有些观测站的观测线为了避开障碍物而设置成平行于主断面的折线,如淮南矿务局的李一矿等。还有些观测站为了少占用农田将观测线布设在田间道路或水渠旁,但常与主断面斜交,如新密矿务局的米村矿等。这两类观测线的特点是有一部分测点不位于主断面上,因此必须将直接观测资料换算到主断面上, Some observation stations in order to avoid obstacles and set the observation line parallel to the main section of the polyline, such as the Huai’an Mining Bureau, a mine and so on. Some observatories in order to reduce the occupation of farmland in the observation line laid in the field next to the road or canal, but often cross-section with the main section, such as the Xinmi Mine Bureau and other meters of the mine. The characteristics of these two types of observation lines are that some of the measuring points are not located on the main section, so the direct observation data must be converted to the main section,