System Design And Implementation Of Calculation And Analysis The Amount Of Channel Erosion And Deposition Based On Grid DEM

There are many rivers and lakes in China.As an important part integrate transportation network,to dredge the channel regularly and ensure the sufficient water depth is necessary.In order to improve the efficiency and economic benefit of dredging engineering,it demand accurate calculation of the amount of silt and siltation.The traditional calculation method is based on the physical data and mathematical model.The results of physical model are highly intuitive and accurate,but the investment is large in n large projects.The mathematical model takes a long time,the result is just a lot of data and cannot be visually displayedWith the rapid development of GIS technology,the use of digital elevation model(DEM)to calculate the channel sedimentation,not only improved the traditional method of heavy workload,low computation efficiency and low precision calculation results,but also has the advantages of visual result.At present,it has been the mainstream of the calculation method.There are many kinds of methods to calculate the earthwork volume based on DEM,such as the section method,the average height method,the triangulated irregular network method,the contour line method and the regular grid method ect.In this paper,taking the example of a certain channel in Dagang Port of Tianjin,the measured CAD data of April and December of 2015 were selected,and use Arc GIS to extract the depth data and the channel boundary and build the riverbed regular grid DEM.Based on the regular grid DEM,using re development technology based on Arc GIS Object,the author do achieve the goal of accurate and intuitive calculation of channel erosion and siltation,and obtain the spatial distribution thematic map of erosion and deposition.The features of this system are as follows:1)Setting the tolerance value of the grid difference calculation to filter the error caused by the measured data and the influence of the flow factor.The spatial distribution map of channel erosion and deposition is generated by grid transfer vector,vector fusion and vector grid overlap calculation;2)according the depth threshold set by the navigation standard,split the erosion and deposition changes into four grades: the "erosion zone","does not affect the navigation area","warning zone" and "affect the navigation area";3)set up the legend for each level of erosion and deposition,and make the thematic map of scour and silting,which can provide decision support for channel safety maintenance;4)custom three-dimensional coordinate axis to provide space reference for the three-dimensional displaying of the waterway DEM;...