1. Polyline & Cesium.PolylineCollection

http://localhost:8080/Apps/Sandcastle/index.html?src=development%2FPolylines.html&label=Development

  // A simple polyline with two points.
  const polyline = polylines.add({
    
    positions: Cesium.PolylinePipeline.generateCartesianArc({
    
      positions: Cesium.Cartesian3.fromDegreesArray([
        -120.0,
        40.0,
        -110.0,
        30.0,
      ]),
    }),
    material: Cesium.Material.fromType("Color", {
    
      color: new Cesium.Color(1.0, 1.0, 1.0, 1.0),
    }),
  });

2. PolylineGeometry

http://localhost:8080/Apps/Sandcastle/gallery/development%2FPolyline.html

3. SimplePolylineGeometry

http://localhost:8080/Apps/Sandcastle/index.html?src=development%2FSimple%20Polyline.html&label=Development

特点：SimplePolylineGeometry没有width属性

4. GroundPolylineGeometry

http://localhost:8080/Apps/Sandcastle/gallery/development%2FGround%20Polyline%20Material.html

http://localhost:8080/Apps/Sandcastle/gallery/development%2FPolylines%20On%20Terrain.html

注意：必须用GroundPolylinePrimitive来创建，而不能用GroundPrimitive创建

5. 综合比较

PolylineCollection可以同时渲染多条折线，性能较高；其他类型都是单独渲染某个折线的，会导致多了的话，渲染性能受影响。