Author
Matthew J. Westoby
Other affiliations: Aberystwyth University
Bio: Matthew J. Westoby is an academic researcher from Northumbria University. The author has contributed to research in topics: Glacier & Photogrammetry. The author has an hindex of 16, co-authored 32 publications receiving 2997 citations. Previous affiliations of Matthew J. Westoby include Aberystwyth University.
Topics: Glacier, Photogrammetry, Moraine, Ice sheet, Antarctic ice sheet
Papers
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TL;DR: The Structure-from-Motion (SfM) method as mentioned in this paper solves the camera pose and scene geometry simultaneously and automatically, using a highly redundant bundle adjustment based on matching features in multiple overlapping, offset images.
2,901 citations
TL;DR: In this article, a review of the available approaches available to model the individual stages, or components, of a glacial lake outburst flood (GLOF) event is introduced and discussed.
211 citations
University of Calgary1, Cooperative Institute for Research in Environmental Sciences2, Swiss Federal Institute for Forest, Snow and Landscape Research3, ETH Zurich4, University of Washington5, University of Zurich6, University of Potsdam7, United States Geological Survey8, University of Minnesota9, University of Natural Resources and Life Sciences, Vienna10, University of Graz11, University of Toulouse12, University of Utah13, Heidelberg University14, University of Geneva15, University of Leeds16, Simon Fraser University17, Newcastle University18, University of Dayton19, University of Oslo20, Planetary Science Institute21, University of Alberta22, University of Grenoble23, University of Sheffield24, Indian Institute of Technology Indore25, University of Dundee26, UNESCO27, Jawaharlal Nehru University28, Stockholm International Water Institute29, University of British Columbia30, University of Exeter31, Kathmandu32, Wadia Institute of Himalayan Geology33, University of Kashmir34, University of Delhi35, Utrecht University36, International Centre for Integrated Mountain Development37, University of Chile38, Northumbria University39
TL;DR: In this paper, an analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27x106 m3 of rock and glacier ice collapsed from the steep north face of Ronti Peak.
Abstract: On 7 Feb 2021, a catastrophic mass flow descended the Ronti Gad, Rishiganga, and Dhauliganga valleys in Chamoli, Uttarakhand, India, causing widespread devastation and severely damaging two hydropower projects. Over 200 people were killed or are missing. Our analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27x106 m3 of rock and glacier ice collapsed from the steep north face of Ronti Peak. The rock and ice avalanche rapidly transformed into an extraordinarily large and mobile debris flow that transported boulders >20 m in diameter, and scoured the valley walls up to 220 m above the valley floor. The intersection of the hazard cascade with downvalley infrastructure resulted in a disaster, which highlights key questions about adequate monitoring and sustainable development in the Himalaya as well as other remote, high-mountain environments.
201 citations
73 citations
TL;DR: In this article, SfM-MVS methods were used to develop 3D RGB and thermal point clouds of the two sites with point densities of 35,245 and 776 points per m 2, respectively.
65 citations
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01 Dec 2013
TL;DR: This paper found that the most intensive glacier shrinkage is in the Himalayan region, whereas glacial retreat in the Pamir Plateau region is less apparent, due to changes in atmospheric circulations and precipitation patterns.
Abstract: Glacial melting in the Tibetan Plateau affects the water resources of millions of people. This study finds that—partly owing to changes in atmospheric circulations and precipitation patterns—the most intensive glacier shrinkage is in the Himalayan region, whereas glacial retreat in the Pamir Plateau region is less apparent.
1,599 citations
TL;DR: In this article, a Structure from Motion (SfM) workflow was applied to derive a 3D model of a landslide in southeast Tasmania from multi-view UAV photography and the geometric accuracy of the model and resulting DEMs and orthophoto mosaics was tested with ground control points coordinated with geodetic GPS receivers.
Abstract: In this study, we present a flexible, cost-effective, and accurate method to monitor landslides using a small unmanned aerial vehicle (UAV) to collect aerial photography. In the first part, we apply a Structure from Motion (SfM) workflow to derive a 3D model of a landslide in southeast Tasmania from multi-view UAV photography. The geometric accuracy of the 3D model and resulting DEMs and orthophoto mosaics was tested with ground control points coordinated with geodetic GPS receivers. A horizontal accuracy of 7 cm and vertical accuracy of 6 cm was achieved. In the second part, two DEMs and orthophoto mosaics acquired on 16 July 2011 and 10 November 2011 were compared to study landslide dynamics. The COSI-Corr image correlation technique was evaluated to quantify and map terrain displacements. The magnitude and direction of the displacement vectors derived from correlating two hillshaded DEM layers corresponded to a visual interpretation of landslide change. Results show that the algorithm can accurately map displacements of the toes, chunks of soil, and vegetation patches on top of the landslide, but is not capable of mapping the retreat of the main scarp. The conclusion is that UAV-based imagery in combination with 3D scene reconstruction and image correlation algorithms provide flexible and effective tools to map and monitor landslide dynamics.
606 citations
TL;DR: In this paper, a detailed error analysis of sub-meter resolution terrain models of two contiguous reaches (1.6 and 1.7 km long) of the braided Ahuriri River, New Zealand, generated using Structure-from-Motion (SfM) is presented.
573 citations
TL;DR: The typical workflow applied by SfM-MVS software packages is detailed, practical details of implementing S fM- MVS are reviewed, existing validation studies to assess practically achievable data quality are combined, and the range of applications in physical geography are reviewed.
Abstract: Accurate, precise and rapid acquisition of topographic data is fundamental to many sub-disciplines of physical geography. Technological developments over the past few decades have made fully distributed data sets of centimetric resolution and accuracy commonplace, yet the emergence of Structure from Motion (SfM) with Multi-View Stereo (MVS) in recent years has revolutionised three-dimensional topographic surveys in physical geography by democratising data collection and processing. SfM-MVS originates from the fields of computer vision and photogrammetry, requires minimal expensive equipment or specialist expertise and, under certain conditions, can produce point clouds of comparable quality to existing survey methods (e.g. Terrestrial Laser Scanning). Consequently, applications of SfM-MVS in physical geography have multiplied rapidly. There are many practical options available to physical geographers when planning a SfM-MVS survey (e.g. platforms, cameras, software), yet, many SfM-MVS end-users are uncert...
565 citations
TL;DR: In this paper, the use of modern 3D photo-based surface reconstruction techniques for high fidelity surveys of trenches, rock exposures and hand specimens is discussed, highlighting their potential for paleoseismology and structural geology.
548 citations