From Urban Orientations to 3D Visualisation: Solar Irradiation in Pompeii within Ancient Virtual Skies

Virtual archaeology is here applied for the study of ancient Mediterranean cities. In particular, the present research aims to contextualise urban morphology within the wider local natural environment. In the analysis of urban orientation, the 2D study is brought forward towards a computer-based 3D visualisation of the city of Pompeii, with the archaeological structures placed within their natural digitalised landscape and skyscape. The given accuracy of the simulation assures its functionality as an additional tool for the research question and the investigation of the role of the sun within urbanistic practices in ancient Campania. Previous research has shown that the orientation of the Hellenistic streets in Pompeii coincides with the entrance of sunlight on summer solstice dawn. Symmetrically, on the south-western side, the last rays on winter solstice enter the town allowing a minimum irradiation even on the shortest day of the year. To further interpret this specific orientation in the context of sunlight irradiation, a 3D model was built and placed within the astronomical desktop planetarium software Stellarium, recreating ancient skies by correcting the sun position for Pompeii’s historical phases. The mountains visible around the site were also reconstructed from a 10 m DEM to show the correct rising and setting sun position. Light and shadows impacting on architectures were simulated, highlighting the role of the sun as an integrated and participatory aspect in the life of the city. Among the many advantages of implementing virtual archaeology, its importance for heritage communication and valorisation is also emphasised.