An accuracy study has been made by calculating the RMSE for digital model,
using 24 GCPs (Table 37.2) (Fig. 37.7).
RMSE ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi
P N
i¼1 Z DTM À Z REF
ð
Þ
2
n
s
ð37:1Þ
Where:
Z DTM – the points elevation from the model
Z REF – the points elevation as references
n – the number of ground control points.
Fig. 37.5 (a) Automatic generation of DTM, (b) DTM editing
Fig. 37.6 (a) DTM, (b) DSM
622
I. Vizireanu and R. Mateescu