Export Kml

<!--
  示例：导出 KML
  说明：把场景中的实体导出成 KMZ，页面提供下载链接
  核心逻辑：exportKml({entities}) → Blob → 下载链接
  依赖：CesiumJS 1.121 · jsDelivr CDN
-->
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta name="robots" content="noindex,follow">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>导出 KML</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Widgets/widgets.css">
<style>
  html,body{height:100%;margin:0}
  body{background:#0e1116;color:#e6e8ec;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif}
  #c{height:100%}
  .tip{position:absolute;left:12px;top:12px;z-index:5;
       background:rgba(23,28,35,.9);border:1px solid #2a313b;border-radius:6px;
       padding:8px 12px;font-size:12px;color:#a2a9b6;max-width:320px;line-height:1.6}

  .dl{position:absolute;right:12px;top:12px;padding:8px 14px;border-radius:6px;
      background:#1b2530;border:1px solid #2a313b;color:#8fa3b8;font-size:12px;
      text-decoration:none}
  .dl.ready{color:#8fd3c0;border-color:#3b6355}
  .cesium-viewer-bottom .cesium-widget-credits,.cesium-viewer-animationContainer,
  .cesium-viewer-timelineContainer{display:none!important}
</style>
</head>
<body>
<div id="c"></div>
<div class="tip">导出的 KMZ 可以直接拖进 Google Earth，几何与样式都会保留。</div>
<script src="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Cesium.js"></script>
<script>
(function () {
  'use strict';

  var viewer = new Cesium.Viewer('c', {
    baseLayer: false,
    baseLayerPicker: false, geocoder: false, homeButton: false,
    sceneModePicker: false, navigationHelpButton: false,
    animation: false, timeline: false, fullscreenButton: false,
    infoBox: false, selectionIndicator: false
  });

  var scene = viewer.scene;
  scene.globe.baseColor = Cesium.Color.fromCssColorString('#1c2733');
  scene.backgroundColor = Cesium.Color.fromCssColorString('#0e1116');
  scene.skyBox.show = false;
  scene.sun.show = false;
  scene.moon.show = false;
  if (scene.skyAtmosphere) scene.skyAtmosphere.show = false;

  var lon = 116.3895, lat = 39.9035;

  viewer.entities.add({
    name: '导出面',
    polygon: {
      hierarchy: Cesium.Cartesian3.fromDegreesArray([
        116.3860, 39.9015, 116.3928, 39.9015,
        116.3928, 39.9052, 116.3860, 39.9052
      ]),
      height: 0,
      material: Cesium.Color.fromCssColorString('#4d86c8').withAlpha(0.7)
    }
  });

  viewer.entities.add({
    name: '导出路径',
    polyline: {
      positions: Cesium.Cartesian3.fromDegreesArray([
        116.3862, 39.9018, 116.3895, 39.9046, 116.3926, 39.9020
      ]),
      width: 4,
      clampToGround: true,
      material: Cesium.Color.fromCssColorString('#ffb13d')
    }
  });

  var link = document.createElement('a');
  link.className = 'dl';
  link.textContent = '下载 KMZ';
  document.body.appendChild(link);

  Cesium.exportKml({ entities: viewer.entities }).then(function (result) {
    var url = URL.createObjectURL(result.kmz);
    link.href = url;
    link.download = 'export.kmz';
    link.classList.add('ready');
  });
  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3895, 39.8970, 560),
    orientation: { heading: 0, pitch: Cesium.Math.toRadians(-46), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>