Airborne LiDAR-Derived Digital Elevation Model for Archaeology (original) (raw)
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Slovak Journal of Civil Engineering, 2022
LiDAR-derived digital elevation models (DEMs) have transformed the archaeological study of landscape features, broadened our technical capabilities, and enhanced the accuracy with which terrain relief is described. These models also place demands on how researchers and analysts interpret DEM content in the context of the modern landscape. LiDAR-based DEMs contain modern man-made structures that can significantly influence model properties. Although data are usually filtered and some of these artificial features are removed during bare-earth classification, many terrain interventions remain visible. This large-scale case study applies established methods to a freely available DEM of the Czech Republic in an attempt to evaluate differences between original and filtered DEMs. It applies a fully automated filtering procedure using vector topographic maps to avoid manual corrections that would make the procedure problematic when used on a macro scale. The results of our archaeological GIS analysis demonstrate that this procedure, despite its relative simplicity, can achieve a significantly better representation of a landscape compared to that offered by an unfiltered DEM. Finally, we propose a series of future steps with a view to developing a more comprehensive and accurate model and overcoming its limitations.
Interpolation of airborne LiDAR data for archaeology
The use of topographic airborne LiDAR data has become an essential part of archaeological prospection, and the need for an archaeology-specific data processing workflow is well established. However, interpolation, an important step in which the digital elevation model is derived from the classified point cloud, has received little attention from archaeologists. This processing step has a direct impact on the accuracy and visual performance of the digital elevation model, but remains a challenge despite numerous studies. Most studies have compared the accuracy of different interpolators (with conflicting results), but very few compare the visual performance. Also, there are no archaeology-specific studies. This article addresses this problem by providing an archaeologyspecific visual performance assessment of six of the most commonly used interpolators. The data was tested at four European test sites with innovative use of the triangular assessment method. Kriging was the best interpolator in undersampled areas, and inverse distance weighting was a distant second. In other areas, triangulation with linear interpolation was marginally better than kriging. However, when availability and computational costs are also taken into account, inverse distance weighting is currently the most suitable archaeology-specific interpolator. In addition, we propose a hybrid interpolator that combines the strengths of triangulation with linear interpolation and inverse distance weighting (QGIS plug-in). All results are to be considered Europeandata specific.
Extraction of archaeological features from high-resolution LIDAR data
In May 2009, the State Office for Cultural Heritage Management Baden-Württemberg launched a three-year project aimed at the complete archaeological mapping of Baden-Württemberg using highresolution airborne LIDAR (Light Detection And Ranging) data, covering an area of 35751 km2. The goal is the verification and extension of the existing archaeological data base. To achieve this goal, a data processing method and workflow for the extraction of Local Relief Models from LIDAR-based Digital Elevation Models was developed. Colour-coded maps of these Local Relief Models are found to be a valuable tool for archaeological prospection. First results of the project confirm the feasibility of using LIDARbased data for the archaeological mapping of very large areas.
LIDAR -based surface height measurements: applications in archaeology
L ight detection and ranging (LIDAR) is an airborne remote-sensing technique that can measure terrain elevation. The first LIDAR surface height measurements for parts of the Netherlands became available in 2001. By 2004, the database covered the entire country. The first digital elevation models (DEM) based on these data showed more landscape detail than ever achieved before. Studies of applications in geomorphological mapping were quickly published after the release of the first databases . The first application to archaeological research was a paleogeographical reconstruction of an area where 49 fish traps and 11 fish weirs were found during an excavation in a residual gully (van Zijverden 2002). It proved impossible to make a paleogeographical reconstruction of this landscape using conventional hand auger equipment (e.g. Palarczyk 1986; Gehasse 1990), but a combination of archived core descriptions and a DEM allowed for a surface reconstruction within an hour. Based on this experience, a research proposal to investigate the possibilities of this new technology for archaeological research was put together. In 2003, the project was funded by SENTER, an agency of the Dutch Ministry of Economic Affairs that coordinates projects to stimulate the application of new technologies by companies and research institutions.
