Documentation and Analysis of Archaeological Sites Using Aerial Reconnaissance and Airborne Laser Scanning (original) (raw)
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Airborne laser scanning for the management of archaeological sites in Lorraine (France)
COWLEY D. C. (ed.), Remote Sensing for Archaeological Heritage Management. Proceedings of the 11th EAC Heritage Management Symposium, Reykjavik, Iceland, 25-27 March 2010, 2011
Some 40 per cent of Europe is farmed and 47 per cent forested. The future of the majority of Europe's archaeological sites therefore depends on rural land uses that lie outside the spatial planning and development control systems of its various nation states. This volume, produced by the European Association of Archaeologists (EAA) and Europae Archaeologiae Consilium (EAC) Joint Working Group on Farming, Forestry and Rural Land Management, examines the challenges posed by agriculture, forestry and other rural land uses in terms of the long-term conservation of Europe's archaeological sites and the management of its historic landscapes.
Towards an improved archaeological record through the use of airborne laser scanning
Space, Time and Place. 3rd International Conference on Remote Sensing in Archaeology (eds. M. Forte, S. Campana & C. Liuzza), 2010
The archaeological survey situation in Norway is rather uneven because it is largely settled farmland areas that have been the object of systematic survey campaigns. The archaeological records for forests and other outfield areas are very flawed, which makes proper cultural heritage management of these areas difficult. This paper outlines how airborne laser scanning (ALS) can contribute to an improvement in the situation. The advantages and challenges of using ALS are discussed and analysis of statistics from two completed ALS projects shows how large a percentage of the cultural remains it is possible to detect, to what degree we have succeeded with interpretation of the digital elevation models and the accuracy of remote sensing based documentation of the remains. The conclusion is that ALS can successfully be used to conduct remote sensing based surveys and documentation of cultural monuments and remains with competitive accuracy in all kinds of landscape. Forest and outfield areas which so far have been given little attention can now be surveyed efficiently and improve research and cultural heritage management.
Archaeological applications using airborne laser scanning (ALS) are increasing in number. Since the production of ALS-derived digital terrain models (DTM) involves a considerable amount of money, most applications use general purpose ALS data, which are usually cheaper and sometimes even provided for free for scientific applications. The main problem that comes with this kind of data is the frequent lack of meta-information. The archaeologist often does not get the information about original point density, time of flight, instrument used, type of flying platform, filter and DTM generation procedure etc. Therefore, ALS becomes a kind of “black box”, where the derived DTM is used without further knowledge about underlying technology, algorithms, and metadata. Consequently, there is a certain risk that the data used will not be suitable for the archaeological application. Based on the experience of a two-year project “LiDAR-Supported Archaeological Prospection in Woodland”, the paper will give a review on archaeological ALS, explain its the basic process, demonstrate its potential for landscape archaeology especially in densely forested areas, and draw the attention to some critical parameters of ALS, which should be known to the user. Finally, further issues, which need to be solved in near future, are discussed.
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLI-B5, 2016
This paper deals with the non-destructive documentation of the "Radkov" (Svitavy district, Czech Republic) archaeological site. ALS, GPR and land survey mapping will be used for the analysis. The fortified hilltop settlement "Radkov" is an immovable historical monument with preserved relics of anthropogenic origin in relief. Terrain reconnaissance can identify several accentuated objects on site. ALS enables identification of poorly recognizable archaeological objects and their contexture in the field. Geophysical survey enables defunct objects identification. These objects are hidden below the current ground surface and their layout is crucial. Land survey mapping provides technical support for ALS and GPR survey. It enables data georeferencing in geodetic reference systems. GIS can then be used for data analysis. M. Cejpová and J. Němcová have studied this site over a long period of time. In 2012 Radkov was surveyed using ALS in the project "The Research of Ancient Road in Southwest Moravia and East Bohemia". Since 2015 the authors have been examining this site. This paper summarises the existing results of the work of these authors. The digital elevation model in the form of a grid (GDEM) with a resolution 1 m of 2012 was the basis for this work. In 2015 the survey net, terrain reconnaissance and GPR survey of two archaeological objects were done at the site. GDEM was compared with these datasets. All datasets were processed individually and its results were compared in ArcGIS.
