Visual Techniques for Geological Fieldwork Using Mobile Devices

Visual techniques in general and 3D visualisation in particular have seen considerable adoption within the last 30 years in the geosciences and geology. Techniques such as volume visualisation, for analysing subsurface processes, and photo-coloured LiDAR point-based rendering, to digitally explore rock exposures at the earth’s surface, were applied within geology as one of the first adopting branches of science. A large amount of digital, geological surface- and volume data is nowadays available to desktop-based workflows for geological applications such as hydrocarbon reservoir exploration, groundwater modelling, CO2 sequestration and, in the future, geothermal energy planning. On the other hand, the analysis and data collection during fieldwork has yet to embrace this ”digital revolution”: sedimentary logs, geological maps and stratigraphic sketches are still captured in each geologist’s individual fieldbook, and physical rocks samples are still transported to the lab for subsequent analysis. Is this still necessary, or are there extended digital means of data collection and exploration in the field ? Are modern digital interpretation techniques accurate and intuitive enough to relevantly support fieldwork in geology and other geoscience disciplines ? This dissertation aims to address these questions and, by doing so, close the technological gap between geological fieldwork and office workflows in geology. The emergence of mobile devices and their vast array of physical sensors, combined with touch-based user interfaces, high-resolution screens and digital cameras provide a possible digital platform that can be used by field geologists. Their ubiquitous availability increases the chances to adopt digital workflows in the field without additional, expensive equipment. The use of 3D data on mobile devices in the field is furthered by the availability of 3D digital outcrop models and the increasing ease of their acquisition. This dissertation assesses the prospects of adopting 3D visual techniques and mobile devices within field geology. The research of this dissertation uses previously acquired and processed digital outcrop models in the form of textured surfaces from optical remote sensing and photogrammetry. The scientific papers in this thesis present visual techniques and algorithms to map outcrop photographs in the field directly onto the surface models. Automatic mapping allows the projection of photo interpretations of stratigraphy and sedimentary facies on the 3D textured surface while providing the domain expert with simple-touse, intuitive tools for the photo interpretation itself. The developed visual approach, combining insight from all across the computer sciences dealing with visual information, merits into the mobile device Geological Registration and Interpretation Toolset (GRIT) app, which is assessed on an outcrop analogue study of the Saltwick Formation exposed at Whitby, North Yorkshire, UK. Although being applicable to a diversity of study scenarios within petroleum geology and the geosciences, the particular target application of the visual techniques is to easily provide field-based outcrop interpretations for subsequent construction of training images for multiple point statistics reservoir modelling, as envisaged within the VOM2MPS project. Despite the success and applicability of the visual approach, numerous drawbacks and probable future extensions are discussed in the thesis based on the conducted studies. Apart from elaborating on more obvious limitations originating from the use of mobile devices and their limited computing capabilities and sensor accuracies, a major contribution of this thesis is the careful analysis of conceptual drawbacks of established procedures in modelling, representing, constructing and disseminating the available surface geometry. A more mathematically-accurate geometric description of the underlying algebraic surfaces yields improvements and future applications unaddressed within the literature of geology and the computational geosciences to this date. Also, future extensions to the visual techniques proposed in this thesis allow for expanded analysis, 3D exploration and improved geological subsurface modelling in general.publishedVersio

