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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 uncertain as to the errors associated with each choice and, perhaps most fundamentally, the processes actually taking place as part of the SfM-MVS workflow. This paper details the typical workflow applied by SfM-MVS software packages, reviews practical details of implementing SfM-MVS, combines existing validation studies to assess practically achievable data quality and reviews the range of applications of SfM-MVS in physical geography. The flexibility of the SfM-MVS approach complicates attempts to validate SfM-MVS robustly as each individual validation study will use a different approach (e.g. platform, camera, georeferencing method, etc.). We highlight the need for greater transparency in SfM-MVS processing and enhanced ability to adjust parameters that determine survey quality. Looking forwards, future prospects of SfM-MVS in physical geography are identified through discussion of more recent developments in the fields of image analysis and computer vision. [ABSTRACT FROM AUTHOR]

Understanding the changing mass balance and surface dynamics of the Earth's major ice sheets in Greenland and Antarctica is of fundamental importance for accurate predictions of future sea-level rise. In this review, the remote sensing data sources available to ice-sheet studies are considered and the range of information that can be gained from remote sensing is examined. The review demonstrates that the integration of a range of remote sensing data sets can provide information on ice-sheet dynamics and volume changes, melt patterns and formation and drainage of supra- and subglacial lakes. Such data are highly complementary to field investigations by providing a regional-scale, synoptic perspective. The review concludes that emerging remote sensing techniques such as SAR interferometry, feature tracking, scatterometry, altimetry and gravimetry provide vital information without which an understanding of ice sheets would be far less advanced. It also concludes that there remain several key challenges for remote sensing, in particular relating to the observation of rapid dynamical changes that are characteristic of contemporary ice-sheet response to continued climatic warming. [ABSTRACT FROM AUTHOR]

Remote sensing studies have shown that glaciers and their proximal environments exhibit unique temporal, spatial and spectral characteristics that can be analysed to better quantify glacial hazard potential. In this review, the optical remote sensing data sources available to glacial hazard assessors are considered and the range of information on glacial environments that can be derived is analysed. The review shows that the integration of a variety of data sources can provide geoscientists with information regarding glacial lakes and lake development, glacier dynamics, avalanche sources and ice-marginal fluctuations. Such data can be used to complement and, in many cases, improve field-based glacial hazard assessments. The review concludes that aerial photography still remains the main source of data for measuring a number of glacier characteristics, but that fine to moderate spatial resolution satellite sensors (e.g., ASTER, SPOT 5 HRVIR, Landsat ETM+) also provide useful information that can be used to support the assessment of hazards in high-mountain glacierized terrain. [ABSTRACT FROM AUTHOR]