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

In order to locate historical traces, drone-based Laserscanning has become increasingly popular in archaeological prospection and historical conflict landscapes research. The low resolution of aircraft-based Laserscanning is not suitable for small-scale detailed analysis so that high-resolution UAV-based LiDAR data are required. However, many of the existing studies lack a systematic approach to UAV-LiDAR data acquisition and point cloud filtering. We use this methodology to detect anthropogenic terrain anomalies. In this study, we systematically investigated different influencing factors on UAV-LiDAR data acquisition. The flight parameters speed and altitude above ground were systematically varied. In addition, different vegetation cover and seasonal acquisition times were compared, and we evaluated three different types of filter algorithms to separate ground from non-ground. It could be seen from our experiments that for the detection of subsurface anomalies in treeless open terrain, higher flight speeds like 6m/s were feasible. Regarding the flight altitude, we recommend an altitude of 50–75m above ground. At higher flight altitudes of 100–120m above ground, there is the risk that terrain characteristics smaller than 50cm will be missed. Areas covered with deciduous forest should only be surveyed during leaf-off season. In the presence of low-level vegetation (small bushes and shrubs with a height of up to 2m), it turned out that the morphological filter was the most suitable. In tree-covered areas with total absence of near ground vegetation, however, the choice of filter algorithm plays only a subordinate role, especially during winter where the resulting ground point densities have a percentage deviation of less than 6% from each other.

An Introduction to Geophysical and Geochemical Methods in Digital Geoarchaeology

Archaeological geophysics is a range of techniques for the minimally invasive, remote investigation of the physical parameters of the nearsurface environment. This suite of methods is complementary to archaeological survey or excavation as it can provide information about the stratigraphy of the survey area, locate anthropogenic traces of the past, document their spatial dimensions and—under ideal conditions—explore the physical properties of subsurface materials. Both material culture items such as a building foundations and indirect indications of anthropogenic activity such as subsurface disturbance or evidence of burning are excellent direct targets for geophysical investigations since they can be differentiated on the basis of their material properties from the wider soil context. In addition to directly locating archaeological material, geophysical techniques can make an important contribution to geoarchaeological investigations by elucidating the site stratigraphy and mapping its lateral geometry. In some cases, such as when locating prehistoric material buried offshore or within open Palaeolithic sites, the reconstruction of past landscapes may make a more important contribution to archaeological investigations than the direct geophysical detection of archaeological materials.Different material culture items have characteristic physical properties (such as electrical resistance or conductivity, magnetic susceptibility) and so require different instrumentation for effective detection. The main techniques for archaeological prospection include magnetometer, resistance meter, magnetic susceptibility meter, ground-penetrating radar and electromagnetic induction meter. Apart from that, seismic methods (reflection and refraction seismics), gamma spectroscopy and gravity techniques are also used in certain circumstances. Unfortunately, there is no standard approach for the application of one specific geophysical method for all archaeological materials in all geological environments. The success of geophysical prospection techniques depends on a combination of soil and sediment characteristics as well as depth below surface and preservation of archaeological findings. In order to achieve the most reliable results and enhance the chance of detecting archaeological material, an integrated, multi-method approach is suggested.In addition to field surveying, the effective processing of measured geophysical data is a crucial part of the interpretation process. Data processing aims to enhance signals of interest in order to better delineate archaeological and geological features. It helps to produce more interpretable results and therefore facilitates and fosters collaboration between geophysicists and archaeologists.

Magnetic Mapping and Seismoacustic Investigations in the Altinum Submerged Archaeologic Site

The roman fortress from Macuca Hill, identifi ed by Romanian archaeologists, until now, as the garrison Altinum, northof Oltina village, northeast of Oltina Lake, has no observable features to be ascribed to late Roman period. On the eastern bank of the lake the team in charge with the archaeological research in Capul Dealului site made land surveys on the northern slopes of Macuca Hill, looking to the Danube’s Island Ostrovu Iepuraçu (Rabbit’s Island), some hundred meters north of the timber and earth playing-card fort described a century ago by Pamfi l Polonic. The archaeologists from Constanta found in 2006 survey convincing remains of a monumental stone wall, hidden in the forest. If the remains depend of a fortress, or of a harbor facility, only the seimoacustic and magnetometric investigation research will answer. In this work we present the results of a multidisciplinary study for characterising the archaeological site of Altinum (Dobrudja, Southern Romania). The investigation has been performed by means of the integrated use of two different high resolution and no invasive geophysical techniques: magnetic mapping, and sidescansonar measurements. The integrated approach allows us to detect submerged archaeological structures. In particular, our results helped to define spatial pattern of the submerged remains, to define the geometry of the anthropogenic settlements and to obtain detailed information about the composition and the manufacturing processes of different building materials. Magnetic prospecting represents one of the widest employed tools in the geophysical research applied to the archaeological studies. This technique provides a great amount of high-resolution magnetic data in a very small time: up to ten measurements per second. Moreover, because the magnetic equipment is a portable instrument assembled by the user, it may be used in every configuration for investigation the submerged archaeological site. Sidescansonar profiling is widely applied to support the magnetometric investigation and archaeological prospection. In particular, three-dimensional modelling of sidescansonar surveys are increasing in popularity, in fact 3D models are much more valuable for archaeological feature interpretation. However, to obtain a higher horizontal and vertical resolution, a sub-metre line spacing is generally needed, making the 3D acquisition more expensive in time in respect of magnetic measurements. The magnetic survey on the waterhas been carried out using a caesium vapour marine magnetometer G-882 GEOMETRICS and proton magnetometer G-856 for diurnal variations of the natural magnetic field. The sidescansonar system (Klein Sonar Pro) has two working frequencies (445 KHz and 900 KHz). The 445 KHz frequency was used for discover submerged walls and other archaeological structure. The integration between these two techniques allowed us to define the geometry and the depth of a buried structures.

