coordinates(param) {
            let that = this;
            viewer.entities.removeById("coordinates");//第二次定位的时候移除上次的点
            let terrainProvider = viewer.scene.terrainProvider;
            let point = Cartographic.fromDegrees(param.longitude, param.latitude);
            var promise = sampleTerrain(terrainProvider, 13, [point]);
            when(promise, function (updatedPositions) {//获取当前地形高度
                var terrainHeight = updatedPositions[0].height;
                viewer.entities.add({//创建定位点
                    id: "coordinates",
                    name: "coordinates",
                    position: Cartesian3.fromDegrees(param.longitude, param.latitude, terrainHeight),
                    billboard: {
                        image: "../MyJS/CesiumTools/img/coordinate.png",//定位的图片样式
                    },
                });
                viewer.camera.flyTo({//定位过去
                    destination: Cartesian3.fromDegrees(param.longitude, param.latitude, 1000)
                });
            });
        },