EnvirVis15

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https://diglib.eg.org/handle/10.2312/12460

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Multi-Purpose Exploration of Uncertain Data for the Video Monitoring of Ecosystems
(The Eurographics Association, 2015) Beauxis-Aussalet, Emma; Hardman, Lynda; A. Middel and K. Rink and G. H. Weber
Computer Vision is a promising technique for in-situ monitoring of ecosystems. It is non-intrusive and costeffective compared to sending human observers. Automatic animal detection and species recognition support the study of population dynamics and species composition, i.e., the evolution of species populations' size. Fixed cameras support continuous data collection, which can serve a variety of ecology research. Prior to in-depth data analysis, ecologists need to familiarise with the dataset, and with the limitations of video technologies. We propose an interactive visualization system for exploring the video data. It addresses user needs for i) eliciting information of interest for specific studies; and ii) identifying the uncertainty factors inherent to video technologies. We discuss generalisable interaction principes and illustrate them with screenshots of an online prototype.
Real-Time Visualization of Urban Flood Simulation Data for Non-Professionals
(The Eurographics Association, 2015) Grottel, Sebastian; Staib, Joachim; Heyer, Torsten; Vetter, Benjamin; Gumhold, Stefan; A. Middel and K. Rink and G. H. Weber
Perception and understanding of risk in predictive flood simulation data is a key factor in flood risk management. However, scientific visualizations are often hard to grasp for non-professionals. We present a visualization tool for interactive, realistic flood water rendering, incorporating a variety of optical effects. Our implementation is based on state-of-the-art algorithms of interactive computer graphics using animated texture coordinates. The flood simulation data contains water depth level and a flow field. Together with terrain elevation and buildings our tool allows for natural understanding of the data. We maintain interactive frame rates on standard desktop computers. Our results were judged useful by average citizens and political decision makers.
Spatial Aggregation of Mobile Transect Measurements for the Identification of Climatic Microenvironments
(The Eurographics Association, 2015) Häb, Kathrin; Middel, Ariane; Ruddell, Benjamin L.; Hagen, Hans; A. Middel and K. Rink and G. H. Weber
Mobile transect measurements retrieve high-resolution observations revealing the spatial variation of atmospheric properties throughout an urban landscape. A sensor platform is moved through a study site with varying urban form, collecting a data set that can be used to investigate the multifaceted impacts of different building and landscape configurations on atmospheric properties. To generalize such findings, it is imperative to include transect runs representing different points in time and potentially different meteorological background conditions. However, the analysis of a set of mobile transect measurement runs is challenging because of the strict spatio-temporal dependence and multivariate nature of each recorded sample. In this study, we provide visual support for the identification of coherent climatic microenvironments within a study site using mobile transect measurements taken at different points in time and over diverse routes. A regular grid is used to spatially aggregate the data, and resulting summaries are classified according to similar multivariate relationships using clustering techniques. Finally, each grid cell is visualized using a radial glyph encoding cluster membership, predominant wind direction for each transect run, and the number of transect runs traversing this grid cell. The approach has been tested using a data set recorded in Gilbert, Arizona, USA, and it shows potential to identify spatially contiguous regions of similar microclimate.
An Interactive Web-Based Geovisual Analytics Tool to Explore Water Scarcity in Niger River Basin
(The Eurographics Association, 2015) Lei, Ting L.; Liang, Xing; Mascaro, Giuseppe; Luo, Wei; White, Dave; Westerhoff, Paul; Maciejewski, Ross; A. Middel and K. Rink and G. H. Weber
Assessing the needs for adaptation and mitigation strategies to climate change and variability in Niger River Basin is a key for future development in Western Africa. There are two major challenges in terms of the assessment: the first is that future projections in water availability based on the historical trends are hard to assess under uncertainty, and the second is that human activities and population growth play a decisive but very uncertain role in environmental impacts. In order to address both challenges, we have developed a geovisual analytics tool for exploring simulation results under combinations of climate models, climate policies, and future population growth. Moreover, our tool is capable of ensemble-visualization and allows users to explore agreement levels among different climate models to assess future uncertainty.
