var i = 0; i < loadedModels.length; i++) {
                             for (var j = 0; j < models.length; j++) {
                                 if (loadedModels[i].id == models[j].id && getFlatternDistance(models[j].lat, models[j].lon, tempPoints[0].lat, tempPoints[0].lon) <= distance) {
                                     loadedModels[i].color = Cesium.Color.SPRINGGREEN;
                                 }
                             }
                         }

                         //面积
                         setTimeout(function () { alert("面积是 " + Math.PI * distance * distance + "平方米") },500);

                         tempPoints = [];
                     }
                 }
             }, Cesium.ScreenSpaceEventType.LEFT_CLICK);
         }
         else if ("drawSquare" == mode) {
             tempPoints = [];
             handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
             handler.setInputAction(function (click) {
                 var cartesian = viewer.camera.pickEllipsoid(click.position, scene.globe.ellipsoid);
                 if (cartesian) {
                     var cartographic = Cesium.Cartographic.fromCartesian(cartesian);
                     var longitudeString = Cesium.Math.toDegrees(cartographic.longitude);
                     var latitudeString = Cesium.Math.toDegrees(cartographic.latitude);
                     tempPoints.push({ lon: longitudeString, lat: latitudeString });
                     var tempLength = tempPoints.length;
                     if (tempLength == 1) {
                         drawPoint(tempPoints[0]);
                     }
                     else if (tempLength == 2) {
                         //算两点间距离
                         var distance = getFlatternDistance(tempPoints[0].lat, tempPoints[0].lon, tempPoints[1].lat, tempPoints[1].lon);

                         var entity =
                         viewer.
                         entities.add({
                             position: Cesium.Cartesian3.fromDegrees(tempPoints[0].lon, tempPoints[0].lat),
                             ellipse: {
                                 semiMinorAxis: distance,
                                 semiMajorAxis: distance,
                                 height: 0,
                                 material: Cesium.Color.fromRandom({ alpha: 0.8 })
                             }
                         });
                         tempEntities.push(entity);

                         //高亮圈内模型
                         for (var i = 0; i < loadedModels.length; i++) {
                             for (var j = 0; j < models.length; j++) {
                                 if (loadedModels[i].id == models[j].id && getFlatternDistance(models[j].lat, models[j].lon, tempPoints[0].lat, tempPoints[0].lon) <= distance) {
                                     loadedModels[i].color = Cesium.Color.SPRINGGREEN;
                                 }
                             }
                         }

                         tempPoints = [];
                     }
                 }
             }, Cesium.ScreenSpaceEventType.LEFT_CLICK);
         }
     }

     function drawPoint(point) {
         var entity =
         viewer.entities.add({
             position: Cesium.Cartesian3.fromDegrees(point.lon, point.lat),
             point: {
                 pixelSize: 10,
                 color: Cesium.Color.CHARTREUSE
             }
         });
         tempEntities.push(entity);
     }

     function removePoint(entity) {
         viewer.entities.remove(entity);
     }

     function drawLine(point1, point2, showDistance) {
         var entity =
         viewer.entities.add({
             polyline: {
                 positions: [Cesium.Cartesian3.fromDegrees(point1.lon, point1.lat), Cesium.Cartesian3.fromDegrees(point2.lon, point2.lat)],
                 width: 10.0,
                 material: new Cesium.PolylineGlowMaterialProperty({
                     color: Cesium.Color.CHARTREUSE.withAlpha(.5)
                 })
             }
         });
         tempEntities.push(entity);
         if (showDistance) {
             var w = Math.abs(point1.lon - point2.lon);
             var h = Math.abs(point1.lat - point2.lat);
             var offsetV = w >= h ? 0.0005 : 0;
             var offsetH = w < h ? 0.001 : 0;
             var distance = getFlatternDistance(point1.lat, point1.lon, point2.lat, point2.lon);
             entity =
                 viewer.entities.add({
                     position: Cesium.Cartesian3.fromDegrees(((point1.lon + point2.lon) / 2) + offsetH,
                     ((point1.lat + point2.lat) / 2) + offsetV),
                     label: {
                         text: distance.toFixed(1) + 'm',
                         font: '22px Helvetica',
                         fillColor: Cesium.Color.WHITE
                     }
                 });
             tempEntities.push(entity);
         }
     }

     function drawPoly(points) {
         var pArray = [];
         for (var i = 0; i < points.length; i ++) {
             pArray.push(points[i].lon);
             pArray.push(points[i].lat);
         }
         var entity =
         viewer.entities.add({
             polygon: {
                 hierarchy: new Cesium.PolygonHierarchy(Cesium.Cartesian3.fromDegreesArray(pArray)),
                 material: Cesium.Color.CHARTREUSE.withAlpha(.5)
             }
         });
         tempEntities.push(entity);
     }

     function getColor(colorName, alpha) {
         var color = Cesium.Color[colorName.toUpperCase()];
         return Cesium.Color.fromAlpha(color, parseFloat(alpha));
     }

     //判断点是否在多边形内
     function PointInPoly(point, polyPoints) {
         for (var c = false, i = -1, l = polyPoints.length, j = l - 1; ++i < l; j = i)
             ((polyPoints[i].lat <= point.lat && point.lat < polyPoints[j].lat) || (polyPoints[j].lat <= point.lat && point.lat < polyPoints[i].lat))
             && (point.lon < (polyPoints[j].lon - polyPoints[i].lon) * (point.lat - polyPoints[i].lat) / (polyPoints[j].lat - polyPoints[i].lat) + polyPoints[i].lon)
             && (c = !c);
         return c;
     }

