road_point

• 定义：路网s-t坐标系中的特定位置点（point）.
• 用途：设置实体位置，用于构成pose_3d.
• 参数：参数如下表.

  表1 road_point参数

  Parameter	Type	Mandatory	Description
  road_id	string	yes	identifier for the road in which this point is located
  s	length	yes	Coordinate along the s-axis of the corresponding road
  t	length	yes	Coordinate along the t-axis of the corresponding road

keep创建

my_road: road_point with
    keep(it.road_id == '1')
    keep(it.s == 5.0m)
    keep(it.t == 0.0m)

create创建

my_point: road_point = map.create_road_point(road_id: '1', s: 5.0m, t: 0.0m)