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Chengdu University of Technology (2019)

Study on High-precision Detection Method for Rill Morphology in Yuanmou Dry-hot Valley Region

邓青春;

Titre : Study on High-precision Detection Method for Rill Morphology in Yuanmou Dry-hot Valley Region

Auteur : 邓青春;

Grade : Doctoral Dissertation 2019

Université : Chengdu University of Technology

Résumé partiel
Rill Erosion is the main mode of slope surface erosion.The morphology of rill is a very important factor that determines slope runoff and the amount of soil loss.The relations between parameters of rill morphology can be used to describe the erosion process of rill.Therefore,getting high-precision morphology parameters of rill is significant for revealing the development and evolution of rill erosion.Although some scholars have used various technology to detect the rill area terrain,few scholars have studied the mode of terrain mapping and the relationship between DEM resolution and the rill morphological parameters.This paper takes rills developed from the Yuanmou dry-hot valley region as the research object to discuss the effective technological methods for the detection of high-precision morphology parameters of rill.Through building control network of the rill area,the terrain of rills can be measured using self-made needle plate,total station,3D laser scanning and close-range photogrammetry technique,and the morphological parameters of rill can be obtained by GIS.In order to establish the best detection technology and method,analyzed the precision of elevation of different measuring methods and its effects on morphology parameters of rills,the quantitative relationship between resolution of DEM and parametric error of rill morphology.The results will offer a technological support for study the control of soil erosion in Yuanmou dry-hot valley region.The main conclusions are as follows :(1)6mm is the best scanning step for the cross section of rill.Processing the point cloud data of different scanning steps,the results showed that with increasing of the scanning step would considerably reduce the data quantity,but the parametric error of rill morphology will be different.Contrast with the parametric of rill morphology based on close-range photogrammetry,the absolute error and relative error of the width,depth and aspect ratio of the rill are minimized when the scanning stepsize is 6mm,the line length of cross section decreases with the increase of scanning step size ;when the scanning step size is 4mm,a relatively high accuracy cross-section area can be obtained.Therefore,under the condition of reducing the data quantity and the parametric error and precision,the best scanning step for studying cross section of rill is 6mm.(2)Different data processing methods affect the precision of parameters of rill morphology.Polyline method,arc method and spline method are respectively used to fit the ditch edge measured by total stations and their relative errors in the length of ditch line are all small.Arc method has the smallest relative error in both the length of ditch line and rill erosion area.Filters have little effect on the width,depth and aspect ratio of rills but a remarkable impact on the area and line length of the cross section

Mots clés : Rill; Morphology Parameters; High-precision; DEM;

Présentation (CNKI)

Page publiée le 14 octobre 2020