A description of a polyline on terrain or 3D Tiles. Only to be used with 
    
GroundPolylinePrimitive.
| 参数名称 | 类型 | 描述信息 | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| options | object | Options with the following properties: 
 | 
Throws:
- 
    DeveloperError : At least two positions are required.
使用示例:
const positions = Cesium.Cartesian3.fromDegreesArray([
  -112.1340164450331, 36.05494287836128,
  -112.08821010582645, 36.097804071380715,
  -112.13296079730024, 36.168769146801104
]);
const geometry = new Cesium.GroundPolylineGeometry({
  positions : positions
});参考:
成员(属性)
    The type of path the polyline must follow. Valid options are 
ArcType.GEODESIC and ArcType.RHUMB.
- 
    
    
    
    
    
    
    
    
    默认值:
    
ArcType.GEODESIC
    
    
    
    
    
    
    
    The distance interval used for interpolating options.points. Zero indicates no interpolation.
Default of 9999.0 allows centimeter accuracy with 32 bit floating point.
- 
    
    
    
    
    
    
    
    
    默认值:
    
9999.0
    
    
    
    
    
    
    
    Whether during geometry creation a line segment will be added between the last and first line positions to make this Polyline a loop.
If the geometry has two positions this parameter will be ignored.
- 
    
    
    
    
    
    
    
    
    默认值:
    
false
    
    
    
    
    
    
    
    The screen space width in pixels.
方法
    Stores the provided instance into the provided array.
    
| 参数名称 | 类型 | 默认值 | 描述信息 | 
|---|---|---|---|
| value | PolygonGeometry | The value to pack. | |
| array | Array.<number> | The array to pack into. | |
| startingIndex | number | 0 | 可选 The index into the array at which to start packing the elements. | 
返回值:
    The array that was packed into
    
    Retrieves an instance from a packed array.
    
| 参数名称 | 类型 | 默认值 | 描述信息 | 
|---|---|---|---|
| array | Array.<number> | The packed array. | |
| startingIndex | number | 0 | 可选 The starting index of the element to be unpacked. | 
| result | PolygonGeometry | 可选 The object into which to store the result. | 
