Osg-based Visualization Of Flood Routing

China is a country which occurs more frequently floods.At the end of the last century, the Yangtze, Nenjiang, Songhua River floods have occurred to cause a significant loss of the national economy.To effectively prevent flooding , ensure the people's lives and property, in addition to strengthen embankments, flood diversion, storage areas, the use of 3D visualization technology to express all kinds of information, the mathematical model and the flow combination of analysis in the flood is an urgent problem to resolve.Flood routing simulation is important part and powerful analytical tool in the drainage basin of flood control and disaster mitigation fields.By using the 3D graphics library of OpenSceneGraph, We do a desktop system to develop a platform based on MFC framework to the flood routing simulation and achieve a 3D visualization of the drainage basin. The main contents as follows:(1) Terrain data process and water simulationCAD data will be converted to DEM data, and then using OSGDEM tool, the DEM data can be generated to the topography of the scene which have the corresponding texture and coordinates.we can simulate the movement of flood by using the graphics library of OSG(2) One-dimensional and two-dimensional flood models.Based on extend of the Saint-Venant equations,we use Preissmann format to discrete those equations, calculate flood routing process,and write the unsteady flow calculation program to calculate water level and flow.(3) Flood prediction model based on greysystemUse gray system model to predict the value of Z and Q of a cross-section in the future over a period of time .(4) Three-dimensional visualization of drainage basin.Three-dimensional visualization and flood routing model with a combinationof methods, provide a more intuitive and effective analysis means,that apply to water resources of the research and application.In this paper,we use calculated values to determine the river's surface location, at the same time to generate the corresponding water body, and add it to the terrain scene to achieve a three-dimensional visualization of drainage basin and remote control.