respectively, which were the largest values among the three GCP sampling
designs. In the case of SCS GCPs spatial sampling design (Fig. 5b),
GCPs were distributed evenly in the reference image. However, they
were not dispersed sufficiently compared with the case for UKMS.
The RMSE and the mean of z were 15.59 and 243.1, respectively.
This is a 26% improvement in the criterion of the RMSE for the SRS.
Fig. 5c shows the UKMS GCPs spatial distribution after optimizing
the GCPs spatial pattern. The UKMS GCPs spatial pattern performs
the best among these three GCP sampling designs. The RMSE and
the mean of z were 14.46 and 214.2, respectively.