(IBAM – CNR, Lecce, Italy)

Outline: 3D analysis and visualization of GPR data to identification and positioning buried archaeological remains

Abstract: Ongoing and extensive urbanization may threaten important archaeological structures that are still buried in the urban areas. Ground Penetrating Radar method is the most promising alternative for resolving buried archaeological structures in urban territories. In this paper a case study that involves a geophysical survey employing the surface three-dimensional (3D) GPR techniques, in order to archaeologically characterize the investigated areas.

The field site is located in the peripheral areas of Ugento (Puglia, Italy); the modern city overlaps two thirds of an ancient settlement, the most extensive of ancient Messapia.

GPR measurements, integrated with archaeological and topographical surveys by using a differential GPS, were carried out in three test sites regarding sectors of the Messapian city walls (second half of the 4th century BC) and the nearby necropolises, characterized by graves, sarcophagi and stone banks. One area, in the northern periphery of the ancient settlement regards a sector of the city walls now buried, in a not an urbanized territory; the other two areas are in roads (via Peri and via Petrarca) located along the western periphery of the settlement and concern two ancient gates, partially excavated in 1980s and now buried, inside the urban area of the modern city.

The GPR data were collected along a dense network of parallel profiles. The GPR sections were processed applying specific filters to the data in order to enhance their information content. Finally, GPR data were visualized in 3D using both the horizontal depth slices and the iso-surface volumes that represent the 3D variation of the physical properties in the subsoil of surveyed area. The GPR images significantly contributed in reconstructing the complex subsurface properties in these modern urban areas. Strong GPR reflections anomalies were correlated with possible archaeological structures; they were integrated in the digital archaeological map of the city.

Keywords: urban archaeology, GPR; archaeological maps, GIS, GPS