A standing opaque beacon may be useful in addition . 此外，也可以使用常设的实体觇标。
2.
Permanent surveying markers as referred to in paragraph 1 of this article include wooden or steel signals and stone markers established at triangulation points , baseline points , traverse points , military control points , gravimetric points , astronomic points and leveling points of various orders and classes , as well as fixed markers used for topographic mapping , engineering surveying and deformation measurement , and installations at seabed geodetic points 第一款所称永久性测量标志，是指各等级的三角点、基线点、导线点、军用控制点、重力点、天文点、水准点的木质觇标、钢质觇标和标石标志，以及用于地形测图、工程测量和形变测量的固定标志和海底大地点设施等。
