## 5 Conclusions  
In this research, two geomatics techniques have been compared for the study of a Roman mosaic in its original location for its transfer to a restoration area or museum, and with the possibility of it being relocated in the future back to its original location. In the present study, photogrammetry based on SfM and low-cost cameras, and terrestrial scanner or TLS have been used, which are very widespread in archaeological excavations due to the high precision obtained from their results and the massive collection of point clouds. These have been compared with a more accurate method of obtaining coordinates, but that  
\begin{table}
\begin{tabular}{c c c c c c} \hline  & \(\geq\)**5 mm** & **\textless{}5 mm** & **\textless{}2 mm** & **\textless{}1 mm** & **\textless{}0.5 mm** \\ \hline GCP vs. SfM & - & - & 4.3\% & 95.6\% & 70.1\% \\ \hline GCP vs. TLS & 9.17\% & 88.5\% & 2.39\% & - & - \\ \hline \end{tabular}
\end{table}
Table 4: Absolute range of error.  
Figure 16: Accuracy analysis. (**A**) GCP vs. SfM. (**B**) GCP vs. TLS.  
is limited in terms of production or amount of information, i.e., the total station, which has, therefore, served as a control method.  
In particular, it was observed that the marble area, that of the sink, was the one area that was influenced the most in the data acquisition with TLS, obtaining points below the elevation determined by the total station, probably because the porosity of the material produced a slight delay in the reflection of the signal emitted by the scanner. It can be concluded that the SfM technique is the one that comes closest to the optimal values generated by the total station. This is not to say that TLS is not an accurate technique since its accuracy values are very close.  
In addition, the experiments performed in this study demonstrated the higher performance level and simplicity of the SfM technique with respect to TLS performance. In addition, the SfM technique is accessible to non-specialized personnel as it involves taking photographs using a certain strategy but without the need for technical preparation. The TLS technique, on the other hand, requires several stations and the measurement of control points from all stations. When equipment costs are considered alongside these factors, where the TLS technique is 40 times more expensive, but the SfM obtained 10 times more points, photogrammetry techniques with SfM presented a clear advantage over TLS for the accurate documentation of mosaics in archaeological excavations.  
However, there are constraints to the technique of photogrammetry using SfM if it is to be extended to other types of archaeological excavations, e.g., when the distance at which the photographs are taken is not close to the object. In this case, the distance would be the equivalent to the flight altitude of a photogrammetric flight. Another important limitation is when environmental lighting conditions are not suitable; here, the TSL technique is clearly better, for example, in caves or inside buildings.  
Conceptualization, F.M.-A. and C.M.-B.; methodology, A.M.P.-R.; M.J.L.-B.; R.M.-A.; J.C.M.-G.; F.M.-A. and C.M.-B.; software, C.M.-B. and A.M.P.-R.; validation, C.M.-B. and A.M.P.-R.; formal analysis, C.M.-B. and A.M.P.-R.; data curation, J.C.M.-G.; C.M.-[PERSON] and [PERSON]; writing--original draft preparation, [PERSON], [PERSON] and [PERSON]-[PERSON]; writing--review and editing, [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] and [PERSON]; supervision, [PERSON]; project administration C.M.-[PERSON] and A.M.P.-R.; funding acquisition, [PERSON] and A.M.P.-R. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors would like to thank CIAIMBITAL (University of Almeria, CeiA3) for its support.  
The authors declare no conflict of interest.