The Seat of the Roman Governor at Carnuntum (Pannonia Superior)

The Roman site of Carnuntum was once a flourishing center on the frontiers of the Roman Empire. In its heyday as the capital of the province of Pannonia superior, Carnuntum probably covered an area of almost 9 km². The whole site was divided into a military settlement (castra and canabae legionis) and a civil town (municipium/colonia). Through a large-scale archaeological prospection project, this huge area could be investigated and analyzed in great detail using a wide variety of nondestructive prospection methods. One of the main discoveries of the project was observed in the military settlement, where it was possible to identify a previously unknown military camp, interpreted as the garrison of the governor’s guard, the castra singularium. Through the topographic analysis of the immediate surroundings, the Roman fort was determined to be embedded in a large administrative complex related to the governor’s seat in Carnuntum. This article presents these new discoveries and shows what an important part they formed in the administration of the Roman province of Upper Pannonia.

GPR Data Interpretation Approaches in Archaeological Prospection

This article focuses on the possible drawbacks and pitfalls in the GPR data interpretation process commonly followed by most GPR practitioners in archaeological prospection. Standard processing techniques aim to remove some noise, enhance reflections of the subsurface. Next, one has to calculate the instantaneous envelope and produce C-scans which are 2D amplitude maps showing high reflectivity surfaces. These amplitude maps are mainly used for data interpretation and provide a good insight into the subsurface but cannot fully describe it. The main limitations are discussed while studies aiming to overcome them are reviewed. These studies involve integrated interpretation approaches using both B-scans and C-scans, attribute analysis, fusion approaches, and recent attempts to automatically interpret C-scans using Deep Learning (DL) algorithms. To contribute to the automatic interpretation of GPR data using DL, an application of Convolutional Neural Networks (CNNs) to classify GPR data is also presented and discussed.

Airborne LiDAR Point Cloud Processing for Archaeology. Pipeline and QGIS Toolbox

The use of topographic airborne LiDAR data has become an essential part of archaeological prospection. However, as a step towards theoretically aware, impactful, and reproducible research, a more rigorous and transparent method of data processing is required. To this end, we set out to create a processing pipeline for archaeology-specific point cloud processing and derivation of products that are optimized for general-purpose data. The proposed pipeline improves on ground and building point cloud classification. The main area of innovation in the proposed pipeline is raster grid interpolation. We have improved the state-of-the-art by introducing a hybrid interpolation technique that combines inverse distance weighting with a triangulated irregular network with linear interpolation. State-of-the-art solutions for enhanced visualizations are included and essential metadata and paradata are also generated. In addition, we have introduced a QGIS plug-in that implements the pipeline as a one-step process. It reduces the manual workload by 75 to 90 percent and requires no special skills other than a general familiarity with the QGIS environment. It is intended that the pipeline and tool will contribute to the white-boxing of archaeology-specific airborne LiDAR data processing. In discussion, the role of data processing in the knowledge production process is explored.

Archaeological Prospection in Wetlands—Experiences and Observations from Ground-Penetrating Radar Surveys in Norwegian Bogs

Wetlands are of immense importance for archaeological research due to excellent preservation conditions for organic material. However, the detection and registration of archaeological remains in waterlogged areas, such as peatlands, bogs, mires, or lakeshores are very challenging. Alternative methods that can support traditional archaeological registrations and that can help to survey wetlands more efficiently are needed. One goal of the “Arkeologi på nye veier” (Archaeology on new ways) project, initiated by Nye Veier AS, was to develop and test a practical solution for non-invasive geophysical surveys in wetland environments in support of traditional archaeological investigations. For that purpose, a custom GPR system for wetland investigations was assembled, tested and applied at Gausdal (Flekkefjord municipality, Agder county) in Norway within the E39-southwest infrastructure project. The GPR survey resulted in promising data, clearly showing the buried remains of an old road within the investigated area. This case study demonstrated the potential of GPR measurements in peatlands as a valuable asset for archaeological registration projects in such environments. However, despite these first encouraging results, wetlands remain very challenging environments, and realistic expectations, as well as a good understanding of the potential and limitations of this approach are a prerequisite for meaningful surveys.