基于汇流累积计算的沟壑密度分析方法
发布时间：2018-11-18 11:46
【摘要】：沟壑密度是评价地表侵蚀影响,水土流失情况,进行地貌类型分析等的重要指标。文章基于研究区填洼后的DEM,利用地表汇流累积分析原理和栅格重分类方法,通过研究沟道覆盖区栅格数与汇流累积栅格二值化阈值间的关系,选择合适的阈值用于提取地表沟道。然后结合自然地表高程,分析合理的高程和相对高程栅格重分类阈值并进行高程栅格二值化,将二值化结果作为乘积模板并配合栅格细化算法优化沟道提取结果。最终利用1km~2单位面积规则格网对沟道提取结果进行目标栅格数统计计算,得到地表沟壑密度值。结果显示,该方法基于30 m分辨率DEM提取的西安市地表沟壑密度均值为1.29km/km~2。除雁塔区,其余各行政区统计均值与前人研究结果基本吻合。试验结果证明,基于本方法可以高效较精确地计算该市地表沟壑密度,分析结果可以量化研究区沟壑密度特征值以及通过栅格像元灰度变化体现沟壑密度变化趋势。
[Abstract]:Gully density is an important index to evaluate the impact of surface erosion, soil erosion and geomorphological type analysis. Based on the theory of surface confluence accumulation analysis and grid re-classification method, this paper studies the relationship between the raster number in channel coverage area and the threshold value of confluence cumulative raster binarization, based on the theory of surface confluence accumulation analysis and grid re-classification method based on the DEM, after filling in the study area. Select the appropriate threshold to extract the surface channel. Then, combining with the natural surface elevation, the reasonable elevation and relative elevation raster threshold are analyzed and the elevation raster binarization is carried out. The binary result is used as the product template and the raster refinement algorithm is used to optimize the channel extraction results. Finally, the raster number of the target is calculated by using the regular grid of 1km~2 unit area, and the surface gully density is obtained. The results show that the average ravine density of Xi'an based on 30m resolution DEM is 1.29 km / kg ~ (-2). With the exception of the Yanta region, the statistical mean values of the other administrative regions are basically consistent with the results of previous studies. The experimental results show that the ravine density of the city can be calculated efficiently and accurately based on this method. The analysis results can quantify the characteristic values of the gully density in the study area and reflect the trend of the ravine density change through the grayscale change of the raster image element.
【作者单位】： 西北农林科技大学资源环境学院;
【基金】：国家自然科学基金资助项目“黄土坡耕地地表糙度对产汇流的影响研究”(41271288)
【分类号】：S157.1
本文编号：2339956
[Abstract]:Gully density is an important index to evaluate the impact of surface erosion, soil erosion and geomorphological type analysis. Based on the theory of surface confluence accumulation analysis and grid re-classification method, this paper studies the relationship between the raster number in channel coverage area and the threshold value of confluence cumulative raster binarization, based on the theory of surface confluence accumulation analysis and grid re-classification method based on the DEM, after filling in the study area. Select the appropriate threshold to extract the surface channel. Then, combining with the natural surface elevation, the reasonable elevation and relative elevation raster threshold are analyzed and the elevation raster binarization is carried out. The binary result is used as the product template and the raster refinement algorithm is used to optimize the channel extraction results. Finally, the raster number of the target is calculated by using the regular grid of 1km~2 unit area, and the surface gully density is obtained. The results show that the average ravine density of Xi'an based on 30m resolution DEM is 1.29 km / kg ~ (-2). With the exception of the Yanta region, the statistical mean values of the other administrative regions are basically consistent with the results of previous studies. The experimental results show that the ravine density of the city can be calculated efficiently and accurately based on this method. The analysis results can quantify the characteristic values of the gully density in the study area and reflect the trend of the ravine density change through the grayscale change of the raster image element.
【作者单位】： 西北农林科技大学资源环境学院;
【基金】：国家自然科学基金资助项目“黄土坡耕地地表糙度对产汇流的影响研究”(41271288)
【分类号】：S157.1
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