###### Abstract  
The discovery of a Roman mosaic from the 2 nd century AD in Cantillana (Seville) generated interest and the need for exhaustive documentation, so that it could be recreated with real measurements in a 3D model, not only to obtain an exact replica, but with the intention of analyzing and studying the behavior of two main geomatics techniques. Thus, the objective of this study was the comparative analysis of both techniques: near object photogrammetry by SfM and terrestrial laser scanner or TLS. The aim of this comparison was to assess the use of both techniques in archaeological excavations. Special attention was paid to the accuracy and precision of measurements and models, especially in altimetry. Mosaics are frequently relocated from their original location to be exhibited in museums or for restoration work, after which they are returned to their original place. Therefore, the altimetric situation is of special relevance. To analyze the accuracy and errors of each technique, a total station was used to establish the real values of the ground control points (GCP) on which the comparisons of both methods were to be made. It can be concluded that the SfM technique was the most accurate and least limiting for use in semi-burried archaeological excavations. This manuscript opens new perspectives for the use of SfM-based photogrammetry in archaeological excavations. archaeology; photogrammetry; SfM; scanner; TLS; mosaic; marble +
Footnote †: journal: Medicaltheoretical accuracy. In summary, current TLS systems usually have a high millimeter spatial resolution, with an observation distance of tens of meters from the station, and the standard error is usually \(\pm\)2 mm at 25 m [8]. The first manuscript on the application of TLS for archaeology was fairly recent, according to the Scopus database, and dates from 2007 [9], where its possible use was suggested, but no archaeological work was performed. Later, in 2008, it was applied in an archaeological excavation in Egypt, and the results were combined with aerial photogrammetry [10]. These applications are slowly starting to be used, as is shown in the related literature. One application in 2009 [11] related to point cloud modeling, and demonstrated that it is a complex task to extract its unstructured information, requiring powerful software tools. In the 2010s, TLS was mostly used for archaeological applications in caves, such as in the Upper Paleolithic cave of Parpallo in Gandia [12], or in the Bronze Age cave \"les fraux\", in Perigord (France) [13]. Regarding the comparison between both methods, it is worth mentioning studies carried out in 2002 comparing TLS and SfM photogrammetry, usually in optimal conditions for the recording of cultural heritage, and that both methods obtained similar results [14]. Only in 2012 was TLS compared with terrestrial photogrammetry in archaeological applications [15], in particular with measurements made on a part of the Palace of Phasistos on the island of Crete. In this case, results showed that in the recording of the data set, there were average differences of the order of a few centimeters, highlighting the superior ability of TLS applied on surfaces to describe the undulating portions of the walls of that settlement. On the other hand, recent studies have shown the advantage of SfM over TLS in the study of archaeological sites on surfaces such as petroglyphs [16]. A study comparing TLS with SfM for the evaluation of bulk densities of bulk samples [17] showed the validity of both methods with a less than 4.5% variation, but the authors of the study do not recommend either of the two methods. However, in recent modeling applications for building structures, a comparison between the two techniques has been performed on the ruins of the Church of the Annunciation of the Blessed Virgin Mary on Mount Carmel in Zagorz (Poland) [18].