Ending the Cinderella Status of Terraces and Lynchets in Europe

2020 ◽  
Author(s):  
Daniel Fallu ◽  
Tony Brown ◽  
Kevin Walsh ◽  
Sara Cucchiaro ◽  
Paolo Tarolli ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Holistic Approach ◽  
Theoretical Background ◽  
New Techniques ◽  
Erosion Rates ◽  
Digital Terrain ◽  
Terrain Models ◽  
Calcium Oxalates ◽  
Demographic Fluctuations

<p>Terraces and lynchets are not only ubiquitous worldwide and within Europe but can provide increasingly important Ecosystem Services (ESs), which may be able to mitigate aspects of climate change. They are also probably a major cause of non-linearity between climate and erosion rates in agricultural systems as noted from alluvial and colluvial studies. In this paper we review the theoretical background of terraces and lynchets, present a modified classification, and show how new techniques are transforming the study of these widespread and often ancient anthropogenic landforms. Indeed the problems of dating terraces and also the time-consuming nature and costly surveys has held back the archaeological study of terraces until now. The applicable suite of techniques available now includes the creation of Digital Terrain Models (DTMs) from Structure from Motion (SfM) photogrammetry, Airborne and Terrestrial Laser Scanning (ALS-TLS); the use of OSL and pOSL, pXRF, FTIR, phytoliths, calcium oxalates from plants and potentially sedaDNA. Examples will be drawn from a recently started ERC project (TerrACE; ERC-2017-ADG: 787790, 2018-2023; https://www.terrace.no/) which is working at over 10 sites in Europe ranging from Norway to Greece.</p><p>This paper explains the development of a new holistic approach to terrace archaeology driven by a modern conceptualisation of human-landscape relationships, and facilitated by new scientific developments. We explain the rationale for our choice of case study areas, for example, the range of bio-climatic zones. In addition, this multi-regional approach allows us to address contingent regional and local historical/socioeconomic processes; from demographic fluctuations to the development of specific forms of agricultural techniques. Examples of DTM creation, field analyses and selected results will be given from Martleburg in Belgium and sites in Italy. We will then move on to explain how this combination of a comprehensive suite of modern field and laboratory methods and an interpretive strategy informed by the environmental humanities will yield exciting and groundbreaking results.</p>

scholarly journals Accuracy Assessment of Point Clouds from LiDAR and Dense Image Matching Acquired Using the UAV Platform for DTM Creation

2018 ◽  
Vol 7 (9) ◽  
pp. 342 ◽  
Author(s):  
Adam Salach ◽  
Krzysztof Bakuła ◽  
Magdalena Pilarska ◽  
Wojciech Ostrowski ◽  
Konrad Górski ◽  
...  
Keyword(s):  
Land Cover ◽  
Laser Scanning ◽  
Point Clouds ◽  
Data Sources ◽  
Digital Terrain Models ◽  
Vegetation Height ◽  
Digital Terrain ◽  
Terrain Models ◽  
Airborne Laser ◽  
Vertical Accuracy

In this paper, the results of an experiment about the vertical accuracy of generated digital terrain models were assessed. The created models were based on two techniques: LiDAR and photogrammetry. The data were acquired using an ultralight laser scanner, which was dedicated to Unmanned Aerial Vehicle (UAV) platforms that provide very dense point clouds (180 points per square meter), and an RGB digital camera that collects data at very high resolution (a ground sampling distance of 2 cm). The vertical error of the digital terrain models (DTMs) was evaluated based on the surveying data measured in the field and compared to airborne laser scanning collected with a manned plane. The data were acquired in summer during a corridor flight mission over levees and their surroundings, where various types of land cover were observed. The experiment results showed unequivocally, that the terrain models obtained using LiDAR technology were more accurate. An attempt to assess the accuracy and possibilities of penetration of the point cloud from the image-based approach, whilst referring to various types of land cover, was conducted based on Real Time Kinematic Global Navigation Satellite System (GNSS-RTK) measurements and was compared to archival airborne laser scanning data. The vertical accuracy of DTM was evaluated for uncovered and vegetation areas separately, providing information about the influence of the vegetation height on the results of the bare ground extraction and DTM generation. In uncovered and low vegetation areas (0–20 cm), the vertical accuracies of digital terrain models generated from different data sources were quite similar: for the UAV Laser Scanning (ULS) data, the RMSE was 0.11 m, and for the image-based data collected using the UAV platform, it was 0.14 m, whereas for medium vegetation (higher than 60 cm), the RMSE from these two data sources were 0.11 m and 0.36 m, respectively. A decrease in the accuracy of 0.10 m, for every 20 cm of vegetation height, was observed for photogrammetric data; and such a dependency was not noticed in the case of models created from the ULS data.