Remote Sensing, 2020
This paper gives a presentation of how airborne laser scanning (ALS) has been adopted in archaeology in the North over the period 2005-2019. Almost two decades have passed since ALS first emerged as a potential tool to add to the archaeologist's toolbox. Soon after, it attracted the attention of researchers within archaeological communities engaged with remote sensing in the Fenno-Scandinavian region. The first archaeological ALS projects gave immediate good results and led to further use, research, and development through new projects that followed various tracks. The bulk of the research and development focused on studying how well-suited ALS is for identifying, mapping, and documenting archaeological features in outfield land, mainly in forested areas. The poor situation in terms of lack of information on archaeological records in outfield areas has been challenging for research and especially for cultural heritage management for a long period of time. Consequently, an obvious direction was to study how ALS-based mapping of cultural features in forests could help to improve the survey situation. This led to various statistical analyses and studies covering research questions related to for instance effects on detection success of laser pulse density, and the size and shape of the targeted features. Substantial research has also been devoted to the development and assessment of semi-automatic detection of archaeological features based on the use of algorithms. This has been studied as an alternative approach to human desk-based visual analyses and interpretations of ALS data. This approach has considerable potential for detecting sites over large regions such as the vast roadless and unbuilt wilderness regions of northern Fennoscandia, and has proven highly successful. In addition, the current review presents how ALS has been employed for monitoring purposes and for landscape studies, including how it can influence landscape understanding. Finally, the most recent advance within ALS research and development has been discussed: testing of the use of drones for data acquisition. In conclusion, aspects related to the utilization of ALS in archaeological research and cultural heritage management are summarized and discussed, together with thoughts about future perspectives.
AIRBORNE LASER SCANNING AND IMAGE PROCESSING TECHNIQUES FOR ARCHAEOLOGICAL PROSPECTION
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XL-5, 2014
Aerial photography was, for decades, an invaluable tool for archaeological prospection, in spite of the limitation of this method to deforested areas. The airborne laser scanning (ALS) method can be nowadays used to map complex areas and suitable complement earlier findings. This article describes visualization and image processing methods that can be applied on digital terrain models (DTMs) to highlight objects hidden in the landscape. Thanks to the analysis of visualized DTM it is possible to understand the landscape evolution including the differentiation between natural processes and human interventions. Different visualization methods were applied on a case study area. A system of parallel tracks hidden in a forest and its surroundings-part of old route called "Devil's Furrow" near the town of Sázava was chosen. The whole area around well known part of Devil's Furrow has not been prospected systematically yet. The data from the airborne laser scanning acquired by the Czech Office for Surveying, Mapping and Cadastre was used. The average density of the point cloud was approximately 1 point/m 2. The goal of the project was to visualize the utmost smallest terrain discontinuities, e.g. tracks and erosion furrows, which some were not wholly preserved. Generally we were interested in objects that are clearly not visible in DTMs displayed in the form of shaded relief. Some of the typical visualization methods were tested (shaded relief, aspect and slope image). To get better results we applied image-processing methods that were successfully used on aerial photographs or hyperspectral images in the past. The usage of different visualization techniques on one site allowed us to verify the natural character of the southern part of Devil's Furrow and find formations up to now hidden in the forests.
The Application of Airborne Laser Scanning Systems in Archaeology: Moving beyond pretty pictures
The last decade, Airborne Laser Scanning (ALS) has proven to be a valuable tool for large-scale archaeological survey and mapping. It has especially revolutionized survey of densely forested areas, thanks to its ability to penetrate vegetation canopies. In recent years, research interest has moved beyond producing pretty pictures and has focused more on technological issues, e.g. the influence of point density and the benefits of full-waveform systems. Despite its potential, ALS also has limitations and the use of ALS data encounters challenges such as data filtering, classification and issues of interpretation. This review presents an overview of ALS technology for archaeological purposes, taking into account its benefits and limitations.
Airborne laser scanning and archaeological interpretation – bringing back the people
As with every other prospection method, data provided by Airborne Laser Scanning (ALS) have to be interpreted to add archaeological value. Interpretation is considered in a holistic way, where the whole chaîne opératoire from project planning to the final filtered ALS dataset has to be evaluated to estimate the archaeological potential. Decisions upon the most useful combination of visualization techniques, interpretive mapping (usually done in a GIS-based environment), and ground inspection are strongly interrelated and should not be done in isolation. Additionally, integrated other sources of information (e.g. other prospection methods, historical documentary research) the detailed topographical information from ALS can help to deepen understanding of the archaeology in its landscape setting on multiple scales. This is demonstrated in a case study of a religiously-motivated choice of location for a Carmelite friary. Going beyond standard descriptive mapping, the choice of location is interpretively explained combining etic and emic observations based on multi-scale ALS information and the inclusion of historical context and perception variables. The case study demonstrates that it is not useful to distinguish between true and false interpretations, but between good and bad ones. This distinction has to be based on the arguments used and whether the interpreter was following scientific rules. A good interpretation should integrate information from multiple sources generating archaeological information, which extends beyond the obvious.