定海测区四等三角网布网方案的改善及其精度

原定海测区四等三角布网方案设计存在缺陷，经改进，新网图形强度明显增强，有效地控制了测量误差的累积，增加了检核条件，有助于点位精度的提高。

An improyed plan for the 4th triangulation network in Dinghal region is introduced here. After the modification, the strength of the new network is obviously increased, the accumulated error effectively controlled, the checking condition added and the point accuracy raised.