High-resolution digital elevation models (usually based on airborne laser scanning) have been applied for archaeological research for more than ten years. In some regions, repeated coverage is becoming available, resulting in opportunities for the detection of changes which have occurred in-between the different surveys. However, while DTM change detection is in principle very simple, the practical application faces a number of challenges. These challenges include spatial resolution, horizontal and vertical accuracy as well as impacts of vegetation cover and data processing (e.g. strip adjustment and vegetation filtering). In addition to these challenges, the issue of comparing DTMs with DSMs arises when lidar-derived DTMs are supplemented with lower-cost and often more easily acquired photogrammetric DSMs. As a result, the seemingly straightforward approach to monitoring archaeological landscapes by analysing multi-temporal elevation data sets is limited with respect to the detectability of relief changes and the achievable accuracy of the quantification of such changes. Because of the ongoing developments in terms of spatial resolution and accuracy, it is usually the (older) baseline data set which limits the applicability and informative value of change detection approaches. Therefore, it is expected that large area monitoring schemes based on airborne lidar will only become operational once repeated coverage by high-quality surveys becomes available. However, results achieved in small test areas in Baden-Württemberg are promising despite the mentioned challenges.
Airborne LiDAR in Mountain Archaeology
The Oxford Handbook of Mountain Archaeology, 2024
Airborne LiDAR, or airborne Light Detection and Ranging, is a remote sensing technique that measures, among other things, the terrain elevation. In the past two decades, it has become an indispensable component of landscape archaeology, especially for archaeological prospection. However, it is still infrequently used in mountain archaeology. This is especially true in the high mountains, where technical challenges make its use difficult. We can anticipate more successful applications in the future due to the ever-improving quality of data. At present, the greatest untapped potential of LiDAR data for mountain archaeology, we argue, lies in "deep" interpretation or analysis of archaeological features in their landscape context. This approach is illustrated by the case study Vodotočnik (Slovenia). We used this high mountain pasture to test the hypothesis for site location choice, which was put forward by experienced mountain archaeologists. Based on the results of six distinct geomorphometric analyses we reinterpreted the site and demonstrated the benefits of LiDAR data for modelling landscape context at the scale of individual buildings and activity areas.
Construction of Digital Elevation Models for Archaeological Applications
Practical Applications of GIS for Archaeologists: A Predictive Modelling Toolkit, 2000
The use of interpolation in archaeology is becoming common. As archaeologists incorporate geographic information systems (GIS) and computer mapping programs into their research, questions of interpolation become fundamental considerations in the representation and manipulation of topographic data. To date, however, few archaeologists have dealt with these questions. Uncritical use of interpolation algorithms can result in unrealistic representations of the landscape in a mapping program or can result in an inaccurate digital elevation model (DEM) used in a GIS. This, in turn, can lead to an ineffective predictive model of site location. By carefully selecting an interpolation algorithm that is well suited to the data, statistical pitfalls and wasted effort can be avoided.
Visualization of lidar-derived relief models for detection of archaeological features
Journal of Archaeological Science, 2012
This paper presents visualisation techniques of high-resolution digital elevation models (DEMs) for visual detection of archaeological features. The methods commonly used in archaeology are reviewed and improvements are suggested. One straightforward technique that has so far not been used in archaeology e the shift method e is presented. The main purpose of this article is to compare and evaluate different visualisation methods. Two conclusions have been reached. Where a single method must be chosen e for printing or producing digital images for non-professionals e the use of sky view factor or slope gradient is endorsed, both presented in greyscale. Otherwise interpreters should choose different techniques on different terrain types: shift on flat terrain, sky view factor on mixed terrain, slope gradient on sloped terrain and sky view factor (preferably as a composite image with slope gradient) on rugged terrain.