Deutung von Wirkung in Organisationen des Sozialwesens : Ergebniszusammenfassung

Der vorliegende Bericht fasst die zentralen Resultate des Forschungsprojekts ‘Deutung von Wirkung in Organisationen des Sozialwesens’ zusammen. Das vom Schweizerischen Nationalfonds (SNF) zwischen 2019 und 2022 an der Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) geförderte Projekt verfolgte das Ziel, auf der Grundlage einer systematischen Literaturanalyse und Feldforschung in Organisationen des schweizerischen Sozialwesens Deutungsrahmen von Wirkung in vier ausgewählten Handlungsfeldern zu rekonstruieren und diese aufeinander zu beziehen. Die Ergebnisse zeigen erstmals auf breiter empirischer Basis auf, wie der Wirkungsbegriff in den Handlungsfeldern sowie im Sozialwesen allgemein gedeutet wird. Gemäss den Erkenntnissen orientiert sich die Deutung von Wirkung sowohl in der Literatur als auch in der Praxis an den Klient:innen sozialer Dienstleistungen. Während in der Literatur psychologische und soziale Wirkungszuschreibungen auf der individuellen Ebene handlungsfeldübergreifend dominieren, fokussieren Fach- und Führungspersonen in den Beschreibungen von Wirkung ihrer Arbeit auf psychologische Wirkungsziele. Ökonomische Wirkung wird in keinem Handlungsfeld vorrangig behandelt; von den Mitarbeitenden der untersuchten Organisationen noch weniger als in der Literatur. Darüber hinaus können die Klient:innen (und ihre Angehörigen) als primäre Adressat:innen der Wirkungsorientierung identifiziert werden: Sprechen Organisationen über Wirkung, richten sie sich eher selten an Politik, Verwaltung und Gesellschaft aus, sondern rücken die Nutzenden ihrer Angebote als Stakeholder in den Mittelpunkt

Cueva de Ardales, Province of Malaga

Artículo recopilatorio sobre los principales hallazgos y descubrimientos llevados a cabo en la Cueva de Ardales

Perceptual multivariate visualisation of volumetric Lagrangian fluid-flow processes

Lagrangian flow data in oceanography are highly complex, encompassing not only the underpinning Eulerian, advective, vectorial flow fields and the three-dimensional position coordinates of tracer particles but also supplementary trajectory information such as interaction radii of particles, lifecycle source-to-sink information and biochemical process data. Visualising all those data cooperatively in its three-dimensional context is a prime challenge, as it demands to present all relevant information to enable a contextual analysis of the flow process while preventing the most commonly-occurring perceptual issues of clutter, colourisation conflicts, artefacts and the lack of spatial references in fluid-flow applications. In this article, we present visualisation design approaches for 4D spatio-temporal data in their context and introduce a novel colour-mapping approach for 3D velocity tensors. The employed visualisation approach is evaluated towards perceptual adequacy and efficacy with respect to algebraic visualisation design and on an oceanographic case study. The technical and perceptual elements have further implications and applications for still-picture and animated volumetric visualisation design in related applications of the natural sciences, such as geological flow mapping

Global Modeled Sinking Characteristics of Biofouled Microplastic

Microplastic debris ending up at the sea surface has become a known major environmental issue. However, how microplastic particles move and when they sink in the ocean remains largely unknown. Here, we model microplastic subject to biofouling (algal growth on a substrate) to estimate sinking timescales and the time to reach the depth where particles stop sinking. We combine NEMO‐MEDUSA 2.0 output, that represents hydrodynamic and biological properties of seawater, with a particle‐tracking framework. Different sizes and densities of particles (for different types of plastic) are simulated, showing that the global distribution of sinking timescales is largely size‐dependent as opposed to density‐dependent. The smallest particles we simulate (0.1 μm) start sinking almost immediately around the globe and their trajectories take the longest time to reach their first sinking depth (relative to larger particles). In oligotrophic subtropical gyres with low algal concentrations, particles between 1 mm and 10 μm do not sink within the 90‐day simulation time. This suggests that in addition to the comparatively well‐known physical processes, biological processes might also contribute to the accumulation of floating plastic (of 1 mm–10 μm) in subtropical gyres. Particles of 1 μm in the gyres start sinking largely due to vertical advection, whereas in the equatorial Pacific they are more dependent on biofouling. The qualitative impacts of seasonality on sinking timescales are small, however, localised sooner sinking due to spring algal blooms is seen. This study maps processes that affect the sinking of virtual microplastic globally, which could ultimately impact the ocean plastic budget

