Correlation among Earthwork and Cropmark Anomalies within Archaeological Landscape Investigation by Using LiDAR and Multispectral Technologies from UAV

Abstract

This project aimed to systematically investigate the archaeological remains of the imperial Domitian villa in Sabaudia (Italy), using different three-dimensional survey techniques. Particular attention in the research was paid to the identification and documentation of traces that buried structures left on the surface occupied by the villa, which extended for 46 hectares, an area that was fully covered with structures. Since a dense pine forest was planted during the 1940s and is currently covering the site, this contribution investigates particularly the correlation among the presence of cropmarks, identifiable with the processing of multispectral maps and vegetation indices from RGB images, and earthwork anomalies identified in a Digital Terrain Model (DTM) built, by utilizing a light detection and ranging (LiDAR) flight from an Unmanned Aerial Vehicle (UAV). The study demonstrates how the use of vegetation maps—calculated starting from RGB and multispectral aerial photos—can provide a more expeditious preliminary analysis on the position and extension of areas characterized by the presence of buried structures, but also that, in order to investigate in-depth a context in similar conditions, the most effective approach remains the one based on LiDAR technology. The integration between the two techniques may prove fruitful in limiting the extension of the areas to be investigated with terrestrial survey techniques.

Systematic Approach for Remote Sensing of Historical Conflict Landscapes with UAV-Based Laserscanning

“…This may be due to the fact that they are underground anomalies or have been backfilled (in the case of concave-shaped remains) or eroded (in the case of convex-shaped remains) over time. Examples of (B) include human remains and clandestine mass graves (if no burial mounds are visible on site) [ 45 , 46 ] or other buried historical evidence like earthwork anomalies [ 13 ] and remains of objects embedded in the ground [ 40 ].…”

“…For instance, Ronchi et al [ 13 ] showed that LiDAR outperforms RGB or multispectral approaches in the context of terrain anomaly identification. A LiDAR system generally consists of a single-wavelength laser that typically operates at a near-infrared wavelength.…”

“…For example, it could be that flight parameters are set unfavorably with respect to the conditions in the particular study area, so that certain terrain anomalies cannot be detected by the system. However, the flexibility of UAV-LiDAR, e.g., the possibility of adapting the flight planning individually and adjusting the flight parameters depending on the application and research question, is one of the advantages of this technique compared to airplane-based LiDAR [ 13 , 31 , 35 ].…”

Perceived Usefulness of Airborne LiDAR Technology in Road Design and Management: A Review

“…The combination of UAV and LiDAR provides excellent data [21]. Data from LiDARs are able to produce earthworks information [119], whereas images from UAVs provide a clear picture of the study area [120,121]. Apart from that, the issue of limited budget allocation is raised in the small and medium-scale designs for using airborne LiDAR [19].The use of UAVs is considered as another good alternative for this situation [122].…”

Preliminary Results of a Hybrid Thermoelectric Propulsion System for a Multirotor UAS with Active Rectifying, Electronic Throttle Control and Supercapacitors

“…To the best of the authors' knowledge, the only multirotor UAS capable of flying for more than 60 min, thanks to an exquisite aerodynamic design, a light carbon-fibre cell and the use of Lithium-Ion cells, is CONDOR™, manufactured by the Spanish company Dronetools™ (Gelves-Seville) [7] Although a maximum flight time on the verge of an hour for a multirotor UAS is an exceptional achievement, it is clearly not sufficient when reasonably large payloads, such as Light Detection and Ranging Systems (LiDAR), must be used [8], or when lower weight payloads are installed but the operation involves the inspection of large expanses of terrain [9][10][11]. The market for H-UAS and hybrid generators is very limited.…”