（一）、Cesium 简单使用
使用在线资源
- 新建html文件
- 引入js文件
- 编写代码
例子：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<!-- Include the CesiumJS JavaScript and CSS files -->
<!--Cesium js文件引入 -->
<script src="https://cesium.com/downloads/cesiumjs/releases/1.83/Build/Cesium/Cesium.js"></script>
<link href="https://cesium.com/downloads/cesiumjs/releases/1.83/Build/Cesium/Widgets/widgets.css" rel="stylesheet">
</head>
<body>
<!-- 视图显示容器 -->
<div id="cesiumContainer"></div>
<script>
// 注册密钥: https://cesium.com/ion/tokens.
// 账号密钥
Cesium.Ion.defaultAccessToken = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJqdGkiOiI5YjdiMzE0OC04OGE5LTQ4NGEtODZkMC1kN2U1MmMyMWYwNzIiLCJpZCI6MTYwNjUsInNjb3BlcyI6WyJsZ24iLCJwciIsImFjdyIsImFzbCIsImFzciIsImFzdyIsImFzcyIsImdjIiwibHIiLCJsdyIsInRyIiwidHciLCJ1c2ciXSwiaWF0IjoxNjI2OTYwOTM1LCJleHAiOjE2Mjc1NjU3MzV9.VcNEmfaN_fYKeuLt7mXXQg77v-SRIIP7Cy-ZsgPuj5I';
// 初始化容器 （容器：`cesiumContainer` ）
const viewer = new Cesium.Viewer('cesiumContainer', {
terrainProvider: Cesium.createWorldTerrain()
});
// 添加资源
const buildingTileset = viewer.scene.primitives.add(Cesium.createOsmBuildings());
// 视图缩放至加载资源位置
viewer.camera.flyTo({
destination : Cesium.Cartesian3.fromDegrees(-122.4175, 37.655, 400),
orientation : {
heading : Cesium.Math.toRadians(0.0),
pitch : Cesium.Math.toRadians(-15.0),
}
});
</script>
</div>
</body>
</html>