Innovative analysis and use of high‐resolution DTMs for quantitative interrogation of Earth‐surface processes

Abstract

This is the era of digital landscapes; the widespread availability of powerful sensing technologies has revolutionized the way it is possible to interrogate landscapes in order to understand the processes sculpting them. Vastly greater areas have now been acquired at ‘high resolution’: currently tens of metres globally to millimetric precision and accuracy locally. This permits geomorphic features to be visualized and analysed across the scales at which Earth‐surface processes operate. Especially exciting is the capturing of process dynamics in repeated surveying, which will only become more important with low‐cost accessible data generation through techniques such as Structure from Motion (SfM). But the key challenge remains; to interpret high resolution Digital Terrain Models (DTMs), particularly by extracting geomorphic features in robust and objective ways and then linking the observed features to the underlying physical processes. In response to the new data and challenges, recent years have seen improved processing of raw data into DTMs, development of data fusion techniques, novel quantitative analysis of topographic data, and innovative geomorphological mapping. The twelve papers collected in this volume sample this progress in interrogating Earth‐surface processes through the analysis of DTMs. They cover a wide range of disciplines and spatio‐temporal scales, from landslide prone landscapes, to agriculturally modified regions, to mountainous landscapes, and coastal zones. They all, however, showcase the quantitative exploitation of information contained in high‐resolution topographic data that we believe will underpin the improvement of our understanding of many elements of Earth‐surface processes. Most of the papers introduced here were first presented in a conference session at the European Geosciences Union General Assembly in 2011. Copyright © 2014 John Wiley & Sons, Ltd.

UAS‐based remote sensing of fluvial change following an extreme flood event

“…With the operational flexibility associated with UAS surveys and the rapid proliferation of the technology, multi‐temporal datasets capturing geomorphic processes in three dimensions will become more common (e.g. Passalacqua et al ., ; Tarolli, ). The case study of the Elbow River shows potential strengths and limitations of how such datasets and modeling can contribute to the wider understanding of fluvial processes at intermediate scales.…”

“…In fluvial settings, UAS‐based remote sensing has proven to be an efficient, flexible, and reliable method of collecting high‐resolution topographic data and imagery (Lejot et al ., ; Flener et al ., ; Tamminga et al ., ; Woodget et al ., ), with vertical elevation errors of less than 10 cm and image resolution on the scale of 5 cm/pixel (James & Robson, ). Such continuous high‐quality data facilitate investigation of aspects of earth surface processes that were previously difficult or impossible to measure (Fonstad and Marcus, ; Passalacqua et al ., ). By combining UAS surveys bracketing a flood event with hydrodynamic models, we aim to address three related questions: (i) What are the reach‐scale geomorphic effects of a large flood event?…”

Bank erosion in agricultural drainage networks: new challenges from structure‐from‐motion photogrammetry for post‐event analysis

“…The SDE of the DEM TLS was estimated to be within ± 0.1 m. For the purposes of this work, we based all our analyses on the final DEMs (as in Wechsler, 2007;Calligaro et al, 2013;Bangen et al, 2014;Javernick et al, 2014;Ouédraogo et al, 2014;Tarolli et al, 2015), and we focused on only the error related to the DEM itself, rather than that in the point cloud. Jones et al, 2007;Notebaert et al, 2009;Passalacqua et al, 2014;Sofia et al, 2014aSofia et al, , 2014bTarolli, 2014;Tarolli et al, 2015), the DEM TLS was considered as a benchmark to compare DEMs obtained using the SfM methodology (as in Micheletti et al, 2014). Localization of the study area along the agricultural channel Scolo Orsaro, within the Bacchiglione Land Reclamation Consortium (BLRC) in the Veneto region, Italy.…”

Open-pit mining geomorphic feature characterisation

“…Light detection and ranging (LiDAR) technology (Slatton et al, 2007;Roering et al, 2013) and, more recently, Structure from Motion (SfM) photogrammetry (Westoby et al, 2012;Fonstad et al, 2013;Javernick et al, 2014;Micheletti et al, 2014;Prosdocimi et al, 2015) provide high resolution topographic data with notable advantages over traditional survey techniques. A valuable characteristic of these technologies is their capability to produce sub-meter resolution digital terrain models (DTMs), and high-quality land coverage information (digital surface models, DSMs) over large areas (Tarolli et al, 2009;Pirotti et al, 2012;Passalacqua et al, 2014). LiDAR high-resolution topographic surveying is traditionally associated with high capital and logistical costs, so that data acquisition is often passed on to specialist third party organisations (Westoby et al, 2012).…”