THE APPLICATION OF PHOTOGRAMMETRIC ORTHOMOSAICS FOR DOCUMENTATION OF PALAEONTOLOGICAL SITES

DÍAZ MARTÍNEZ, IGNACIO; CITTON, PAOLO; SILVINA DE VALAIS; CÓNSOLE-GONELLA, CARLOS; HEREDIA, ARTURO; RIGUETTI, FACUNDO; VILLAFAÑE, P.

Congreso; Ist Palaeontological Virtual Congress; 2018

Fieldwork is crucial in palaeontological studies. Both when the fossils are being exposed fromthe site and when they are studied in situ. Therefore, an exhaustive documentation of theseremains and their reciprocal position within the rocks are necessary for further study, includingtaphonomical, palaeoecological, and systematical analyses. For this purpose, a powerful, noninvasive methodology, based on Structure from Motion (SfM) algorithms was used to createorthomosaics and 3D reconstructions. Documentation of fossil features was performed through 2Dphotographs taken from multiple angles and with sufficient overlap and coverage. A series ofindividual photos matched up to constitute a new composite image or orthomosaic, in which thegeometric distortion was corrected and orthorectified, such that the scale was uniform. Theorthomosaic allowed a rapid and reliable documentation of the outcrops than conventionalmethods (i.e. drawings, total station). It reproduces a precise orthogonal X-Y scheme of the siteand can be used to measure true distances and surfaces. During excavations, it is advisable togenerate an orthomosaic before and after the extraction of each fossil to subsequently analyze theoverlapping information. Thus, by adding the vertical (Z) information, three-dimensional positionsof all the remains can be reconstructed during the excavation works, and quite precise 3Dtaphonomic maps can be obtained. The generation of photogrammetric orthomosaics turned out tobe an effective, rapid and cost-effective tool for checking and correcting the relative position offossils within a site, and complementing the traditional information obtained duringpalaeontological field trips.