在测定大型建筑物水平位移时,通常采用特殊的三角测量点或布置在该建筑物变形区之外的导线测量法进行前方交会测量。就一般情况而言,测点1和2之间不可见,并且角γ1和γ2不能直接测量。为了测定建筑物T_1点 In the determination of horizontal displacement of large buildings, cross-sectional measurements are usually taken using special triangulation points or wire measurements placed outside the deformation zone of the building. As a general rule, the points 1 and 2 are invisible and the angles γ1 and γ2 can not be directly measured. In order to determine the building T_1 point