Radiometric Information from Airborne Laser Scanning for Archaeological Prospection (original) (raw)
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MULTI-WAVELENGTH AIRBORNE LASER SCANNING FOR ARCHAEOLOGICAL PROSPECTION
In: Pierre Grussenmeyer (Hg.): XXIV International CIPA Symposium 02–06 September 2013, Strasbourg, France. Göttingen: Copernicus Publications (ISPRS Archives, Volume XL-5/W2), S. 119–124.
Airborne laser scanning (ALS) is a widely used technique for the sampling of the earth’s surface. Next to the widely used geometric information current systems provide additional information about the signal strength of each echo. In order to utilize this information, radiometric calibration is essential. As a result physical observables that characterise the backscatter characteristic of the sensed surface are available. Due to the active illumination of the surfaces these values are independent of shadows caused by sunlight and due to the simultaneously recorded 3D information a single-channel true orthophoto can be directly estimated from the ALS data. By the combination of ALS data utilizing different laser wavelengths a multi-wavelength orthophoto of the scene can be generated. This contribution presents, next to the practical calibration workflow, the radiometric calibration results of the archaeological study site Carnuntum (Austria). The area has been surveyed at three different ALS wavelengths within a very short period of time. After the radiometric calibration of each single ALS wavelength (532nm, 1064nm and 1550nm) a multi-channel ALS orthophoto is derived. Subsequently, the radiometric calibration results of the single- and multi-wavelength ALS data are studied in respect to present archaeological features. Finally, these results are compared to the radiometric calibration results of an older ALS data acquisition campaign and to results of a systematic air photo interpretation.
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.
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.
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.
AIRBORNE LASER SCANNING AND LANDSCAPE ARCHAEOLOGY
Opuscula archaeologica 39/40(1), 2018
Airborne lidar (Light Detection And Ranging), ALS or ALSM (Airborne Laser Scanning, Airborne Laser Swath Mapping) is an active remote sensing technique , which records the surface of the earth using laser scanning. ALS allows very precise three-dimensional mapping of the surface of the earth, producing high-resolution topographic data, even where surface is obscured by forest and vegetation. The level of detail on digital surface and terrain models produced from high resolution ALS topographic data helps us enormously in identification of past events, which reworked and modified the surface of the earth. However , interpretation of ALS data poses much more than technical challenges. ALS does not provide only a layer of data, but offers a different view of landscape. What kind of landscapes do we see with ALS?
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.
AERIAL LASER SCANNING IN ARCHEOLOGY
cipa.icomos.org
Technology of aerial laser scanning is often well used for a DTM generation. The DTM (digital surface model) displayed in appropriate form, e.g. shaded surface, can be used as a data source for searching for archaeological sites. Aerial laser scanning data acquisition is unfortunately too expensive for noncommercial projects. It can be a solution to use the ALS data acquired primarily for another purpose by public service. In general, this data has lower density than the expensive custom-made data, but in a limited size can be borrowed for some research purpose. We tested the data from The Czech Office for Surveying, Mapping and Cadastre. The aim was to find if possible to use data characterized by a density of about 1 point/m 2 for archaeological research. We used the DTM in the form of shaded surface and inspected the data around few well known archaeological sites of different periods. It is also possible to use different outputs from the original DTM to better display terrain discontinuities caused by man's activity.
Making the most of airborne remote sensing techniques for archaeological survey and interpretation
The use of airborne remote sensing has found increasing popularity in the historic environment sector over the past decade. Many landscape projects across Europe are incorporating the application of archive airborne survey and increasing numbers are commissioning bespoke survey. This is particularly true for Airborne Laser Scanning (ALS), but despite a number of promising applications, digital spectral surveys have been less frequently utilised. Our understanding of the full potential of these rich data sources is still in its infancy. This paper provides a summary of current applications and highlights the need for research in three key areas to improve our applications of airborne remote sensing for research into the historic environment. It concludes by introducing a project established at Bournemouth University to develop a multisensor approach to airborne survey of liminal environments.
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.