Extension of Ordered Information in Spatial Cube Sampling
In the field of spatial investigation,it is rare for a well-distributed sample to have units close to each other at the same time.The cube method using geographic coordinates as the equilibrium variable has the shortcoming of not capturing the spatial dependence of the total unit.In this paper,the idea of systematic sampling is innovatively introduced on the basis that cube method can capture the overall spatial trend effectively.The sampling design method proposed in this paper makes full use of the geographic coordinate information while keeping the relative position of the unit space,and gathers similar unit points to obtain the ordered population,so that the original population has a"spatial trend".First,the sampling unit ordering problem is transformed into a single source shortest path problem while maintaining the spatial correlation.Then,Dijkstra algorithm is used to obtain the ordered population,and the initial inclusion probability is updated in the flight phase of the fast cube method for ordered space sampling.Finally,through the simulation study and empirical analysis,it is shown that sorting the spatial population according to the principle of similar units being close to each other can reduce the sampling error and obtain a more balanced sample,so as to verify the feasibility of the proposed sampling idea.