scholarly journals Detection of earthflow dynamics using medium-resolution digital terrain models: Diachronic perspective of the Jovac earthflow, Southern Serbia

2021 ◽  
Vol 61 (2) ◽  
pp. 187-206
Author(s):  
Marko Milošević ◽  
Dragoljub Štrbac ◽  
Jelena Ćalić ◽  
Milan Radovanović
Keyword(s):  
Digital Terrain Models ◽  
Digital Terrain ◽  
Terrain Models ◽  
Landslide Volume ◽  
Medium Resolution ◽  
Before And After ◽  
Movement Mechanism ◽  
Research Procedure ◽  
Definition Of

The paper presents and discusses the landslide research procedure related to the topography before and after its occurrence, using the comparative analysis of two medium-resolution digital terrain models. The case study is the Jovac mega-landslide—the largest landslide to occur in Serbia in the last 100 years, active for three days in February 1977. The indicators used to determine the volume and movement mechanism were the spatial distribution of elevation differences within the two digital terrain models (DTM), and the analysis of geomorphological features before the landslide. The obtained elevation differences allowed the definition of the approximate landslide volume: 11.6 × 106 m3. All the data obtained indicate that the movement mechanism falls into the category of earthflow.

scholarly journals ENHANCING THE RESOLUTION OF URBAN DIGITAL TERRAIN MODELS USING MOBILE MAPPING SYSTEMS

2018 ◽  
Vol IV-4/W6 ◽  
pp. 11-18
Author(s):  
Y. Feng ◽  
C. Brenner ◽  
M. Sester
Keyword(s):  
Urban Areas ◽  
Laser Scanning ◽  
Overland Flow ◽  
Point Clouds ◽  
Digital Terrain Models ◽  
Mobile Mapping ◽  
Flow Modelling ◽  
Digital Terrain ◽  
Terrain Models ◽  
Mapping Techniques

<p><strong>Abstract.</strong> Digital Terrain Models (DTMs) are essential surveying products for terrain based analyses, especially for overland flow modelling. Nowadays, many high resolution DTM products are generated by Airborne Laser Scanning (ALS). However, DTMs with even higher resolution are of great interest for a more precise overland flow modelling in urban areas. With the help of mobile mapping techniques, we can obtain much denser measurements of the ground in the vicinity of roads. In this research, a study area in Hannover, Germany was measured by a mobile mapping system. Point clouds from 485 scan strips were aligned and a DTM was extracted. In order to achieve a product with completeness, this mobile mapping produced DTM was then merged and adapted with a DTM product with 0.5<span class="thinspace"></span>m resolution from a mapping agency. Systematic evaluations have been conducted with respect to the height accuracy of the DTM products. The results show that the final DTM product achieved a higher resolution (0.1<span class="thinspace"></span>m) near the roads while essentially maintaining its height accuracy.</p>

scholarly journals FILTERING PHOTOGRAMMETRIC POINT CLOUDS USING STANDARD LIDAR FILTERS TOWARDS DTM GENERATION

2018 ◽  
Vol IV-2 ◽  
pp. 319-326 ◽  
Author(s):  
Z. Zhang ◽  
M. Gerke ◽  
G. Vosselman ◽  
M. Y. Yang
Keyword(s):  
Laser Scanning ◽  
Type I Error ◽  
Research Question ◽  
Random Noise ◽  
Point Clouds ◽  
Type I ◽  
Low Contrast ◽  
Digital Terrain ◽  
Terrain Models ◽  
Dense Matching

