Research And Implementation Of Visualization For Marine Scalar Field Data

More than70%of the earth surface is covered by the marine; the marine is of greatimportance to our human and society. Nowadays, together with the rapid developmentof science, scientists have found lots of valid methods to survey marine environment,and the amount of surveying data becomes larger and larger, so the demand ofvisualization for marine environment data becomes more and more urgent. While thetraditional2D visualization methods such as marine chart cannot meet the new needs,Digital-Earth-based methods used for3D visualization for Marine Environment Data(MED) are becoming increasingly popular. MED includes the vector field data and thescalar field data, the Marine Scalar Field Data (MSFD) such as Submarine BottomTerrain and Characteristics (SBTC), Seawater Temperature Salinity Density (STSD)plays a great role in the ship sailing and anchoring, submarine line paving, etc. Thevisualization for MSFD is of great importance to the visualization for MED.This dissertation has studied the methods for3D visualization for MSFD such asSBTC and STSD based on the Digital-Earth, including3D visualization for submarinebottom terrain using LOD model,3D modeling and visualization for submarinecharacteristics,3D visualization for STSD based on globe, etc. The contributions andrelevant work in this dissertation are as follows:1) The Submarine Bottom Terrain sampling points are scattered distributed. In orderto enhance the imitation, a Submarine Bottom Terrain modeling method isproposed, which constructs the Regular Square Grid modeling based on thesampling points. This method uses LOD model and has effective terrain renderingresult in3D visualization.2) In order to show more naturally and really SBTC, as the2D visualization of SBTCis lack of realism, while the3D methods cannot effectively reflect the distributionof each bottom characteristic, a method for SBTC of3D visualization is proposed.This method uses the submarine bottom terrain modeling based on LOD and thesubmarine characteristics texture modeling based on Tile Pyramid. And theproblem written above is effectively solved.3) In order to eliminate the evident boundary and the abrupt transition betweendifferent submarine characteristic textures, a smooth transition method based onTexture Transition Zone (TTZ) and Multi-Texture is proposed. This method usesPolygon Offset algorithm to generate TTZ, and smooth the transition based onMulti-Texture in every TTZ, which enhance the visualization quality of submarinecharacteristics.4) According to the distribution feature of the STSD sampling points, a method basedon profile is introduced into STSD visualization. This method realize the generation of Contour Maps and Coloring Map algorithm. The results seem well.5) Finally, using the above algorithms and methods, a3D visualization prototypesystem is designed and implemented. In which MSFD including SBTC and STSDis integrated. The system is integrated with the GKD-Earth platform. The results ofour system validate the effectiveness and correctness of the algorithms and methodsproposed in this dissertation.