Three-dimension Visualization Of Watershed Based On Multi-resolution LOD

Watershed Visualization is the key to the construction of the digital watershed,two-dimensional expression of the spatial information at some level can no longer meet theneeds of information management. How to use3D terrain visualization technology to expressall kinds of information within the basin, and to integrate with water analysis model foranalysis of the basin’s water body changes need to be resolved at this stage. The main studyarea is Three Gorges Reservoir Area watershed, the research of the watershedthree-dimensional terrain scenes construction and basin water model are dealt, the water bodyflow field simulation and the spread of point source pollution problems based on the flowfield are discuss emphatically, the Three Gorges Reservoir Area3D visualization system isconstructed. First, the Tile Pyramid of the terrain and image is built through the organizationof blocks, an effective watershed three-dimensional terrain scenes is constructed with theapplication of the quad tree data structure for dynamic scheduling and rendering of terrainblocks. On this basis, the boundaries of the river are extracted according to the cross-sectionpoint of the river; The mathematical model of the water body is the focus of the study ofwatershed visualization, there are shortcoming of difficult to integrate and to expand with theexisting commercial software, and some algorithms can’t meet the requirements of real-timeor accuracy, affect the simulation of accurate and scientific. In this paper, To solve theseproblems, principles of fluid mechanics are used to calculate the flow field within the riverand two drawing modes of the flow field are given, the details of the flow of the water areexpressed visually in the river, and the problem of water flowing numerical visualization issolved;Water pollution incidents have occurred some times in recent years, and posed a threatto the urban and rural water supply systems and water ecology along the coast of river. Inorder to make the environmental disaster caused by water pollution accident reduce to theminimum,it is necessary to predict and analyze the migration of polluting water bodiescaused by pollution accidents temporally and spatially. In this paper, cellular automata model is used to simulate the diffusion process of point source pollution, and the flow field as theimpact factor; This article also discussed the simulation of flood and flow of the water, andthis is applied to3D visualization system of the Three Gorges Reservoir watershed.Application of three-dimensional visualization of multi-resolution LOD in the Three GorgesReservoir watershed basin shows that: Multi-resolution LOD is the key to solve thethree-dimensional visualization of large scenes, real-time calculation of the flow fieldimprove the accuracy and scientificity of calculation in the water model and pollutiondispersion model, it is meaningful to the use of flood resource and pollution control.