Akragas from Above: UAV Multispectral Survey and Photogrammetric Mapping of the Valley of the Temples, Agrigento

In August 2017 the Parco Archeologico e Paesaggistico della Valle dei Templi (Agrigento, Sicily) and Duke University began a programme of unmanned aerial vehicle (UAV) mapping across the heart of ancient Akragas, pairing a senseFly eBee Plus fixed-wing platform with RGB, near-infrared, and red-edge sensors under RTK positioning. The project produced centimetre-resolution orthomosaics, digital surface models (DSMs), vegetation-index layers and photogrammetric 3D models covering roughly two square kilometres of the intramural landscape, together with a dedicated block over the San Nicola sector, where the theater of Akragas had been confirmed by geophysics and excavation only the year before. This article presents the survey architecture, the data products and a first analytical reading of the results against the current state of Akragantine urban archaeology. A 5 cm full-site DSM renders the terraced urban plateau, the excavated insulae of the Hellenistic-Roman quarter and a fabric of candidate buried features as measurable micro-relief; near-infrared and red-edge mosaics, flown at the height of the summer drought, record the vegetation-stress patterning through which the unexcavated city writes itself into the modern surface; and a fully georeferenced 3D map links temples, agora, theater and landscape into a single analytical frame. Read alongside the revived excavation programs in the central public area - which have shown that even the city's grid plan requires re-verification on the ground - the survey demonstrates the role of fixed-wing multispectral photogrammetry at large classical sites: not an illustration of what is known, but an instrument for deciding where to look next.