Extracted The River Hydraulic Parameters Based On Airborne LiDAR And High Resolution Remote Sensing Data

The extraction of river hydraulic parameters and the hydraulic numerical simulation of open channel are the foundation of flood forecast and watershed hydrological simulation.Determination of the hydraulic parameters rapidly and accurately is the key problems to be settled urgently in the hydraulic simulation,but the field measured workload is big, low efficiency and the sampling density is finite.LiDAR data,which provides high precision digital surface model of the channel, effectively made up for the inadequacy of field work, providing a new means for the river hydraulic parameters calculation.This dissertation,has studied on xinhe.Airborne LiDAR,3D laser scanner and GF-1 satellite data are preprocessed to inverse the vegetation height and coverage,and then the river hydraulic parameters are calculated.Analyzing its impact on river hydrological simulation results in the platform of TUFLOW model.TUFLOW model is applied to study and analysis the impact of watershed hydrological simulation.The main content contains four parts:(1) Data preprocessing.Airborne LiDAR data and the high accurate point cloud data based on 3D laser scanning at the key area near the river are processed,through splicing,correction,removing coarse almost,adaptive TIN filting and interpolation,to divid into the ground and the non-ground point and obtain DEM、DSM、nDSM,which is applied to extract hydraulic parameters and hydrological simulation.(2) The inversion of vegetation height and coverage.In this paper,the tree height with total station is considered as a reference to analysis the error of tree height obtained by airborne LiDAR.The vegetation height model obtained by airborne LiDAR is established by the regression model and get 5.778% average relative error and the correlation coefficient R2 is 0.9854.The NDVI value of different features is calculated by GF-1 and then the vegetation coverage inversion is carried out by the binary model.(3) Extracting the river hydraulic parameters.Based on the classification of remote sensing data,the vegetation height and coverage information,roughness is calculated.The river sections are obtained by 3D laser scanner and airborne LiDAR respectively.The cross section information with 3D laser scanner is considered as a reference to analysis the error of centerline height,hydraulic radius and cross-sectional area obtained by airborne LiDAR.The source of erro is anlysised to reduce the error of extracting river hydraulic parameters by taking 3D laser scanner data as a supplement.(4) The simulation of the river hydraulic model.DEM after fusion based on airborne LiDAR and 3D laser scanner,roughness values and hydraulic radius are considered as based datas,2D TUFLOW hydraulic model is used to simutlate the water depth,flow velocity and roughness value for analsising the influence on hydraulic simulation based on different roughness values obtained by traditional experience and the method of paper proposing.