Research On Flood Inundated Areas Quickly Mapping And 3D Visualization

Flood disaster is a serious natural disaster in the world. Significant casualties and economic losses are caused by flood disaster every year. And it seriously affects the balance and stable development of the world economy. The traditional "have means to resist" way of flood control, can’t meet the requirements of flood control in modern society. We need a new method of combination engineering and non-engineering measure for flood. The flood risk map as a non-engineering flood control measure, provides a comprehensive flood information for flood control and emergency rescue work, and provides scientific basis for escape and decision-making. At present, the study on flood risk map has obtained some achievement, and has established the basic system of flood risk defense. But the real-time study of flood risk map is less. For example, as the flood coming, how to quickly make the flooded areas according to the upstream reservoir inflow is still a problem. This paper was based on the existing principle of flood risk map making, took the wolong reservoir watershed as study area, put forward the combination of hydrology and hydraulics method, fast completed the flood risk map, carried on the 3d visualization, and strived more time for residents to evacuate.Firstly, this article studies the method of terrain data quickly getting. Under the condition of shortage of terrain data, this article used the software of geographic information system (GoodyGIS) to get topographic data of the study area. After dealing with the terrain, this article quickly completed the flood risk map by combined hydrology and hydraulics method. Firstly, calculate the river flood water line by using MIKE11. And extract the ground elevation data of study area by using geographic information system (GoodyGIS). With the function of the raster calculator, DEM elevation data subtracts river section water to get the study area flood scope. Then, quickly complete four frequency (0.1%,0.2%,1%,2%) flood risk map of wolong reservoir. Finally, evaluate the effect of the method by using the hydraulic method. The results show that the speed of the combined method of hydrology and hydraulics is fast and its precision can be good satisfied the purpose of flood control and disaster mitigation. This method has been used in large and medium-sized reservoirs flood risk map making in Dalian.Secondly, using the function of three-dimensional network spatial analysis and management in ArcGIS, the article studied the 3d visualization of flood risk map. Using the three-dimensional space analysis function in ArcScene, the article established the 3d visualization scene to simulate the dynamic process of flood. And using the three-dimensional animation function in ArcScene, the article realized the three-dimensional dynamic scan of wolong reservoir.Finally, the article studied the escape route and 3d visualization. Manually draw the regional road network in ArcGIS and built the road network datasets. According to the idea of "point-line-point", select the reasonable refugee camps and migration paths. And translate the 2d flood risk map into 3d visualization. Analyze the completed flood risk map, and consider the submerged area, water depth and diachronic factors to make the emergency transfer plans, which will provide a scientific basis for flood control and emergency rescue.