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. The high ...costs of data collection are, for many applications in the earth sciences, exacerbated by the remoteness and inaccessibility of many field sites, rendering cheaper, more portable surveying platforms (i.e. terrestrial laser scanning or GPS) impractical. This paper outlines a revolutionary, low-cost, user-friendly photogrammetric technique for obtaining high-resolution datasets at a range of scales, termed ‘Structure-from-Motion’ (SfM). Traditional softcopy photogrammetric methods require the 3-D location and pose of the camera(s), or the 3-D location of ground control points to be known to facilitate scene triangulation and reconstruction. In contrast, the SfM method 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. A comprehensive introduction to the technique is presented, followed by an outline of the methods used to create high-resolution digital elevation models (DEMs) from extensive photosets obtained using a consumer-grade digital camera. As an initial appraisal of the technique, an SfM-derived DEM is compared directly with a similar model obtained using terrestrial laser scanning. This intercomparison reveals that decimetre-scale vertical accuracy can be achieved using SfM even for sites with complex topography and a range of land-covers. Example applications of SfM are presented for three contrasting landforms across a range of scales including; an exposed rocky coastal cliff; a breached moraine-dam complex; and a glacially-sculpted bedrock ridge. The SfM technique represents a major advancement in the field of photogrammetry for geoscience applications. Our results and experiences indicate SfM is an inexpensive, effective, and flexible approach to capturing complex topography.
► Structure-from-Motion represents an effective, low-cost topographic surveying tool. ► It requires little more than a consumer-grade digital camera and ground control. ► We benchmark the technique against data obtained from terrestrial laser scanning. ► 85.6% of the SfM data are accurate to within ±0.5m of the TLS data. ► Example applications are presented from Snowdonia, UK, and the Khumbu Himal, Nepal.
Light Detection and Ranging (LiDAR) and Structure from Motion (SfM) provide large amounts of digital data from which virtual outcrops can be created. The accuracy of these surface reconstructions is ...critical for quantitative structural analysis. Assessment of LiDAR and SfM methodologies suggest that SfM results are comparable to high data-density LiDAR on individual surfaces. The effect of chosen acquisition technique on the full outcrop and the efficacy on its virtual form for quantitative structural analysis and prediction beyond single bedding surfaces, however, is less certain. Here, we compare the accuracy of digital virtual outcrop analysis with traditional field data, for structural measurements and along-strike prediction of fold geometry from Stackpole syncline. In this case, the SfM virtual outcrop, derived from UAV imagery, yields better along-strike predictions and a more reliable geological model, in spite of lower accuracy surface reconstructions than LiDAR. This outcome is attributed to greater coverage by UAV and reliable reconstruction of a greater number of bedding planes than terrestrial LiDAR, which suffers from the effects of occlusion. Irrespective of the chosen acquisition technique, we find that workflows must incorporate careful survey planning, data processing and quality checking of derived data if virtual outcrops are to be used for robust structural analysis and along-strike prediction.
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•3 virtual outcrops of the same field structure compared for accuracy and coverage.•Derived from: terrestrial LiDAR, terrestrial images & UAV images.•Fidelity of virtual bedding surfaces tested against compass-clinometer measurements.•LiDAR-derived reconstructions of greatest accuracy, but lowest outcrop coverage.•Synoptic UAV positions sample entire outcrop, improving geological predictions.
This is a history of the Welsh in the centuries in which Wales acquired the shape it was to retain until the present day. In 350 what is now Wales was just one part of Roman Britain: contemporaries ...had no notion of Wales or the Welsh in the later-medieval or modern sense. The inhabitants of what is now Wales were just Britons; and, in the early middle ages, the Welsh remained one part of a larger group, the Britons, called Walas or Wealas by the English. The book thus includes the Britons of North Britain, of Cornwall, and of Brittany, although its main focus is the Britons of Wales. The period saw, first, the creation of an English people and, later, of an English state; relations with the Britons of Wales were an essential strand in these developments. For the Britons themselves relations with the English shaped the political and military side of their history; but, in the cultural and religious sphere relations with Ireland were usually more important. For relations of power the Britons of Wales looked east; in the intellectual and spiritual sphere they mostly looked west. The book is divided into four parts: the Post-Roman period, approximately 400–600; early Welsh society; relations with the English; and the religious organization and culture, both in Latin and the vernacular.
Imperial spaces takes two of the most influential minority groups of white settlers in the British Empire – the Irish and the Scots – and explores how they imagined themselves within the landscapes ...of its farthest reaches, the Australian colonies of Victoria and New South Wales. Using letters and diaries as well as records of collective activities such as committee meetings, parades and dinners, the book examines how the Irish and Scots built new identities as settlers in the unknown spaces of Empire. Utilizing critical geographical theories of ‘place’ as the site of memory and agency, it considers how Irish and Scots settlers grounded their sense of belonging in the imagined landscapes of south-east Australia. Emphasizing the complexity of colonial identity formation and the important ways in which this was spatially-constructed, Imperial Spaces challenges conventional understandings of the Irish and Scottish presence in Australia. The opening chapters locate the book’s themes and perspectives within a survey of the existing historical and geographical literature on empire and diaspora. These pay particular attention to the ‘new’ imperial history and to alternative transnational and ‘located’ understandings of diasporic consciousness. Subsequent chapters work within these frames and examine the constructions of place evinced by Irish and Scottish emigrants during the outward voyage and subsequent processes of pastoral and urban settlement, and in religious observance. Imperial spaces is relevant to academics and students interested in the history and geography of the British Empire, Australia, Ireland and Scotland.
