Digital Photogrammetry Modelling Applied to Dinosaur Tracks from Cerro Del Pueblo Formation (Late Campanian), Coahuila, Mexico: An Approach to Test Its Effectiveness as a Means of Research and Preservation
José L. Gudiño Maussán*1, Felisa J. Aguilar2, and René Hernández-Rivera3
1,3Universidad Nacional Autónoma de México, Coyoacán, Ciudad de México, México
2Centro INAH Coahuila, Saitillo, Coahuila, México
In the last decade, digital modeling techniques have been shown to be very useful in the study of fossils and their preservation, especially with ichnites (tracks) that are impossible to collect or model by traditional methods, due to deposit characteristics such as size, touristic importance and conservation status. In Cerro del Pueblo Formation (FCdP), a geological unit of the late Campanian, located in the southeast Coahuila, Mexico, there is a great fossil diversity, mainly dinosaur ichnites, which unfortunately have been little studied and are in danger of destruction, due to the erosion and human activities. The goal of this project was testing the effectiveness of a new and low cost technique with no impact for the ichnites. The technique consisted of modeling by digital photogrammetry through the open access software VisualSFM, Meshlab and ParaView. For this purpose, six dinosaur tracks in six different sites (deposits) in FCdP, were recorded. Ten commercial quality cameras (5 to 10 Mp) were used to take photos in each site. At smaller sites with a fewer number of footprints (Cantera Rojas, 26m2, [4 tracks]; Depósito de la Luz, 37.5m2, ; La Rosa, 60m2,  and Las Águilas B, 70m2, ), individual shots of ichnites were taken. Also a complete photo series throughout the deposit was taken. On the other hand, the largest sites (Paso del Oso, 168m2, ; and Las Águilas A, 340m2, ) were divided into sections to simplify the photographic record. In total, 11,840 photographs were taken, 4960 were used to generate 72 three-dimensional textured polygonal mesh models for the six localities. Models from smaller sites had better quality because of their reduced size, the large number of photos taken and fewer intrusive elements (such as stones and vegetation). In contrast, models from bigger sites lost definition, especially after certain adjustments made to improve their computer processing. During this exercise, reference parameters were obtained, looking toward increasing the effectiveness in photography for photogrammetric processing. We hope in the future to improve the quality of digital models generated.