*4.2. Second Case Study: Chedi Structure*

The results for the Chedi structure can be seen in Table 4. The RMSE horizontal for TLS was 0.069 m, and for UAV was 0.069 m. The RMSE verticals were 0.022 and 0.021 m for TLS and UAV, respectively.

**Table 4.** RMSE of Chedi, computed on 20 checkpoints for the terrestrial and UAV point cloud.


As shown in Figures 8 and 9, to evaluate the quality of positional accuracy on the pagoda façade, in this study, the selected checkpoints could be clearly seen in a field survey, such as natural features, the corner of the pagoda, and brick, and also clearly seen in UAV images and TLS data. The red line is a 2D representation obtained from the Fine Arts Department of Thailand's footprint to help assist in determining the checkpoint positions.

The reason why checkpoints are not selected at the top of the pagoda is that the edge or corner of the pagoda in the UAV and TLS point clouds cannot be clearly seen, as shown in Figures 10 and 11.

**Figure 10.** Comparison of the terrestrial and UAVs point cloud of the Prang structure: (**a**) Base of the Prang from TLS. (**b**) Top of the Prang from TLS. (**c**) Base of the Prang from UAV. (**d**) Top of the Prang from UAV.

**Figure 11.** Comparison of the terrestrial and UAVs point cloud of the Chedi structure: (**a**) Base of the Chedi from TLS. (**b**) Top of the Chedi from TLS. (**c**) Base of the Chedi from UAV. (**d**) Top of the Chedi from UAV.
