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| Titel |
Comparing terrestrial laser scanning with ground and UAV-based imaging for national-level assessment of upland soil erosion |
| VerfasserIn |
Gareth McShane, Luke Farrow, David Morgan, Miriam Glendell, Mike James, John Quinton, Martin Evans, Karen Anderson, Barry Rawlins, Timothy Quine, Leon DeBell, Pia Benaud, Lee Jones, Matthew Kirkham, Murray Lark, Jane Rickson, Richard Brazier |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111274
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| Publikation (Nr.) |
 EGU/EGU2015-11376.pdf |
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| Zusammenfassung |
| Quantifying soil loss through erosion processes at a high resolution can be a time consuming
and costly undertaking. 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 for collecting suitable topographic measurements
via remote sensing. The aim is to enable efficient but detailed site-scale studies of erosion
forms in inaccessible UK upland environments, to quantify 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, both processed using structure-from-motion (SfM) 3D reconstruction
software.
Compared to other established techniques, such as expensive TLS, SfM offers a potentially
low-cost alternative for the reconstruction of 3D high-resolution micro-topographic models
from photographs taken with consumer grade cameras. However, whilst an increasing
number of research papers examine the relative merits of these novel versus more
established survey techniques, no study to date has compared both ground-based and
aerial SfM photogrammetry with TLS scanning across a range of scales (from m2 to
16ha). The evaluation of these novel low cost techniques is particularly relevant
in upland landscapes, where the remoteness and inaccessibility of field sites may
render some of the more established survey techniques impractical. Volumetric
estimates of soil loss are quantified using the digital surface models (DSMs) derived
from the data from each technique and subtracted from a modelled pre-erosion
surface.
The results from each technique are compared.
The UAV was able to capture information over a wide area, a range of altitudes
and angles over the study area. Combined with automated SfM-based processing,
this technique was able to produce rapid orthophotos to support ground-based
data acquisition, as well as a DSM for volume loss measurement in larger
features. However, the DSM of erosion features lacked the detail of those
captured using the ground-based methods.
Terrestrial laser scanning provided detailed, accurate, high density measurements
of the ground surface over long (100s m) distances, but size and weight of the
instrument made it difficult to use in mountainous environments. In addition,
deriving a reliable bare-earth digital terrain model (DTM) from TLS was at times
problematic due to the presence of tall shrubby vegetation.
Ground-based photography produced comparable data sets to terrestrial laser
scanning and was the most useful for characterising small and difficult to view
features.
The relative advantages, limitations and cost-effectiveness of each approach at 5 upland sites
across the UK are discussed. |
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