Research And Implementation Of The Visualization Of DongTing Lake Water Area

Three-dimensional visualization of water areas can not only display the 3D geographical environment around the water areas and 3D dynamic flow of water in the water areas, it can also convert numerical value of hydrologic measure related to the calculation of hydraulics into information represented by graph or image, which is an important part of "Digital Valley". In the construction of flood control, DongTing Lake is an important part of the middle and downstream area of Yangtze River. It undertakes enormous tasks of flood diversion and storage of Yangtze River flood season. Research on the visualization of DongTing Lake water area can provide decision support of waters management, development or flood diversion and storage.Emphasis of visualization of water areas focus on how to simulate large scale 3D geographical environment efficiently and smoothly, simulate vivid 3D dynamic flow effect of water and show the information of water level and flow, which is also the difficulty to develop Visualization System of DongTing Lake water area. Current implementations of water area visualization focus on the integration of GIS system and hydrology-hydraulical model, which places emphasis on solving and numerical simulation of complex hydrodynamic model and has a certain lack of efficiency of the system and 3D visualization. To solve the two aspects of deficiency, we use the solution based on the rendering engine OSG and OSGEarth in 3D visualization and use the BP neural network forecasting method in water level computing.The main work of the paper includes:1. With regard to the water level visualization of the visualization of the water areas, we investigate the calculation method of the river water level. We propose the solution of using BP neural network method to predict river water level, which solves the complex and inefficient problems in the traditional water level calculation.2. We study the 3D visualization of geographical environment and dynamic visualization of water flow. For the management and scheduling of large scale topography and geomorphic data, we propose the solution based on the tile data services technology of OSG and OSGEarth 3D rendering engine and texture indexing mechanism based on the OSGEarth. And efficiently implement the dynamic loading and fluent scheduling of the 3D geographical environment. For the dynamic 3D visualization of the water flow, we propose the solution of first modeling the water body using FFT method based on the wave spectrum, and then rendering the water according light condition using OSG, which finally achieves a vivid dynamic flow effect of 3D water.3. By applying the introduced technology and solutions, we have implemented a visualization system of DongTing Lake water area, which achieves roaming large scale 3D geographical environment, dynamic 3D visualization of the water flow in multiple scenarios, and the visualization of water level at all of the gauging stations and any point of specific riverway.