Digital Terrain Models (DTMs) can be generated from point clouds acquired by laser scanning or photogrammetric dense matching. During the last two decades, much effort has been paid to developing robust filtering algorithms for the airborne laser scanning (ALS) data. With the point cloud quality from dense image matching (DIM) getting better and better, the research question that arises is whether those standard Lidar filters can be used to filter photogrammetric point clouds as well. Experiments are implemented to filter two dense matching point clouds with different noise levels. Results show that the standard Lidar filter is robust to random noise. However, artefacts and blunders in the DIM points often appear due to low contrast or poor texture in the images. Filtering will be erroneous in these locations. Filtering the DIM points pre-processed by a ranking filter will bring higher Type II error (i.e. non-ground points actually labelled as ground points) but much lower Type I error (i.e. bare ground points labelled as non-ground points). Finally, the potential DTM accuracy that can be achieved by DIM points is evaluated. Two DIM point clouds derived by Pix4Dmapper and SURE are compared. On grassland dense matching generates points higher than the true terrain surface, which will result in incorrectly elevated DTMs. The application of the ranking filter leads to a reduced bias in the DTM height, but a slightly increased noise level.

scholarly journals A 2D hydrodynamic-sedimentological model for gravel bed rivers. Part II, Case study: the Brenta River in Italy

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Gabriel Kaless ◽  
Johnny Moretto ◽  
Fabio Delai ◽  
Luca Mao ◽  
Mario A. Lenzi
Keyword(s):  
Low Frequency ◽  
Channel Changes ◽  
Gravel Bed ◽  
Digital Terrain ◽  
Terrain Models ◽  
Extensive Field ◽  
Subsurface Material ◽  
Sediment Flow ◽  
Imaging Detection

A 2D depth average model has been used to simulate water and sediment flow in the Brenta River so as to interpret channel changes and to assess model predictive capabilities. The Brenta River is a gravel bed river located in Northern Italy. The study reach is 1400 long and has a mean slope of 0.0056. High resolution digital terrain models has been produced combining laser imaging detection and ranging data with colour bathymetry techniques. Extensive field sedimentological surveys have been also carried out for surface and subsurface material. The data were loaded in the model and the passage of a high intense flood (R.I. &gt; 9 years) was simulated. The model was run under the hypothesis of a substantial equilibrium between sediment input and transport capacity. In this way, the model results were considered as a reference condition, and the potential trend of the reach was assessed. Low-frequency floods (R.I. » 1.5 years) are expected to produce negligible changes in the channel while high floods may focalize erosion on banks instead than on channel bed. Furthermore, the model predicts well the location of erosion and siltation areas and the results promote its application to other reaches of the Brenta River in order to assess their stability and medium-term evolution.

scholarly journals A Holistic Approach in Re-Mining Old Tailings Deposits for the Supply of Critical-Metals: A Portuguese Case Study

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 638 ◽  
Author(s):  
Figueiredo ◽  
Vila ◽  
Fiúza ◽  
Góis ◽  
Futuro ◽  
...  
Keyword(s):  
Mine Waste ◽  
Holistic Approach ◽  
Processing Plant ◽  
Environmental Aspects ◽  
Critical Metals ◽  
Field Sample ◽  
New Techniques ◽  
Demand Growth ◽  
Panasqueira Mine

Demand growth for metallic minerals has been faced with the need for new techniques and improving technologies for all mining life-cycle operations. Nowadays, the exploitation of old tailings and mine-waste facilities could be a solution to this demand, with economic and environmental advantages. The Panasqueira Mine has been operating for more than a century, extracting tungsten and tin ore. Its first processing plant, “Rio”, was located near the Zêrere river, where mineral-processing residues were deposited on the top hillside on the margin of this river in the Cabeço do Pião tailings dam. The lack of maintenance and monitoring of this enormous structure in the last twenty years represents a high risk to the environment and the population of the surrounding region. A field-sample campaign allowed the collection of data, and resulted from laboratory tests to use regression optimization. Re-mining the tailings by hydrometallurgical methods was considered to satisfy the two conditions of metal demand and environmental risk. The metal content in Cabeço do Pião was shown be enough for environmental restoration. The re-mining solution was studied, taking into account the technical, economic, social, and environmental aspects.

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