EVITA - A Prototype System for Efficient Visualization and Interrogation of Terascale Datasets

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Large-scale computational simulations of physical phenomena produce data of unprecedented size (terabytes and petabytes). Unfortunately, development of appropriate data management and visualization techniques has not kept pace with the size and complexity of such datasets. For many simulations, the storage of the data itself, not to mention seeing and understanding it, is a serious problem. This project responds to this by developing a prototype, integrated system (EVITA) to facilitate exploration of terascale datasets. This system will be concerned with the storage and representation of very large datasets, their analysis and manipulation and rendering and presentation of the resulting images. This will allow unprecedented access to our CFD data sets, which we expect to lead to new fundamental understanding.The project focuses on time-varying datasets from computational fluid dynamic/hydrodynamic and oceanographic applications on structured, rectilinear or curvilinear grids; however, the EVITA system is applicable as a general visualization environment for other terascale datasets with similar underlying structure. Additionally, the system is amenable to distributed- or even remote-visualization uses. The cornerstone of the EVITA system is a representational scheme that allows ranked access to macroscopic features in the dataset. The data and grid are transformed using wavelet techniques while a feature-detection algorithm is used to identify and rank contextually significant features directly. This ranking is used to generate a four-dimensional significance map that incorporates application-specific knowledge, which in turn allows an encoding with efficient compression and a progressive representation of significant features in the data. From this, the EVITA system creates as a preview an efficient, "lossy" image of the desired data and lets the user select regions of interest (ROls) for further enrichment. These ' Rols are given higher priority in the encoded bitstream, and subsequently displayed faster. Preliminary results demonstrate the efficacy of this approach. The project takes a novel approach to terascale visualization by capitalizing on the expertise of a multidisciplinary team to integrate research from several disciplines into the EVITA system. This both brings many perspectives to bear on the problem, and ensures that our results are practically useful.