EnvirVis17
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Item EnVirVis 2017: Frontmatter(Eurographics Association, 2017) Rink, Karsten; Middel, Ariane; Zeckzer, Dirk; Bujack, Roxana;Item Extracting, Visualizing and Tracking Mesoscale Ocean Eddies in Two-dimensional Image Sequences Using Contours and Moments(The Eurographics Association, 2017) Banesh, Divya; Schoonover, Joseph A.; Ahrens, James P.; Hamann, Bernd; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackWe introduce a system to extract and track mesoscale eddies captured in massive global ocean simulations. The major strength and contribution of our system is its design, which is based on two-dimensional image data processing. The Cinema database [CD] enables the generation and storage of two-dimensional image data taken in-situ, i.e., the creation of images via a virtual camera generating images during the ongoing simulation. The problem of eddy extraction and tracking is simplified by our approach to the problem of finding, matching and tracking eddies in two-dimensional images, thus eliminating the task of processing the original three-dimensional data set. Our system can be used on a simple desktop computer and provides an intuitive interface allowing a scientist to perform an eddy analysis for global ocean data in real-time. We demonstrate the effectiveness of our implementation for a specific simulated data set.Item An InteractiveWeb-based Doppler Wind Lidar Visualisation System(The Eurographics Association, 2017) Jerome, Nicholas Tan; Chilingaryan, Suren; Kopmann, Andreas; Wieser, Andreas; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackWith Doppler wind lidar producing significant amounts of data, providing means to extract relevant information from the data that describes atmospheric phenomena such as rain and low-level clouds is of vital importance. However, a Doppler wind lidar with a 10 Hz sampling rate produces large-scale of data at approximately ten million data items per day; therefore, introducing challenges in perceptual and interactive scalability. We present an interactive web-based visualisation system that provides summary displays of the heterogeneous lidar data. Our system applies the client-server paradigm, where our server extracts information and encodes primary lidar attributes into image's colour channels. Then, we load these encoded images and show lidar data in multiple forms at the client-side. In contrast to script-based tools such as Matlab and Ferret, our system allows researchers to begin analysing the extensive data using a more top-down methodological approach. In particular, we implemented features like zooming, multivariate filtering, and hourly variance heat map, in which GPU shaders filter data according to specific attributes. With the encoded images readily stored at the server, researchers can browse through the vast amounts of data interactively.Item Intuitive Colormaps for Environmental Visualization(The Eurographics Association, 2017) Samsel, Francesca; Turton, Terece L.; Wolfram, Philip; Bujack, Roxana; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackVisualizations benefit from the use of intuitive colors, enabling an observer to make use of more automatic, subconscious channels. In this paper, we apply the concept of intuitive color association to the generation of thematic colormaps for the environmental sciences. In particular, we provide custom sets of colorscales for water, atmosphere, land, and vegetation. These have been integrated into the online tool: ColorMoves: The Environment to enable the environmental scientist to tailor them precisely to the data and tasks in a simple drag-and-drop workflow.Item Multivariate Visualization of Oceanography Data Using Decals(The Eurographics Association, 2017) Rocha, Allan; Silva, Julio Daniel; Alim, Usman; Sousa, Mario Costa; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackIn this paper, we present our results on the 2016 Compute Canada Visualization Contest, which centers around the visualization of multiple oceanographic data attributes. Our goal is to help researchers better understand the correlation between these attributes by providing an integrated data visualization. To accomplish this goal, we combine decals and colormaps in a layered fashion over temperature isosurfaces extracted from an oceanography model. We describe how decals can be deformed and animated over isosurfaces to convey the sense of flow given by the ocean currents. Our visualization design focuses on addressing requirements from experts, tailored for such datasets. The results highlight the potential of our approach towards accessing the tridimensional multivariate nature of such complex data.Item Setting up Virtual Geographic Environments in Unity(The Eurographics Association, 2017) Rink, Karsten; Bilke, Lars; Kolditz, Olaf; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackWe propose a setup for presenting complex heterogenous environmental data in a Virtual Reality environment. After a number of pre-processing steps required to integrate various data sets in a unified context, our workflow uses the Unity engine in combination with MiddleVR to create interactive applications for Virtual Reality environments to support research and evaluation for case studies containing domain-specific data from environmental monitoring and modelling. Typical challenges are described when handling such data in a graphics environment and solutions are proposed where possible. We give an overview of project structure and