In this paper, it is proved that the principle of level surveying is uncertainty, formula of level surveying varies with selection of horizontal surface and level surface, formula of level surveying doesn’t vary with placement of level, and the principle formula of level surveying of college surveying is explained reasonably. Finally, I advise to study all results of humans level surveying based on my paper to find some new and exciting results.

Transshipment problem is one of the basic operational research problems. In this paper, our first work is to develop a biologically inspired mathematical model for a dynamical system, which is first used to solve minimum cost flow problem. It has lower computational complexity than Physarum Solver. Second, we apply the proposed model to solve the traditional transshipment problem. Compared with the conditional methods, experiment results show the provided model is simple, effective as well as handling problem in a continuous manner.

Based on the choice characteristic of least absolute estimation ,and the principle of the minimum of summation of residual absolute value,the GM(1,1) model is proposed to distortion inspecting and forecasting.Exemples show the precision of least absolute estimation is uncertain to be higher a little than that of least squares estimation when observation value contains gross error,and the precision of least absolute estimation is lower a little than that of least squares estimation when observation value doesn’t contain gross error.So least absolute estimation isn’t beter to GM(1,1).

There are some losed datum or mistake datum when GM（1，1）model deals engineering matter,so equidistance GM(1,1) model is restricted and choosing non-equidistance GM(1,1) model is very necessary.The backgroung value functions of modeling research on non-equidistance GM(1,1) model is studied and is considered to be wrong,and strict backgroung value functions is advanced in the paper.The theory and practice approach of the strict method is introduced particularly.Feasibility and validity of this mothod is gained through surveying and mapping engineering .So, the paper has some significance of theory and practice.

.It is availability to improve GM(1,1) forecasting precision based on the combination of GM(1,1) model and linear regression.But,it is no good to deal with no-saltation points always based on linear regression,and deal with saltation points based on equidistant GM(1,1) model.So,in the paper，it has definite meaning of theory and practice to advance a new GM(1,1) combination model to solve the problem.Finally some examples are given in the paper.