// 通过经纬度获取高程

function getheightbylonlat(lon,lat){

  var terrainProvider = Cesium.createWorldTerrain();

  var positions = [

    Cesium.Cartographic.fromDegrees(lon,lat)

  ];

  // var promise = new Cesium.sampleTerrain(this.viewer.terrainProvider)

  var promise = new Cesium.sampleTerrainMostDetailed(terrainProvider,positions);

  Cesium.when(promise,function(updatedPositions){

    console.log(positions[0].height);

    // console.log("updatedPositions"+updatedPositions);

  })

}

// 读取经纬度

  this.$http

        .get("./public/jwd.json")

        .then((response) => {

          var data = response.data;

          data.forEach(element => {

            getheightbylonlat(element.a,element.b);

            // console.log(element.a+","+element.b);

          });

        })