Research On Marine Environment Data Dynamic Visualization Based On3D Virtual Earth

With the rapid development and gradually deepening promote of "Digital Earth","Digital Ocean", there are higher demands for the marine data multi-dimensional dynamic visualization system based on GIS. Marine environmental data with these characteristics include multiple-sources, heterogeneous, diverse formats, widespread distribution, massive volume, multi-dimensional and dynamic, which make the data processing method of marine data is quite different from the land-based GIS. How to effectively organize, and thus efficiently multi-dimensional dynamic visualization expression of these marine data, enable people to intuitively feel the connotation of ocean data, it’s one of the key technologies of Marine data visualization. This paper studies the hybrid terrain representation model for integration topographic and bathymetry, and process-oriented marine spatio-temporal process data model. This study also explores the visualization idea and specific method of the true multi-dimensional dynamic marine environmental data based on three-dimensional virtual earth. A prototype system is designed and implemented for marine data3D visualization based on SOA, and demonstrates the feasibility and benefit of the theory, methods and techniques in this study. The main works and innovations in this dissertation are summarized such as:(1) The paper explores the seabed DEM generation method based on the discrete point datasets, and achieves a complete flow to generate the bathymetry data through marine discrete sounding points and relative feature lines or points; For the differences between the land-sea terrains, such as spatial scale, resolution and so on, this study takes efficient, rapid and vivid display in three-dimensional virtual earth as the goal, proposes an improved hybrid land-sea terrain representation based on the quadtree, designs layered management mechanism for variety of the resolution elevation model, and achieves unified fusion rendering. In addition, the paper studies arbitrary shape high-resolution terrain data hybrid rendering algorithm, to improve the effect of three-dimensional expression of the local high-precision terrain data.(2) On the basis of comprehensive analysis the characteristics of the marine environmental data and the typical marine environmental spatio-temporal data model, for the marine spatio-temporal visualization requirements in3D virtual earth, the paper proposes a process-oriented marine spatio-temporal data model, it’s the basis for efficient expression the marine spatio-temporal data. Using the multi-dimensional data organization model NetCDF, studies the netCDF-based marine environmental data organization method and storage technology, to achieve unified description and management, which provides a valuable method for the efficient management and sharing of marine data.(3) Based on three-dimensional virtual earth, the paper researches multi-mode, multi-type visualization expression and analysis method of the marine scalar field data, and discusses the point, line, surface, volume process dynamic visualization of marine process data in detail, then focus on GPU-accelerated ray-casting volume rendering method. And achieves some typical scalar field data visualization methods, including cross-section, contour and isosurface rendering, at the same time, the paper also discusses continuous, smooth visualization in time dimension based on time interpolation. In addition, we propose improved3D arrows point icon of the vector field rendering method in the three-dimensional virtual earth, and achieve efficient dynamic visualization of the vector field. Through a variety of ways of visualization and analysis, which makes the temporal and spatial distribution characteristic and change trend of marine elements and phenomena visualization more clearing, intuitive, vividly, and provides a visual way to reveal the rules and characteristics of marine phenomena.(4) Relying on the existing3D GIS platform, it establishes a marine information three-dimensional visualization prototype system based on SOA, using the above researches, to realize3D integrated visualization and analysis of land-sea basic geographical information data and marine environmental data, and validates the theories, techniques and methods of the paper proposed by some typical data visualization.