基于直方图匹配的地面坡谱尺度下推模型研究--以陕北韭园沟样区为例  

Histogram matching based downscaling model of slope spectrum:A case study in Jiuyuan watershed of northern Shaanxi

作　　者：詹蕾[1] 汤国安[1] 张婷[1] 党维勤[2] 

机构地区：[1]南京师范大学虚拟地理环境教育部重点实验室,江苏南京210046 [2]黄委会绥德水土保持科学试验站,陕西绥德718000

出　　处：《干旱区地理》2008年第5期772-778,共7页Arid Land Geography

基　　金：国家自然科学基金(40671148，40571120)

摘　　要：建立坡谱的尺度下推模型,有利于揭示地面坡谱的尺度依赖性。以5 m、25 m两种分辨率DEM为实验数据,应用遥感数字图像处理中直方图匹配的原理,对两种分辨率DEM获得的坡谱进行尺度下推。实验采用按不同Douglas压缩阈值(不同简化程度)得到的5 m、25 m两种分辨率的DEM数据,获得不同压缩阈值的DEM坡谱下推模型系数与地形因子之间的关系,最终建立两种分辨率DEM数据的坡谱尺度下推模型。将这种方法在陕北黄土丘陵沟壑区韭园沟样区进行验正,同时将模拟结果与原始5 m分辨率DEM数据所得的坡谱进行比较,试验结果表明,该模型能够比较理想的将25 m分辨率DEM的坡谱直接转换为5 m分辨率DEM的坡谱,方法简单易行,精度良好。Slope is a parameter which reflects the rate of inclination that earth＇ s surface incline relatively to horizontal plane. It is also the one of most important quantitative index that describe the earth＇ s surface. Slope spectrum can reflect the macroscopical hypsography characteristic of surface. For the same type of physiognomy, different slope spectrum correspond to different DEM horizontal resolution. So it is necessary to study DEM＇ s slope spectrum scaling. Downscaling model of slope spectrum is the first step of landform information scaling . It is of great significance for revealing the scale dependence of slope spectrum. This study downscale the 25 m DEM＇ slope spectrum to 5 m＇ one by the histogram＇ s matching method in digital image processing, for the DEM grid data is similar to remote sensing image. 3D Douglas compress method is employed to obtain DEMs at two different resolution levels and eight different threshold value, which express the relief of different surface roughness. After deriving slope spectrum of DEMs of two kinds of resolution, the slope spectrum downscaling model between them could be founded by the histogram＇s matching method under each different threshold value, which indicates different simplified degree of landform. The relationship between the coefficients of downscaling model and terrain variables is found at each different threshold value as well, which lead to the construction of the final downscaling model of 25 m DEM＇ slope spectrum and 5 m DEM＇ s. This model is verified in a case study in Jiuyuangou of loess hill-gully area. Then, the slope spectrum derived from this method is compared with the one derived from original 5 m resolution DEM. The result shows that the model could achieve the transformation from 25 m resolution DEM＇ s slope spectrum to 5 m resolution DEM＇ s effectively and accurately in loess hill-gully area. The method lays a foundation for more study of slope spectrum downscaling in other types of physiognomy area, so that a more common d

关 键 词：尺度 地面坡谱 下推模型 

分 类 号：P208[天文地球—地图制图学与地理信息工程]