Three-Dimensional Documentation and Virtual Web Navigation System for the Indoor and Outdoor Exploration of a Complex Cultural Heritage Site

The spread of new survey strategies for the documentation and 3D reconstruction of complex cultural heritage sites enables the implementation of virtual web navigation systems that are useful for their virtual fruition. In particular, remote indoor/outdoor exploration enhances our knowledge of cultural heritage sites, even in inaccessible or difficult-to-visit states. However, the 3D data acquisition of complex sites for documentation remains a challenge, and the 3D virtual exploration of these datasets is often limited to property software implementations. This work describes the 3D documentation and construction of an indoor/outdoor web visualization system based on the WebGL open-source technology of a complex cultural heritage site. The case study regards the complex of "Santa Maria della Grotta" in Marsala (Italy), which is composed of a church that is located mostly underground and is connected to a human-dug hypogea on the site of a Punic necropolis. The aim of the work was to obtain detailed 3D documentation of the indoor and outdoor spaces through the integration of mobile laser scanning and aerial photogrammetry survey, and to develop a virtual web navigation system for the remote exploration of the site. The indoor/outdoor web navigation system provides users with a simple, web-browser-based 3D visualization, enabling the dissemination of the monuments' knowledge on the web through an economically sustainable solution based on open-source technologies.