Tools from above: evaluating drone-borne aerial remote sensing systems for archaeological site and feature identification

Abstract

Archaeological investigations are rapidly changing due to developing digital technologies. They affect data collection, processing, interpretation, and analysis, but have spawned new approaches to archaeological investigations. One aspect of this change includes remotely piloted aircraft systems (RPAS or Unmanned Aerial Vehicles or UAVs, also commonly known as drones) that have utility in improving cost-effectiveness of site characterization and feature identification but may not be appropriate for every archaeological situation. These RPAS are rapidly improving, and becoming more affordable, powerful, and accessible. When employed with digital data processing methods, they offer an important tool for investigating natural and cultural landscapes. Compared with imagery from modern satellite and manned aircraft, low altitude drone data offer advantages in resolution, accuracy, and flexibility. Important emerging considerations involve the development of diverse drone-deployed sensors coupled with geomatic analysis, machine learning, and computer-aided enhancement of detected spatial patterns. This thesis explores the strengths and weaknesses of data collection and processing via aerial remote sensing, with particular attention to its utility for archaeological detection and characterization. It evaluates the efficacy and cost-effectiveness of unmanned aerial vehicles (UAVs) equipped with various sensors to aid archaeological investigation and site analysis. Further, a variety of data formats were integrated using geographic information systems (GIS). Information deriving from each of the remote sensing sensors used in this thesis demonstrated interpretive value. Efforts at validation of non-invasive archaeological interpretation involve direct visual confirmation of feature anomalies and positive spatial correlation of features of interest using optical remote sensing, legacy data, and georeferenced imagery. This study represents the first systematic evaluation of UAVs and sensor technologies for archaeological use in the Canadian Prairies. The research addressed three key questions through examples using both consumer and professional-grade UAVs: 1. Can consumer and professional-grade UAVs provide more comprehensive tools for archaeological site characterization? 2. Can these UAVs help overcome the physical and financial challenges associated with archaeological fieldwork? 3. What technical and regulatory obstacles hinder the routine integration of consumer and professional-grade UAVs in archaeological investigations? These questions are addressed with aerial data from three different archaeological site types from Manitoba, Canada: the pre-contact Lockport site (case study 1); the fur trade posts at Fort Ellice I and Fort Ellice II (case studies 2 and 3); and an undisclosed modern/historic cemetery (case study 4).