Research On Application Of Urban Rainstorm Waterlogging Disaster Risk Assessment Based On UAV Oblique Photogrammetry Technology

Urbanization is a universal phenomenon in China and the whole world,along with the rapid urbanization process,the number of urban population is also increasing rapidly,as the most important habitat of mankind,the city and its environmental problems got more and more extensive attention.In recent years,major urban areas of the world have been subjected to very severe rainstorm and flood disasters,urban rainstorm and flood disaster has become the main factor to affect the safety of people's life and property in the 21st century.In order to improve the accuracy of monitoring and forecasting of urban flood disaster,it is of great significance to study the urban flood control and waterlogging.And because the urban waterlogging is extremely sensitive to the elevation influence,the high precision urban model can help to analyze the submergence accurately.Based on the comprehensive analysis of the present situation of urban rainstorm and flood risk assessment and urban three-dimensional model,in view of the high sensitivity of the present urban flood model to the terrain data and the accuracy of the study on the risk assessment of storm flood is limited by the accuracy of the basic terrain data,this paper creatively proposes the use of UAV oblique photogrammetry technology to improve the accuracy of the basic terrain data,combined with three-dimensional real-world modeling software Smart3D and the spatial analysis function of GIS,chooses the submerged depth as the key index to assess the storm flood risk.The main research contents of this paper include:(1)The characteristics and key technologies of the UAV oblique photogrammetry are analyzed in detail,including the combination of multi-view image,multi-vision image dense matching,digital surface model generation and real image correction,as well as the related technology of Smart3D.(2)This paper introduces the risk analysis,storm flood simulation and risk assessment method of urban storm flood in detail.(3)This paper choose the method of risk assessment based on scenario analysis the UAV oblique photogrammetry technique and GIS tools are used to simulate the submerged area and submerged depth scene of 1-hour rainfall in 6 different recurrence periods in the study area,and the simulation results were displayed by three-dimensional visualization.According to the submerged depth,this paper divide the risk into 6 grades,and analyses the risk degree of the study area under different recurrence period.The results show that:The results show that:? the urban three-dimensional model is of clear texture and high resolution using the UAV oblique photogrammetry technology,makes up for the lack of precision of the traditional modeling method;?By extracting submerged depth information of the study area under different recurrence period,and carrying out three-dimensional visualization submerged display,we can see the submerged situation of the research area intuitively,which can be used as the risk management basis of rainstorm waterlogging,and also have some reference value to the urban planning layout.