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| Titel |
Comparing and combining terrestrial laser scanning with ground-and UAV-based imaging for national-level assessment of soil erosion |
| VerfasserIn |
Gareth McShane, Mike R. James, John Quinton, Karen Anderson, Leon DeBell, Martin Evans, Luke Farrow, Miriam Glendell, Lee Jones, Matthew Kirkham, Murray Lark, Barry Rawlins, Jane Rickson, Tim Quine, Andy Wetherelt, Richard Brazier |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093198
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| Publikation (Nr.) |
 EGU/EGU2014-7709.pdf |
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| Zusammenfassung |
| 3D topographic or surface models are increasingly being utilised for a wide range of
applications and are established tools in geomorphological research. In this pilot study ‘a cost
effective framework for monitoring soil erosion in England and Wales’, funded by the UK
Department for Environment, Food and Rural Affairs (Defra), we compare methods of
collecting topographic measurements via remote sensing for detailed studies of dynamic
processes such as erosion and mass movement. The techniques assessed are terrestrial laser
scanning (TLS), and unmanned aerial vehicle (UAV) photography and ground-based
photography, processed using structure-from-motion (SfM) 3D reconstruction software. The
methods will be applied in regions of different land use, including arable and horticultural,
upland and semi natural habitats, and grassland, to quantify visible erosion pathways at
the site scale. Volumetric estimates of soil loss will be quantified using the digital
surface models (DSMs) provided by each technique and a modelled pre-erosion
surface.
Visible erosion and severity will be independently established through each technique,
with their results compared and combined effectiveness assessed. A fixed delta-wing UAV
(QuestUAV, http://www.questuav.com/) captures photos from a range of altitudes and angles
over the study area, with automated SfM-based processing enabling rapid orthophoto
production to support ground-based data acquisition. At sites with suitable scale erosion
features, UAV data will also provide a DSM for volume loss measurement. Terrestrial laser
scanning will provide detailed, accurate, high density measurements of the ground surface
over long (100s m) distances. Ground-based photography is anticipated to be most useful
for characterising small and difficult to view features. By using a consumer-grade
digital camera and an SfM-based approach (using Agisoft Photoscan version 1.0.0,
http://www.agisoft.ru/products/photoscan/), less expertise and fewer control measurements
are required compared with traditional photogrammetry, and image processing is
automated. Differential GPS data will be used to geo-reference the models to facilitate
comparison.
The relative advantages, limitations and cost-effectiveness of each approach
will be established, and which technique, or combination of techniques, is most
appropriate to monitor, model and estimate soil erosion at the national scale, determined. |
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