A Method for Accurately Calculating the Morphological Changes of Gully Heads and Gully Walls

Abstract

The invention discloses a method for accurately calculating morphology change of a gully head and a gully wall of a gully with a washing hole. The method comprises the following steps of: firstly, importing the determined gully terrain grid data into GIS (Geographic Information System) software and setting a coordinate projection system; secondly, cutting the terrain data of the gully into three parts according to a water collecting area, a gully wall and a gully bed boundary; importing terrain data of the gully wall into a file which can execute data operation and respectively rotating spatial coordinates around a Z axis and an X axis according to the certain angle; secondarily importing the rotated gully wall data into the GIS software and extracting a boundary point position of the gully wall in a GIS software environment to generate a face file; then generating TIN (Triangulated Irregular Network) by using the rotated space point position and the boundary file; converting the TIN into a DEM (Digital Elevation Model) with proper size of grids; and subtracting the DEMs at different stages to finally obtain the terrain change processes of different stages. The method disclosed by the invention can be used for generating the DEM accurately and quickly, is simple in operation and does not need complex three-dimensional space conversion operation.

Description

technical field [0001] The invention relates to a monitoring and calculation method for the shape evolution of gully walls, in particular to a method for accurately calculating the shape change of the gully head and wall of a gully with water flushing dimples. Background technique [0002] Gully erosion is a major form of soil erosion. According to the survey by the United States Department of Agriculture, the amount of gully erosion accounts for 18-73% of the total erosion (average is 35%); summarizing and analyzing the situation of gully erosion in various countries in the world, the amount of gully erosion accounts for 10-94% of the total erosion (average is 35%) 44%); in the hilly and gully areas of the Loess Plateau in my country, the area is 217,600 km 2 , the amount of gully erosion accounts for 60-90% of the total erosion; in the dry-hot valley area of ​​the Jinsha River, the annual average retrospective erosion rate of gullies in this area is about 50cm / year, the ma...

AI Technical Summary

Problems solved by technology

Since Shuishanwo is the negative topography of the lower part of the ditch wall, the topographic data measured by 3D scanners and other instruments will correspond to the Z value with a large difference in altitude due to similar or identical coordinates (X, Y) (the same coordinate (X , Y) has both the Z value corresponding to the inner concave hole and the Z value corresponding to the water collection area at the top of the inner concave hole), using it to directly generate a DEM has a large error, or even a wrong DEM. In addition, The topographical change of the ditch wall is not the change of altitude (Z), but the continuous retreat of the ditch wall at the head of the ditch, that is, the change of the X and Y axis directions, which is significantly different from the traditional soil erosion process

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