By comprehensive comparison, the improved practical weir with polygonalline is finally recommended.
综合对比分析，推荐采用改进后折线型实用堰。
2
Principles and calculation method were described of polygonalline setting and positioning of new sample plot. Application programme was appropriate for field work and could increase work efficiency.
叙述了新设样地折线测设定位方法的原理及计算方法，编制了适合于外业调查使用的计算应用程序。
3
This paper analyzed the character of sketch curve and developed the concept of principal curve of sketch curve, and provided an adaptive algorithm by polygonalline for approximating principal curve.