The Hidden Cairns—A Case Study of Drone-Based ALS as an Archaeological Site Survey Method

Abstract

Conducting archaeological site surveys is time consuming, and large sites may have many small features or structures that are difficult to locate and interpret. Vegetation cover and dense forest hide small structures, like cairns, while at the same time forest cover can cause problems for LiDAR tools. In this case study, drone-based ALS (airborne laser scanning) was tested as an archaeological site survey tool. The research site was complex and located partially in a forested area, which made it possible to evaluate how forest cover affects data. The survey methods used were rather simple: visual analysis, point density calculations in the forest area, and, for site interpretation purposes, digitizing observations and viewshed analysis. Using straightforward methods allowed us to evaluate the minimum time and skills needed for this type of survey. Drone-based ALS provided good results and increased knowledge of the site and its structures. Estimates of the number of cairns interpreted as graves more than doubled as a result of the high-accuracy ALS data. Based on the results of this study, drone-based ALS could be a suitable high-accuracy survey method for large archaeological sites. However, forest cover affects the accuracy, and more research is needed.

Digging through Databases—A Case Study of Iron Age Sites in Finland by Generating and Analysing Keywords

“…The villages of Kalho and Pohjola seem to form another possible cluster together. In the Kalho area, there is an especially large and complex site that includes many cairns, which are most likely burial cairns [33]. Today, the Kalho and Pohjola area is not so densely built up, which gives the area a high archaeological value as it is less disturbed.…”

UAV LiDAR in coastal environments: Archaeological case studies from Tierra del Fuego, Argentina, and Vega, Norway

“…Not only does size matter: Shape is also decisive for identification. Small features with a distinct geometric shape are easier to identify in a LiDAR data set than larger features without such characteristics (Emmitt et al, 2020; Risbøl et al, 2013; Roiha et al, 2021). Accordingly, small, subtle and hardly visible features ignored during fieldwork are often identifiable when observed from above on a LiDAR‐generated model (Barbour et al, 2019; Casana et al, 2021; Davis et al, 2019).…”

“…Although the use of UAV LiDAR in archaeology remains limited compared with conventional LiDAR, it has been successfully employed to detect archaeological features under tree canopies in various environments across the world. This includes building foundations and field systems in Hawaii (Casana et al, 2021; McCoy et al, 2022), building features from a deserted village in Italy (Masini et al, 2022), deserted settlements in Spain (Monterroso‐Checa et al, 2021), grave mounds and charcoal production sites in Norway (Risbøl & Gustavsen, 2018), graves and clearance cairns in Finland (Roiha et al, 2021), building features and field systems in Mexico (Schroder et al, 2021), mapping historical conflict landscapes in Germany (Storch et al, 2022), an ancient walled settlement in Peru (VanValkenburgh et al, 2020) and mounds and building foundations in China (Zhou et al, 2020). Most of these projects involved field verifications of LiDAR identifications or evaluations of previous field surveys by employing LiDAR mapping.…”

Bibliometric Analysis of Spatial Technology for World Heritage: Application, Trend and Potential Paths

“…The nodes are interlinked with each other. In recent years, UAV has been widely used as a member of remote sensing technology for heritage exploration, conservation, documentation and survey monitoring [99][100][101][102][103]. "The 'GIS' nodes are mainly linked to the 'Tourism' node and the 'World Heritage' node.…”