## 5 Discussion
In Figures 19 and 20, a preliminary quantitative analysis between the geophysical and expected results in the plan is shown in terms of position and size of the detected structures, which reveal the greater or lesser capability of the used methodology for the localization and characterization of the archaeological features for the different water levels adopted in WP1 where 3D acquisitions were performed. It is evident how in wetter conditions GPR is more able for detecting the real sizes of the elements. This is clearly due to the reflection focusing effects induced by the increase of the dielectric permittivity related to the background soil. GPR results further highlight a wrong positioning of the column if compared with the planned design. The best results are obtained for those elements with regular shape, as in the cases of the rectangular tomb, paved road, and stone wall. In detail, as showed in Figure 19, the anomaly of the column in WL2 is equal to the expected sizes of 1.4 m \(\times\) 0.2 m; the reflections related to the rectangular tomb in WL1 highlight an anomaly really similar to the real one; similarly, the anomalies recorded in WL2 and WL1 for the stone wall with sizes of 1.6 m \(\times\) 1.6 m. Further, there is a strong agreement between the reflections induced by the paved road and its planimetric development. Regarding the enchytrismos, only in WL1 were the detected sizes adequately matched with the real ones. The depth of the objects, when detected, generally complies with the real ones, and some \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**WP1**} & \multicolumn{4}{c}{**WL1**} & \multicolumn{4}{c}{**WL2**} & \multicolumn{4}{c}{**WL3**} \\ \hline \multirow{2}{*}{**Buried Object**} & \multicolumn{2}{c}{**GPR**} & \multicolumn{2}{c}{**ERT**} & \multicolumn{2}{c}{**GPR**} & \multicolumn{2}{c}{**ERT**} & \multicolumn{2}{c}{**GPR**} & \multicolumn{2}{c}{**ERT**} \\ \cline{2-13}  & **Pos.** & **Size** & **Pos.** & **Size** & **Pos.** & **Size** & **Pos.** & **Size** & **Pos.** & **Size** & **Pos.** & **Size** \\ \hline Column (A) & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ \\ Rect. Tomb (B) & ✓ ✓ & ✓ ✓ & ✓ & ✗ & ✓ & ✓ & ✓ & ✓ & ✓ & ✗ & ✓ & ✓ & ✓ & ✓ \\ Paved Road (C) & ✓ & ✓ & ✓ & ✗ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ \\ Stone Wall (D) & ✓ ✓ & ✓ ✓ & ✓ & ✓ & ✓ & ✓ & ✓ & ✓ ✓ & ✓ ✓ & ✓ ✓ & ✓ ✓ & ✓ & ✓ ✓ & ✓ \\ Enchytrismos (E) & ✓ ✓ & ✓ ✓ & ✗ & ✗ & ✗ & ✗ & ✓ & ✓ & ✓ & ✓ & ✗ & ✓ & ✓ \\ Capuch. Tomb (F) & ✗ & ✗ & ✓ & ✓ & ✓ & ✓ & ✗ & ✓ ✓ & ✓ & ✓ & ✗ & ✓ ✓ & ✓ ✓ \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison between the expected and geophysical results for the detection of the buried object in terms of position and size for WL1, WL2, and WL3 in WP1. discrepancies can be related to the heterogenous compaction degree of the sand placed above the structures. Figure 17: Model co-rendered GPR and ERT loop–loop depth slices at 0.45 m (**left column**) and 0.70 m (**right column**) in WL1 (**b–e**), WL2 (**c–f**), and WL3 (**d–g**) with the site plan (**a**). Figure 19: Comparison of GPR slices at the depths of 0.25 m (a), 0.45 m (b), 0.70 m (c) and 1.00 m (d) for the different scenarios in WP1. Figure 18: Model co-rendered GPR and ERT data acquired along the two main sections (**a,b**) in WP2. Despite the lower resolution, ERTs have detected some archaeological structures and in the case of the paved road and stone wall, have permitted to characterize the sizes with high detail. This is particularly true for WL2 when the water saturation degree is in intermediate conditions. Regarding the other buried objects, it is possible to define only the position; indeed, the sizes of the resulting electrical anomalies do not allow to reconstruct the expected geometries.