The use of aerial and close-range photogrammetry in the study of dinosaur tracksites. Lower Cretaceous (upper Aptian/lower Albian) Molfetta ichnosite (Apulia, southern Italy)

Accurate mapping and three-dimensional models are crucial for studying dinosaur tracks and tracksites at different scales. The use of small Unmanned Aerial Vehicles (UAVs) for mapping and three-dimensional modelling is becoming increasingly common, allowing the capture of high-resolution images comparable to those obtained by terrestrial laser scanners and manned aerial photogrammetry, but with reduced working costs and rapid execution times. The Lower Cretaceous (upper Aptian/lower Albian) Molfetta dinosaur tracksite (Apulia, southern Italy), was used as a test area to evaluate the results of UAV based photogrammetry. We used two different drones having different technical features and for which we set different flight parameters. Ground-based photogrammetry on single footprints was also performed, in the light of the recent introduction of high-resolution digital cameras and powerful processing software, with the aim to evaluate its impact on ichnological, ichnotaxonomical, and ichnosystematic analyses. The accuracy of three-dimensional models, digital elevation models, and orthophotos generated by UAV images is extremely high and allows for rapid mapping and description of vast and/or hardly accessible tracksites with higher accuracy than that obtained from traditional field data or from digital airphotos. By coupling ground- and aerial-based photogrammetry, ichnologists can rapidly obtain consistent and affordable digital models useful to study dinosaur tracksites both at the meso- (track) and macroscale (ichnosite). The adoption of aerial and close-range photogrammetry will allow for the rapid production of data with sustainable costs that can be used both by specialists and as a means of conservation and dissemination of knowledge to the public.