Image-to-Geometry Registration on Mobile Devices – Concepts, Challenges and Applications

Registering natural photos to existing 3D surface models, particularly on low-power mobile devices, gathers increasing attention to a variety of application domains. The paper discusses up-to-date computation insights of the technique, condensing available literature and knowledge obtained from experiments across multiple research groups. Challenges like smartphone camera calibration or the sensor-based estimation of location and orientation are current research subjects, for which new data and experimental results are presented. Moreover, computing-related, practical challenges (e.g. device variability) are detailed to increase the technological understanding and reasoning on the limits of mobile devices. An overview of running projects utilising image-to-geometry registration methods shows the potential for mobile devices to, amongst others, improve flood hazard mitigation and hydrocarbon exploration with crowdsourced data

Efficiently simulating Lagrangian particles in large-scale ocean flows — Data structures and their impact on geophysical applications

Studying oceanography by using Lagrangian simulations has been adopted for a range of scenarios, such as the determining the fate of microplastics in the ocean, simulating the origin locations of microplankton used for palaeoceanographic reconstructions, and for studying the impact of fish aggregation devices on the migration behaviour of tuna. These simulations are complex and represent a considerable runtime effort to obtain trajectory results, which is the prime motivation for enhancing the performance of Lagrangian particle simulators. This paper assesses established performance enhancing techniques from Eulerian simulators in light of computational conditions and demands of Lagrangian simulators. A performance enhancement strategy specifically targeting physics-based Lagrangian particle simulations is outlined to address the performance gaps, and techniques for closing the performance gap are presented and implemented. Realistic experiments are derived from three specific oceanographic application scenarios, and the suggested performance-enhancing techniques are benchmarked in detail, so to allow for a good attribution of speed-up measurements to individual techniques. The impacts and insights of the performance enhancement strategy are further discussed for Lagrangian simulations in other geoscience applications. The experiments show that I/O-enhancing techniques, such as dynamic loading and buffering, lead to considerable speed-up on-par with an idealised parallelisation of the process over 20 nodes. Conversely, while the cache-efficient structure-of-arrays collection yields a visible speed-up, other alternative data structures fail in fulfilling the theoretically-expected performance increase. This insight demonstrates the importance of good data alignment in memory and caches for Lagrangian physics simulations

Modelling of tuna around fish aggregating devices: The importance of ocean flow and prey

Catch and distribution of tuna in the ocean are typically investigated with ocean basin-scale models. Due to their large scale, such models must greatly simplify tuna behaviour occurring at a scale below 100 km, despite interactions at this level potentially being important to both catch and distribution of tuna. For example, the associative behaviour of tuna with man-made floating objects, that are deployed by fishers to improve their catch rates (Fish Aggregating Devices; FADs), are usually ignored or simplified. Here we present a model that can be used to investigate the influence of tuna dynamics below the 100 km scale on larger scales. It is an Individual-Based Model (IBM) of a hypothetical, tuna-like species, that includes their interactions with each other, free-floating FADs and prey. In this IBM, both tuna and FADs are represented by Lagrangian particles that are advected by an ocean flow field, with tuna also exhibiting active swimming based on internal states such as stomach fullness. We apply the IBM in multiple configurations of idealized flow and prey fields, alongside differing interaction strengths between agents. When tuna swimming behaviour is influenced equally by prey and FADs, we find that the model simulations compare well with observations at the km scale. For instance, compared to observations, tuna particles have a similar stomach fullness when associated or non-associated to a FAD, tuna colonize at similar timescales at FADs after their deployment and tuna particles exhibit similar variations in continuous residence times. However, we find large differences in emergent dynamics such as residence and catch among different flow configurations, because the flow determines the time scale at which tuna encounter FADs. These findings are discussed in the context of directing future research, and an improved interpretation of tuna catch and other data for the sustainable management of these economically important species