Cesium高度解析

var viewer = new Cesium.Viewer('cesiumContainer', {

    shadows : true

});

//为true时，球体会有高程遮挡效果（在没有地形时候也会有高程遮挡效果）

viewer.scene.globe.depthTestAgainstTerrain = true;

var viewModel = {

    height: 0

};

Cesium.knockout.track(viewModel);

//获取左上角的toolbar

var toolbar = document.getElementById('toolbar');

Cesium.knockout.applyBindings(viewModel, toolbar);

//添加 3D Tiles，url是路径

var tileset = new Cesium.Cesium3DTileset({ url: Cesium.IonResource.fromAssetId(3883) });

//tileset的根已经准备就绪

tileset.readyPromise.then(function(tileset) {

    //在场景添加tileset

    viewer.scene.primitives.add(tileset);

    //zoomTo （target，offset）目标和偏移

    viewer.zoomTo(tileset, new Cesium.HeadingPitchRange(0.0, -0.5, tileset.boundingSphere.radius * 2.0));

}).otherwise(function(error) {

    //若没有加载成功，提示错误

    console.log(error);

});

Cesium.knockout.getObservable(viewModel, 'height').subscribe(function(height) {

    height = Number(height);

    if (isNaN(height)) {

        return;

        }

//地理位置

    var cartographic = Cesium.Cartographic.fromCartesian(tileset.boundingSphere.center);

    var surface = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 0.0);

    var offset = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, height);

    var translation = Cesium.Cartesian3.subtract(offset, surface, new Cesium.Cartesian3());

    tileset.modelMatrix = Cesium.Matrix4.fromTranslation(translation);

});