## 3 Results
### Results of the Photogrammetric Flight  
The following elements were processed to cover the study area:  
868 photographs for Scenario A, where the GCPs were marked on a minimum of 3 and a maximum of 8 photos; 1105 photos for Scenario B, where the GCPs were marked on a minimum of 3 and a maximum of 12 photos; 968 photos for Scenario C where the GCPs were marked on a minimum of 3 and a maximum of 8 photos; and 1205 photos for Scenario D where the GCPs were marked on a minimum of 3 and a maximum of 13 photos.  
In order to evaluate the effectiveness of the rolling shutter correction model, calibration processes were performed with both compensations enabled and disabled. Table 4 presents the RMSE values for the X, Y, and Z coordinates of the CPs across the four scenarios analysed. The results demonstrate the effectiveness of the rolling shutter correction model implemented in Pix4 Dmapper. A comparison of the RMSE values across the scenarios reveals a substantial reduction in error when the rolling shutter correction is applied. For instance, in Scenario A, the RMSE decreased from 40 cm to 1.7 cm in the X direction and from 49 cm to 10.7 cm in the Z direction. Similar improvements were observed in the remaining scenarios.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Point** & \multicolumn{3}{c}{**Coordinates**} & \multicolumn{3}{c}{**Std. Deviation**} \\ \hline  & **Northing** & **Easting** & **Height** & **Northing** & **Easting** & **Height** \\ \hline  
ALHA & 4,185,231.011 & 636,738.932 & 201.797 & 0.001 & 0.001 & 0.002 \\ LRCA & 4,168,655.115 & 614,704.901 & 332.215 & 0.001 & 0.000 & 0.001 \\ MAZA & 4,162,049.758 & 649,154.772 & 55.072 & 0.000 & 0.000 & 0.001 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Coordinates of the GCPs, CPs, and the three continuous stations (ALHA, LRCA, and MAZA) for the observation period used for the adjustment using Microsoft GeoLab software (MicroSearch Corporation, Boston, MA, USA) and their standard deviations (Geodetic reference system ETRS89, UTM 30N). Values in meters.  
The single error results for the GCPs and CPs for each point in the four scenarios after applying the rolling shutter compensation are shown in Figure 4.  
The RMSE was calculated using Equation (7), through which the difference between the most accurately measured points (GNSS) and the coordinates of these same points obtained from photogrammetric adjustment was calculated.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Shutter Type** & **Scenario** & **RMSE x** & **RMSE y** & **RMSE z** \\ \hline \multirow{4}{*}{Fast Readout} & A & 40 & 33 & 49 \\  & B & 38 & 38 & 38 \\  & C & 39 & 31 & 28 \\  & D & 30 & 33 & 32 \\ \hline \multirow{4}{*}{Rolling shutter} & A & 1.7 & 4.4 & 10.7 \\  & B & 2.9 & 3.4 & 6.7 \\ \cline{1-1}  & C & 1.8 & 4.2 & 9.9 \\ \cline{1-1}  & D & 3.2 & 4.1 & 10.9 \\ \hline \end{tabular}
\end{table}
Table 4: Comparison of RMSE values for checkpoints (CPs) with and without rolling shutter compensation in Pix4 Dmapper across the four analysed scenarios. Values in centimetres.  
Figure 4: Difference between the computed GCP/Check Point 3D point and the original position in XYZ direction of the GCPs and CPs (in cm) for the four scenarios, A (pink), B (green), C (blue), and D (purple).  
After obtaining the RMSE of the GCPs and CPs separately, as in Figure 4, the RMSE was calculated for each scenario. The results are shown in Figure 5. The maximum and minimum RMSE for the GCPs were found in Scenarios B and C with the values of 2.43 cm and 1.01 cm, respectively, and for the CPs in Scenarios A and B with the values of 11.73 cm and 8.16 cm. The GSD value was the same for all of the scenarios because all the flights were scheduled at the same altitude.