Figure 13

Variation function cloud map of each stratum in which each point represents a data pair, the abscissa represents the distance between the two points, and the ordinate represents the variation function value. The first layer and the second layer show that as the distance of the sample points increases, the value of the variation function increases gradually, and the point cloud increases gradually, which accords with the characteristics of spatial autocorrelation. The cloud images of the other four strata are scattered and have no obvious trend, indicating that they do not have the property of spatial autocorrelation.