Web-Based Visualization of the Global Change Assessment Model
(The Eurographics Association, 2015) Luo, Wei; Chang, Zheng; Kong, Lilian; Link, Robert; Hejazi, Mohamad; Clarke, Leon; Maciejewski, Ross; A. Middel and K. Rink and G. H. Weber
The Global Change Assessment Model (GCAM) is an integrated assessment tool for exploring consequences and responses to global change. However, the current iteration of GCAM relies on NetCDF file outputs which need to be output from the model and then exported for visualization and analysis purposes. Such a requirement limits the uptake of this modeling platform for analysts that may wish to explore future scenarios. In this work, we present a web-based geovisual analytics interface for GCAM. Challenges of this work include enabling both domain expert and model experts to be able to functionally explore the model. We explore the use of various aggregation layers, coordinated views and how choices of icons can enhance the understanding of the underlying data. Our primary focus is on understanding the simulated impact of climate change on sectors of the global economy. To demonstrate our work, we present a case study which explores the potential impact that the China south-north water transportation project in the Yangtze River basin will have on projected water demands.
Visualizing Category-Specific Changes in Oblique Photographs of Mountain Landscapes
(The Eurographics Association, 2015) Jean, Frédéric; Albu, Alexandra Branzan; Capson, David; Higgs, Eric; Fisher, Jason T.; Starzomski, Brian M.; A. Middel and K. Rink and G. H. Weber
Our paper proposes a method for visualizing the spatial distribution of classes for a multi-class image segmentation problem. We apply this method for the case of mountain landscape images, where classes are defined by landscape categories. The proposed method builds class-specific distribution maps. Our contribution is two-fold. First, the class-specific distribution maps allow for the visualization of class-specific changes computed from pairs of images depicting the same landscape at different moments in time. Second, these maps enable us to calculate prior class probabilities for statistical scene segmentation purposes.
A Collaborative Web-Based Environmental Data Visualization and Analysis Framework
(The Eurographics Association, 2015) Lukasczyk, Jonas; Liang, Xing; Luo, Wei; Ragan, Eric D.; Middel, Ariane; Bliss, Nadya; White, Dave; Hagen, Hans; Maciejewski, Ross; A. Middel and K. Rink and G. H. Weber
We present an environmental data visualization framework that features synchronous and asynchronous multi-user interaction with all the benefits of modern web-based applications, such as easy accessibility and cross-platform compatibility. In contrast to outdated web-based network protocols, the proposed framework uses HTML5 Web- Sockets to enable full-duplex communication between server and clients. To demonstrate the framework, we chose the ecological problem of water scarcity in Africa. In this case study, water scarcity is calculated and visualized using various models and parameters, which can easily be shared among users and devices. Hence, we show the potential and the utilization of web technologies for collaborative environmental data exploration on distributed desktop and mobile devices.
VafusQ: A Visual Analytics Application with Data Quality Features to Support the Urban Planning Process
(The Eurographics Association, 2015) Triana, John A.; Zeckzer, Dirk; Hernandez, Jose T.; Hagen, Hans; A. Middel and K. Rink and G. H. Weber
Fast changing urban systems pose huge challenges for planners and governments. One major challenge is to provide optimized facilities systems fulfilling all the basic citizen needs such as food, education, security, and health. To provide these, the deficit of the complete system needs to be analyzed and quantified. An additional, important problem is the quality of the underlying data influencing the analysis. Often, the data is, e.g., incomplete, not accurate, or not reliable. The goal of this paper is to support the analysis of the deficit for the facilities system of Bogotá by taking into account data quality issues. Our contributions are: the inclusion of data quality in the urban planning process, the design of a novel visualization technique to represent data quality, the implementation of an application to support the analysis of the facilities system, and a case study with experts assessing the usability and usefulness of the application. As a conclusion, the experts find the application useful for the analysis tasks and the inclusion of data quality features important and comprehensible.