Was migration from Victorian Cardiganshire simply a flight from rural poverty? This book relates the rate and timing of the outward movements from the county in the nineteenth century to the ...prevailing social and economic conditions. It provides insights into the motivations for and factors involved in migration; and using contemporary source material and computer-assisted analysis of census enumerators' books examines key dimensions of the communities at the major migrant destinations - Glamorgan, Carmarthenshire, London and Merseyside in Britain, and Ohio and Wisconsin, USA.
This book explores the representation of Wales and ‘Welshness’ in texts by French- (including Breton) and German-speaking travellers from 1780 to the present day. Since the emergence of the travel ...narrative as a popular source of information and entertainment in the mid-18th century, writing about Wales has often been embedded and hidden in accounts of travel to ‘England’. This book locates and presents these largely forgotten texts and broadens perspectives to encompass European perceptions. Works uncovered for the first time include travelogues, private correspondences, travel diaries, articles and blogs which have Wales or Welsh culture as their focus. The ‘travellers’ analysed in this volume include those travelling for the purpose of leisure, scholarship or commerce as well as exiles and refugees. By focusing on Wales, a minoritized nation at the geographical periphery of Europe, the authors are able to problematize notions of hegemony and identity, relating to both the places encountered (the ‘travellee’ culture) and the places of origin (the travellers’ cultures). This book thereby makes an original contribution to studies in travel writing and provides an important case study of a culture often minoritized in the field, but that nevertheless provides a telling illustration of the dynamics of intercultural relations and representation.
Secret sins Davies, Russell; Davies, Russell
2012., 20121115, 2012, 2012-11-01, 2012-11-15
eBook
Sleepy rustic Carmarthenshire was secretly a hotbed of debauchery, violence and drunkenness according to Russell Davies in a new edition of his very successful book, ‘Secret Sins’. Behind the facade ...of idyllic rural life, there was a twilight world of mental illness, suicide, crime, vicious assaults, infanticide, cruelty and other assorted acts of depravity. This almost anecdotal historical study is often funny, sometimes disturbing, always revealing.
Language Policy in Business: Discourse, ideology and practice provides a critical sociolinguistic and discursive understanding of language policy in a minority language context, focusing on ...Welsh-English bilingualism in private sector businesses in Wales.
This latest volume in the Penal Theory and Penal Ethics series addresses one of the oldest and most contested questions in the field of criminal sentencing: should an offender's previous convictions ...affect the sentence? This question provokes a series of others: Is it possible to justify a discount for first offenders within a retributive sentencing framework? How should previous convictions enter into the sentencing equation? At what point should prior misconduct cease to count for the purposes of fresh sentencing? Should similar previous convictions count more than convictions unrelated to the current offence? Statutory sentencing regimes around the world incorporate provisions which mandate harsher treatment of repeat offenders. Although there is an extensive literature on the definition and use of criminal history information, the emphasis here, as befits a volume in the series, is on the theoretical and normative aspects of considering previous convictions at sentencing. Several authors explore the theory underlying the practice of mitigating the punishments for first offenders, while others put forth arguments for enhancing sentences for recidivists. The practice of sentencing repeat offenders in two jurisdictions (England and Wales, and Sweden) is also examined in detail.
The hanged man Bartlett, Robert
2013., 20130717, 2013, 2004, 2013-07-17
eBook
Seven hundred years ago, executioners led a Welsh rebel named William Cragh to a wintry hill to be hanged. They placed a noose around his neck, dropped him from the gallows, and later pronounced him ...dead. But was he dead? While no less than nine eyewitnesses attested to his demise, Cragh later proved to be very much alive, his resurrection attributed to the saintly entreaties of the defunct Bishop Thomas de Cantilupe. The Hanged Man tells the story of this putative miracle--why it happened, what it meant, and how we know about it. The nine eyewitness accounts live on in the transcripts of de Cantilupe's canonization hearings, and these previously unexamined documents contribute not only to an enthralling mystery, but to an unprecedented glimpse into the day-to-day workings of medieval society. While unraveling the haunting tale of the hanged man, Robert Bartlett leads us deeply into the world of lords, rebels, churchmen, papal inquisitors, and other individuals living at the time of conflict and conquest in Wales. In the process, he reconstructs voices that others have failed to find. We hear from the lady of the castle where the hanged man was imprisoned, the laborer who watched the execution, the French bishop charged with investigating the case, and scores of other members of the medieval citizenry. Brimming with the intrigue of a detective novel, The Hanged Man will appeal to both scholars of medieval history and general readers alike.
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