Using the framework discussed in Section 3.2, the effect of the
sampling design for selecting GCPs on the geometric correction of
actual remotely sensed imagery is further investigated here. The
RMSE statistics and the statistical inference results for z were calculated
from 50 stratified random sampled VPs as listed in Table 2. In
the case of the SRS GCPs spatial sampling design (Fig. 5a), GCPs were
distributed unevenly and not dispersedly enough in the reference
image. The RMSE and the mean of z were 20.98 and 440.0, 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.