【摘要】：溝壑密度是評價地表侵蝕影響,水土流失情況,進(jìn)行地貌類型分析等的重要指標(biāo)。文章基于研究區(qū)填洼后的DEM,利用地表匯流累積分析原理和柵格重分類方法,通過研究溝道覆蓋區(qū)柵格數(shù)與匯流累積柵格二值化閾值間的關(guān)系,選擇合適的閾值用于提取地表溝道。然后結(jié)合自然地表高程,分析合理的高程和相對高程柵格重分類閾值并進(jìn)行高程柵格二值化,將二值化結(jié)果作為乘積模板并配合柵格細(xì)化算法優(yōu)化溝道提取結(jié)果。最終利用1km~2單位面積規(guī)則格網(wǎng)對溝道提取結(jié)果進(jìn)行目標(biāo)柵格數(shù)統(tǒng)計計算,得到地表溝壑密度值。結(jié)果顯示,該方法基于30 m分辨率DEM提取的西安市地表溝壑密度均值為1.29km/km~2。除雁塔區(qū),其余各行政區(qū)統(tǒng)計均值與前人研究結(jié)果基本吻合。試驗(yàn)結(jié)果證明,基于本方法可以高效較精確地計算該市地表溝壑密度,分析結(jié)果可以量化研究區(qū)溝壑密度特征值以及通過柵格像元灰度變化體現(xiàn)溝壑密度變化趨勢。
[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.
【作者單位】： 西北農(nóng)林科技大學(xué)資源環(huán)境學(xué)院;
【基金】：國家自然科學(xué)基金資助項(xiàng)目“黃土坡耕地地表糙度對產(chǎn)匯流的影響研究”(41271288)
【分類號】：S157.1

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本文編號：2339956