     //选区内模型高亮
     function highLightAssetsInArea(points) {

         for (var i = 0; i < loadedModels.length; i++) {
             for (var j = 0; j < models.length; j ++) {
                 if (loadedModels[i].id == models[j].id && PointInPoly(models[j], points)) {
                     loadedModels[i].color = Cesium.Color.SPRINGGREEN;
                 }
             }
         }
     }

     //高亮模型
     function highLigthModel(modelId) {
         for (var i = 0; i < loadedModels.length; i ++) {
             if (loadedModels[i].id == modelId) {
                 loadedModels[i].color = Cesium.Color.SPRINGGREEN;
             }
         }
     }

     //取消高亮模型
     function unHighLightModel(modelId) {
         for (var i = 0; i < loadedModels.length; i++) {
             if (loadedModels[i].id == modelId) {
                 loadedModels[i].color = {
                     red: 1,
                     green: 1,
                     blue: 1,
                     alpha: 1
                 };
             }
         }
     }

     //定位
     function goLocation() {
         $('#flyToModal').modal('hide');
         $('#flyToModal').on('hidden.bs.modal', function(e) {
             viewer.camera.flyTo({
                 destination: Cesium.Cartesian3.fromDegrees($("#jumpLon").val(), $("#jumpLat").val(), 1000.0)
             });
         });
     }

     //加点
     function addPin() {
         $('#addPinModal').modal('hide');
         var pin = viewer.entities.add({
             name: $("#pinContent").val(),
             position: Cesium.Cartesian3.fromDegrees(tempPinLon, tempPinLat),
             billboard: {
                 image: $("#pinLabel").val() == "" ? pinBuilder.fromColor(Cesium.Color[$("#pinColor").val().toUpperCase()], 48).toDataURL() :
             pinBuilder.fromText($("#pinLabel").val(), Cesium.Color[$("#pinColor").val().toUpperCase()], 64).toDataURL(),
                 verticalOrigin: Cesium.VerticalOrigin.BOTTOM
             }
         });
         tempPinEntities.push(pin);
         $("#pinLabel").val("");
         $("#pinContent").val("");
     }

     //计算两点间距离
     function getFlatternDistance(lat1, lng1, lat2, lng2) {
         var EARTH_RADIUS = 6378137.0;    //单位M
         var PI = Math.PI;

         function getRad(d) {
             return d * PI / 180.0;
         }
         var f = getRad((lat1 + lat2) / 2);
         var g = getRad((lat1 - lat2) / 2);
         var l = getRad((lng1 - lng2) / 2);

         var sg = Math.sin(g);
         var sl = Math.sin(l);
         var sf = Math.sin(f);

         var s, c, w, r, d, h1, h2;
         var a = EARTH_RADIUS;
         var fl = 1 / 298.257;

         sg = sg * sg;
         sl = sl * sl;
         sf = sf * sf;

         s = sg * (1 - sl) + (1 - sf) * sl;
         c = (1 - sg) * (1 - sl) + sf * sl;

         w = Math.atan(Math.sqrt(s / c));
         r = Math.sqrt(s * c) / w;
         d = 2 * w * a;
         h1 = (3 * r - 1) / 2 / c;
         h2 = (3 * r + 1) / 2 / s;

         return d * (1 + fl * (h1 * sf * (1 - sg) - h2 * (1 - sf) * sg));
     }

     //计算多边形面积
     var earthRadiusMeters = 6371000.0;
     var metersPerDegree = 2.0 * Math.PI * earthRadiusMeters / 360.0;
     var radiansPerDegree = Math.PI / 180.0;
     var degreesPerRadian = 180.0 / Math.PI;
     var pointArr;
     function SphericalPolygonAreaMeters(points) {
         var totalAngle = 0;
         for (var i = 0; i < points.length; i++) {
             var j = (i + 1) % points.length;
             var k = (i + 2) % points.length;
             totalAngle += Angle(points[i], points[j], points[k]);
         }
         var planarTotalAngle = (points.length - 2) * 180.0;
         var sphericalExcess = totalAngle - planarTotalAngle;
         if (sphericalExcess > 420.0) {
             totalAngle = points.length * 360.0 - totalAngle;
             sphericalExcess = totalAngle - planarTotalAngle;
         } else if (sphericalExcess > 300.0 && sphericalExcess < 420.0) {
             sphericalExcess = Math.abs(360.0 - sphericalExcess);
         }
         return sphericalExcess * radiansPerDegree * earthRadiusMeters * earthRadiusMeters;
     }

     /*角度*/
     function Angle(p1, p2, p3) {
         var bearing21 = Bearing(p2, p1);
         var bearing23 = Bearing(p2, p3);
         var angle = bearing21 - bearing23;
         if (angle < 0) {
             angle += 360;
         }
         return angle;
     }
     /*方向*/
     function Bearing(from, to) {
         var lat1 = from.lat * radiansPerDegree;
         var lon1 = from.lon * radiansPerDegree;
         var lat2 = to.lat * radiansPerDegree;
         var lon2 = to.lon * radiansPerDegree;
         var angle = -Math.atan2(Math.sin(lon1 - lon2) * Math.cos(lat2), Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1) * Math.cos(lat2) * Math.cos(lon1 - lon2));
         if (angle < 0) {
             angle += Math.PI * 2.0;
         }
         angle = angle * degreesPerRadian;
         return angle;
     }

     function LoadBim(projId) {
         //加载模型
         $('#myTabs li:eq(1) a').tab('show');

     }