Geomatics techniques for submerged heritage: A mobile app for tourism

The tourism sector is one of the major industries in Italy that has a high impact on local communities in terms of employment and economy. To show the results of a research project highlighting the use of new technology in the tourism sector, the Geomatics Laboratory of the Mediterranea University of Reggio Calabria has developed a mobile application for tourism. The case study is "Calarcheo Park", a non-accessible underwater archaeological park located in Reggio Calabria, near the remains of the old walls of the ancient city of Reggio Calabria (Reghion, dating back to about the VIII B.C.). The main aim of this paper is to describe the process to relive and re-propose the experience of a real immersion through a journey in virtual reality. Particular attention was given to the research part concerning the simplification processes of the models inserted within an app for tourism sector. The concept app includes scenarios (seabed) and objects (Castle and artefact) obtained from three-dimensional models realized through photogrammetric techniques, therefore "heavy" models in terms of space necessary to store them, recall them and possibly process them. Considering the visualization purpose, and the metric precision needed, the 3d models were reconstructed using a rapid method. To minimize the difficulties during the direct underwater survey carried out by a human operator (e.g. limited time available during the survey, accentuated inaccuracy due to human errors), the operations were carried out using an experimental ROV (Remote Operated Vehicles), widely used to explore underwater environments, equipped with cameras to perform photogrammetric acquisition in a single dive. To enhance the results and quality of the 3d model, a procedure to improve the image quality, and optimizing the processing is also described. This work therefore illustrates the possibilities of using 3D models created by geomatics techniques within virtual environments for apps for tourism purposes.