directed line

• 有向线,有向元,定向线,有向直线

directed line的用法和样例：

例句

1. The course which will cut each meridian at the same angle is termed a rhumb line.
   与每一子午线相交成同一角度的航向叫恒向线。
2. All planar structures are represented by a strike line and dip angle.
   一切平面构造均可用向线和倾斜角来表示。