This section shows the flow chart of three sampling stages, the second stage of field investigations is not here. The third stage of overall estimates and inference can be divided into two types: with sample site and without sample site, the actual operation flow chart is as follows:

Figure 1: The first stage of sampling

 

Figure 2： The third stage of sampling (to distribute sample sites)

 

Figure 3： The third stage of sampling (to distribute sample sites)