坡度变换的影响因素研究

发布时间：2018-10-17 09:22

【摘要】：坡度是对地面倾斜程度的定量描述,同时作为基本的地貌形态指标,是地学研究的重要内容之一。作为区域土壤侵蚀评价的重要参数,坡度通常基于中低分辨率的DEM进行提取。随着分辨率的降低,坡度会不断趋于平缓,这种现象被称为坡度衰减。通过坡度的变换,可有效的克服坡度衰减,使低分辨率坡度更好表达地表坡度变化,更有效支撑区域土壤侵蚀评价。本文的研究结果如下： (1)DEM建立方法对坡度及其变换有明显影响：本文利用数字地形图构TIN的方法和Hutchinson算法分别建立两种类型的DEM,以黄土区县南沟流域和黑土区拜泉县罗家屯沟小流域为研究样区,探讨了不同DEM类型对坡度变换的影响。结果表明：TIN-DEM表面存在的平三角,在坡度频率曲线上0-1度的坡度比例较大,不利对坡度的表达,而这种现象在Hc-DEM表面没有,所以利用Hc-DEM进行坡度变换精度更高。 (2)地形复杂程度对坡度变换的影响：以陡地形县南沟和平缓地形拜泉县为研究区,分别从不同地形复杂程度探讨对坡度变换的影响,结果表明：陡地形进行坡度变换后的更加接近于参考坡度,在陡地形地区进行坡度变换的效果要好于在平缓地区的坡度变换。 (3)分辨率差异对坡度变换的影响：以黄土区县南沟流域和黑土区拜泉县罗家屯沟小流域利用不同分辨率的DEM为基础提取坡度,对其分别从相邻分辨率和跨分辨率进行变换。结果表明,通过坡度变换,坡度衰减的现象得到了一定程度的纠正,通过对比两者的直方图相似度指数,相邻分辨率的进行坡度变换的精度要于高于跨分辨率坡度变换。
[Abstract]:Slope is a quantitative description of the slope degree of the ground, and as a basic geomorphologic index, it is one of the important contents of geoscience research. As an important parameter of regional soil erosion evaluation, slope is usually extracted based on low resolution DEM. As the resolution decreases, the slope tends to flatten, which is called slope attenuation. Through slope transformation, slope attenuation can be effectively overcome, low resolution slope can better express the change of surface slope, and more effectively support the evaluation of regional soil erosion. The results of this paper are as follows: (1) DEM method has a significant impact on slope and its transformation: this paper uses digital topographic map to construct TIN and Hutchinson algorithm to establish two types of DEM, to Nangou watershed in loess region. And the Luojiatungou small watershed of Baiquan County in the Black soil area as the study sample area, The influence of different DEM types on slope transformation is discussed. The results show that there is a flat triangle on the surface of TIN-DEM, and the slope ratio of 0-1 degree on the slope frequency curve is large, which is disadvantageous to the expression of slope, but this phenomenon does not exist on the surface of Hc-DEM. Therefore, the accuracy of slope transformation using Hc-DEM is higher. (2) the influence of terrain complexity on slope transformation: Nangou, a steep terrain county, and Baiquan county, a gentle terrain, are the study areas. The effects of different terrain complexity on slope transformation are discussed respectively. The results show that the slope transformation of steep terrain is closer to the reference slope. The effect of slope transformation in steep terrain area is better than that in flat area. (3) the effect of resolution difference on slope transformation: take Nangou watershed of loess area and Baiquan county of black soil area as small stream of Luojiatungou The domain uses DEM with different resolution to extract the slope, It is transformed from adjacent resolution and cross-resolution respectively. The results show that the slope attenuation is corrected to a certain extent by slope transformation. By comparing the histogram similarity index, the accuracy of slope transformation of adjacent resolution is higher than that of cross-resolution gradient transformation.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P208

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