Towards Interactive Definition of Fast Surrogate Models for Geochemical Simulations Using Visual Analysis
(The Eurographics Association, 2015) Jatnieks, Janis; Sips, Mike; Lucia, Marco De; Dransch, Doris; A. Middel and K. Rink and G. H. Weber
Geochemical models serve wide-ranging geoscientific applications for underground resource exploitation, aquifer remediation, gas storage and similar problems. Such models are time consuming to calculate. Replacing the fullcapability simulation model, for each element of spatial discretization, with a fast surrogate is a promising acceleration approach for this problem. The balancing of speed and accuracy trade-off inherent to the surrogate modeling approach requires expert involvement and is best supported interactively. In this paper we argue that Visual Analysis has a prominent role to play for facilitating this process. It allows to involve expert knowledge regarding the specific characteristics of application scenario as part of the surrogate creation process. We describe the core problem of accelerating geochemical simulation by surrogate models and outline a strategy for approaching it with Visual Analysis.
Mining Social Images to Analyze Routing Preferences in Tourist Areas
(The Eurographics Association, 2015) Torrisi, Alessandro; Signorello, Giovanni; Gallo, Giovanni; Salvo, Maria De; Farinella, Giovanni Maria; A. Middel and K. Rink and G. H. Weber
Social media platforms provide a useful source of data for environmental planning. In the last years these data have been exploited to perform social behaviour analysis. This work uses the huge amount of georeferenced images publicly available on social media as a source of information to infer the behaviour of tourists. Visual analytic mapping tools combined with the Parzen-Rosenblatt non-parametric kernel density estimation give us visual clues to assess the attractiveness of tourist geographical areas. To investigate the preferred combinations of locations visited by the tourists within a time window of few days we propose to mine association rules using the Apriori algorithm. A prototype of an integrated system to visually perform the suggested analysis has been realized and the paper reports about some of case studies performed with it.
Visualization of 2D Uncertainty in Decadal Climate Predictions
(The Eurographics Association, 2015) Böttinger, Michael; Pohlmann, Holger; Röber, Niklas; Meier-Fleischer, Karin; Spickermann, Dela; A. Middel and K. Rink and G. H. Weber
In recent years, climate prediction systems based on coupled climate models are used for investigating the climate predictability on a decadal time scale. Based on ensemble simulation techniques applied and hindcast experiments carried out first, the predictive skill of a system can be derived. The ensemble simulations used for the decadal climate predictions enable the issuing of probabilistic information along with the quantities predicted. In this work, we focus on the concurrent visualization of three related 2D fields: the forecast variable, here the 2m temperature anomaly, along with the corresponding predictive skill and the ensemble spread. We show exemplary solutions produced with three different visualization systems: NCL, Avizo Green and ParaView.
Frontmatter: EnvirVis 2015 Workshop on Visualisation in Environmental Sciences
(Eurographics Association, 2015) Rink, Karsten; Middel, Ariane; Weber, Gunther; -
Probability Maps for the Visualization of Assimilation Ensemble Flow Data
(The Eurographics Association, 2015) Höllt, Thomas; Hadwiger, Markus; Knio, Omar; Hoteit, Ibrahim; A. Middel and K. Rink and G. H. Weber
Ocean forecasts nowadays are created by running ensemble simulations in combination with data assimilation techniques. Most of these techniques resample the ensemble members after each assimilation cycle. This means that in a time series, after resampling, every member can follow up on any of the members before resampling. Tracking behavior over time, such as all possible paths of a particle in an ensemble vector field, becomes very difficult, as the number of combinations rises exponentially with the number of assimilation cycles. In general a single possible path is not of interest but only the probabilities that any point in space might be reached by a particle at some point in time. In this work we present an approach using probability-weighted piecewise particle trajectories to allow such a mapping interactively, instead of tracing quadrillions of individual particles. We achieve interactive rates by binning the domain and splitting up the tracing process into the individual assimilation cycles, so that particles that fall into the same bin after a cycle can be treated as a single particle with a larger probability as input for the next time step. As a result we loose the possibility to track individual particles, but can create probability maps for any desired seed at interactive rates.

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