Medieval Archaeology Under the Canopy with LiDAR. The (Re)Discovery of a Medieval Fortified Settlement in Southern Italy

Nicola Masini,Vincenzo Fundone,Michele Sedile,Biagio Lacovara,Maria Sileo,Fabrizio Gizzi,Antonio Pecci,Marilisa Biscione,Rosa Lasaponara

doi:10.3390/rs10101598

Abstract

Despite the recognized effectiveness of LiDAR in penetrating forest canopies, its capability for archaeological prospection can be strongly limited in areas covered by dense vegetation for the detection of subtle remains scattered over morphologically complex areas. In these cases, an important contribution to improve the identification of topographic variations of archaeological interest is provided by LiDAR-derived models (LDMs) based on relief visualization techniques. In this paper, diverse LDMs were applied to the medieval site of Torre Cisterna to the north of Melfi (Southern Italy), selected for this study because it is located on a hilly area with complex topography and thick vegetation cover. These conditions are common in several places of the Apennines in Southern Italy and prevented investigations during the 20th century. Diverse LDMs were used to obtain maximum information and to compare the performance of both subjective (through visual inspections) and objective (through their automatic classification) methods. To improve the discrimination/extraction capability of archaeological micro-relief, noise filtering was applied to Digital Terrain Model (DTM) before obtaining the LDMs. The automatic procedure allowed us to extract the most significant and typical features of a fortified settlement, such as the city walls and a tower castle. Other small, subtle features attributable to possible buried buildings of a habitation area have been identified by visual inspection of LDMs. Field surveys and in-situ inspections were carried out to verify the archaeological points of interest, microtopographical features, and landforms observed from the DTM-derived models, most of them automatically extracted. As a whole, the investigations allowed (i) the rediscovery of a fortified settlement from the 11th century and (ii) the detection of an unknown urban area abandoned in the Middle Ages.

Highlights

The identification, analysis, and survey of archaeological remains and proxy indicators is a complex challenge especially in areas covered by dense vegetation, as wooded and forest land
We focused our investigations on the hilly plateau indicated with the red circle in Figure 1c, thought to be a settlement founded at the beginning of the XI century, along with other sites such as Civitate, Dragonara, Fiorentino, Montecorvino, Tertiveri, as a node of the Byzantine Lime [25]
For the purpose of our investigations in Torre di Cisterna, all the LiDAR-derived models (LDMs) mentioned in Section 2.5.2 have been applied to enhance the topographical relief of archaeological interest

Summary

Introduction

The identification, analysis, and survey of archaeological remains and proxy indicators is a complex challenge especially in areas covered by dense vegetation, as wooded and forest land. The difficulties in the documentation, survey, and material collection increase in areas characterized by dense understory vegetation In this condition, the presence of scattered building materials further increases the difficulty in the identification of archaeological proxy indicators linked to micro-topographical and landform variations. The presence of scattered building materials further increases the difficulty in the identification of archaeological proxy indicators linked to micro-topographical and landform variations To face these challenges, remote sensing based on LiDAR (Light Detection and Ranging) can be fruitfully applied to achieve unique performance in detecting and surveying archaeological features and remains, even in rain forest and densely vegetated areas with close canopy [1]. In Italy, the integrated use of LiDAR, UAV, aerial thermography, and multispectral satellite imagery, in the Etruscan site of San Giovenale at about 60 km NW of Rome, revealed a large variety of archaeological features, including a necropolis and a road, tumulus under canopy, most of them under canopy [7]

Methods

Results

Conclusion