functionality added to Unity for visualisation of and interaction with the data and present an example application.Item STOAViz: Visualizing Saturated Thickness of Ogallala Aquifer(The Eurographics Association, 2017) Dang, Tommy; Nguyen, Long Hoang; Karim, Abdullah; Uddameri, Venki; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackIn this paper, we introduce STOAViz, a visual analytics tool for analyzing the saturated thickness of the Ogallala aquifer. The saturated thicknesses are monitored by sensors integrated on wells distributed on a vast geographic area. Our analytics application also captures the trends and patterns (such as average/standard deviation over time, sudden increase/decrease of saturated thicknesses) of water on an individual well and a group of wells based on their geographic locations. To highlight the usefulness and effectiveness of STOAViz, we demonstrate it on the Southern High Plains Aquifer of Texas. The work was developed using feedback from experts at the water resource center at a university. Moreover, our technique can be applied on any geographic areas where wells and their measurements are available.Item Video Compression for Ocean Simulation Image Databases(The Eurographics Association, 2017) Berres, Anne S.; Turton, Terece L.; Petersen, Mark; Rogers, David H.; Ahrens, James P.; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackClimate research requires monitoring a large range of spatial and temporal scales to understand the climate system and potential future impacts. Climate simulations are now run with very high resolution (1-10 km gridcells) ocean, sea ice, and atmosphere components, and can easily produce petabytes of output. This overloads storage systems and hinders visualization and analysis. Image databases can decrease storage sizes from petabytes of simulation output down to several hundred gigabytes of images. In this paper, we introduce video compression as a method to further decrease database sizes by 2-4 orders of magnitude. We compare compression and access speeds, compressed sizes, and compression quality over a range of settings. Quality is assessed through image quality metrics and expert feedback. Overall, we were able to show that video compression techniques provide an efficient means of storing image databases at a shareable size, while preserving image quality. This enables the wise use of available disk space, so scientists can more easily study the physical features of interest.Item Visual Characterisation of Temporal Occupancy for Movement Ecology(The Eurographics Association, 2017) Slingsby, Aidan; Loon, Emiel van; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackMovement ecologists study aspects of animals' movement, behaviour, and the factors that might drive these. Temporal patterns of local occupancy often reveal the type of usage at a location. We present and apply temporal tile-maps that embed temporal visual encodings into cartographic representations, and do so in an interactive visual analysis context. This reveals spatial variation in temporal occupancy that allows places to be identified and distinguished according to their use by animals. We apply these to GPS data from tracking gulls and illustrate the application to movement ecology. The tool that implements this and data are available to download and use.Item Visual Eddy Analysis of the Agulhas Current(The Eurographics Association, 2017) Raith, Felix; Röber, Niklas; Haak, Helmuth; Scheuermann, Gerik; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackLarge mesoscale eddies in the ocean can transport a substantial amount of heat and salt over large distances. Using highresolution ICON ocean simulation data, it is possible to detect and track eddies in the ocean and analyze their pathway. In this paper, we focus on the area of the Agulhas Current at the southern tip of Africa and present our results for eddy detection and eddy tracking. The Agulhas Current transports warm and salty water from the Indian Ocean towards the South Atlantic Ocean before it makes a strong turn back into the Indian Ocean. Some eddies associated with this current do not follow this turn back into the Indian Ocean, but travel north-west deeper up the Atlantic. We show how such eddies can be detected and tracked in the ICON model and how far some of them travel over the duration of one year. We also indicate which types of eddies follow these paths and give a visual analysis of eddy properties like volume and temperature.Item Visual Study of the Benguela Upwelling System using Pathline Predicates(The Eurographics Association, 2017) Nardini, Pascal; Böttinger, Michael; Scheuermann, Gerik; Schmidt, Martin; Karsten Rink and Ariane Middel and Dirk Zeckzer and Roxana BujackDue to the nutrient-rich water transported to the upper layer of the ocean, coastal upwelling systems are regions especially important for marine life and fishery. In this work, we focus on a visual analysis of the spatio-temporal structure of the Benguela upwelling system using pathline predicates. Based on the 3D flow field from an ocean model simulation, we first derive space- filling trajectories covering the full model grid. From these, we select and visualize pathlines related to upwelling. In a second step, we derive a 3D scalar field representing the pathline density, which is visualized using volume rendering techniques. Further analyses of the pathlines show a distinct annual cycle in the upwelling activity, which fits well to observation-based analyses found in literature.