中文摘要：

为解决三角形法计算地应变中，三角形形状及其与坐标系统的关系对地应变计算精度的影响，引入条件数阈值，并讨论条件数与地应变分量计算精度之间的关系。研究结果表明：当条件数阈值设置为4．3时，地应变分量的计算精度与位移数据的精度相当。即在运用三角形法计算地应变时，将条件数阈值设置为4．3可以得到可靠的地应变分量。

英文摘要：

The main factors that affect precision of strain tensor calculation by a triangular unit are triangular shape and its orientation in the coordinate system. This paper introduces the condition number of coefficient matrix and discusses its relationship with precision of strain components. The results show that the threshold value of con- dition number for strain tensor calculation is 4.3 so as to keep that the precision of strain components and displace- ment data is in same level.