The Value of Complementarity. Integrating the Evidence from Air Survey and ALS in Bohemia

Abstract

This paper offers a contribution to discussion of the value of integrating different airborne perspectives for landscape prospection. A case study in Bohemia, Czech Republic, illustrates how the integration of the results of a long-term programme of aerial reconnaissance and recently acquired airborne laser scanning (ALS) (LiDAR) data has significantly improved the methodology and knowledge dividend for the study of past landscapes and settlements. Three types of featuresbarrows/ring ditches, a hillfort, and a nineteenth century artillery redoubtshave been surveyed repeatedly in order to detect the degree to which sites known from differential cropmarking in arable crops are also evident in ALS-derived digital terrain models (DTMs), and vice versa. It is noted that components of the hillfort and redoubts are clearly evident in the DTMs despite lying in fields that have been intensively cultivated for many decades at least, and are not easily recognized from the ground because their outline is so smoothed. This study illustrates the complementarities of cropmark aerial survey and ALS even in heavily ploughed environments, where there is often an assumption that features recorded as cropmarks have no surface expression, when in fact this often depends on the scale of the features.

From Air Survey to GIS-Aided Mapping, Photogrammetry-Based 3D Modelling and the Virtual Reconstructions of Czech Lowland Crop-Marked Archaeological Sites / Od leteckého průzkumu a mapování k tvorbě digitálního výškopisného modelu a 3D virtuálních rekonstrukcí lokalit identifikovaných prostřednictvím porostových příznaků v nížinných oblastech Čech

“…The burial ground near Černouček, consisting of one circular and one square ditch enclosure, was the very first archaeological site discovered in Bohemia by aerial survey in 1991 (Gojda 1997). The area has long been photographed from an airplane and a drone, surveyed by the GPR station and measured using a magnetometer.…”

“…The presented hornwork military feature near the village of Poplze was the very first field fortification identified in the territory of Bohemia. However, the oldest aerial photographs show only a part of the ditch enclosure, which was originally interpreted as a possible part of the local settlement from the Late Bronze Age, or a multicultural hilltop settlement located in the neighbouring 'Viničky' position (Gojda 1997); only later was the feature captured in its entire floor plan, allowing for its correct interpretation (Smrž et al 1999, 335) 'forts'), which are either of the same floor plan type and are not interconnected by ditches, ramparts and parallel roads, or each was constructed on a different floor plan and their interconnection by a ditch line created a compact defence base. They were built either in front of bastion fortresses or near important landscape components (e.g., at the confluence of larger rivers) with strategic links to important roads, cities, etc.…”

The Potential of Aerial Reconnaissance in the Detection, Mapping and 3D Reconstruction Modelling of Crop-Marked Military Components of Bohemia’s Postmedieval and Early Industrial Landscape

“…A number of similar projects in the Czech Republic and abroad have shown the potential that the integration of these aforementioned resources offers [42][43][44][45]. Refer to [46] for a study of military sites in the context of the Thirty Years' War; to [47,48] for studies of the period from the 17th to the 19th century; and [34] for general information on the aforementioned integration, including three examples of studies dealing with two prehistoric and one modern monuments. The majority of field fortifications from the 17th to the 19th century are physically preserved in the forested environment (i.e., in the terrain relief), where these sites were exposed to less intensive human pressure after their abandonment and were located in agriculturally less fertile positions of uplands, highlands and hilly regions, suitable for cattle grazing rather than the cultivation of arable land.…”

“…A number of similar projects in the Czech Republic and abroad have shown the potential that the integration of these aforementioned resources offers [42][43][44][45]. Refer to [46] for a study of military sites in the context of the Thirty Years' War; to [47,48] for studies of the period from the 17th to the 19th century; and [34] for general information on the aforementioned integration, including three examples of studies dealing with two prehistoric and one modern monuments.…”

“…Obviously, the non-invasive ch acteristics of remote sensing also correspond to the current general trends in archaeolo cal practice which stress a more careful-i.e., non-invasive-approach to, and manipu tion of archaeological sources, making this approach highly useful, meaningful and tractive. Recently raised themes in this field include the analysis of historical/archival a ial photographs through modern methods [16], data gathering via crowdsourcing and tificial intelligence/automatic classification [17][18][19][20][21][22][23][24][25], the mapping and monitoring of e dangered heritage [26][27][28][29][30][31], and the methods used for detecting and enhancing buried mains of archaeological heritage [32][33][34][35][36][37]. Experience has made it possible to label archeological remote sensing (ARS) as a set of the most effective methods for uncovering buried ancient and historical features/sites of any kind [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”