Multi-temporal integrated geomatic surveying for heritage decay monitoring: the case of the Neptune Fountain in Bologna

The analysis of three-dimensional digital datasets is becoming more and more experimented in the field of cultural heritage monitoring. With the increased collection of 3D point clouds and digital models, there is a growing demand for rapid computational classification techniques. This project entails the geomatic-based 3D surveying (combining terrestrial laser scanning and digital photogrammetry) of the Neptune Fountain, one of Bologna's most important Renaissance-period monuments, proposing also a methodology for extracting information about the presence of biological growth on the fountain. The approach of this methodology is to integrate all available information from 2013 and two surveys in different epochs of 2023, one before and the other after a restoration campaign, to analyze the biological growth presence in different years and to propose new approaches for monitoring it. The idea behind the methods here proposed, is to demonstrate how Geomatics-based digital tools can be useful also in periodical restoration analyses and management. The described procedure is based primarily on three algorithms depending on the available data, and it constitutes the initial stage for a new approach in the Neptune fountain monitoring to be further developed. This proposal can be interpreted as an advancement over current algorithms and techniques for classifying 3D data according to defined regions, hence, as supervised point clouds classification to draw out considerations about the biological decay development in selected areas.