Method of extracting slope unit in DEM

Abstract

In view of the slope mutation of the slope unit extracted in the prior art, the invention provides a method of extracting a slope unit in a DEM (Digital Elevation Model). The method comprises the following steps: first, determining a ridge and valley area; then, delineating the boundaries of homogeneous small closed areas in the ridge and valley area along a point at which the sudden change of terrain is the most concentrated; and finally, combining the homogeneous small closed areas having the same normal vector to form a slope unit. Specifically, the method comprises the following steps: first, determining the surface shape of a grid unit according to the mean curvature of the grid center point, and determining a ridge and valley area; then, extracting a high-pixel part in a ridge and valley shape skeleton closed network to obtain the boundary lines of homogeneous small closed areas; and finally, carrying out plane fitting and combining on the small areas to obtain a slope unit. Themethod is based on a reliable principle, and has a simple and scientific process. There is no need to complete DEM filling and later artificial correction in advance. The extracted slope unit is homogeneous, and can satisfy the assumption of landslide stability analysis homogeneity.

Description

technical field [0001] The invention relates to an image analysis method, in particular to a method for extracting slope units from DEM, and belongs to the field of general image data processing or generation, and the technical field of environmental geological disaster prevention and control. Background technique [0002] The selection of forecast unit is the primary premise of regional landslide forecast technology. Proper selection of forecast units can not only improve the accuracy of forecast but also help to guide the correct emergency response measures to geological disasters. In the existing three forecasting techniques of physical forecasting, statistical forecasting and causal forecasting, accurate selection of forecasting units is particularly important for physical forecasting models, because physical forecasting models need to use forecasting units as calculation units, and select relevant units according to their morphological characteristics. The matching mec...

AI Technical Summary

Problems solved by technology

However, the slope units extracted by this method cannot identify changes in slope other than the direction of water flow, resulting in the fact that the slope of the extracted slope units is not uniform

For example, the water flow direction extracted by the D8 algorithm can only reflect the characteristics of the steepest slope, but cannot reflect the direction of water flow, especially the slope change or even sudden change of the slope foot or platform.

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