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| Effects of interpolation parameters in Inverse Distance Weighted Method on DEM accuracy in dry鄄hot valleys of Yuanmou |
| Chen Juan, Luo Mingliang, Zhang Bin, Dong Chengyan, Chang Xiaoli |
| Land and Resource College, China West Normal University, 637009,Nanchong, Sichuan, China |
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Abstract Gully is often the result of serious degradation of ecosystem. In the dry鄄hot velleys the gullies are greatly developed, which destroy cultivated land and have caused serious land degradation and bring severe harms to land resources. Hence, it is meaningful to model terrain morphology DEM based on dry-hot valleys of Yuanmou, especially for the quantitative investigation of soil erosion at gully scale. In this study, high-accuracy and high-density elevation data at sampling points of a typical gully were obtained in Yuanmou by field surveying. Inverse Distance Weighted Method (IDW) interpolation was used to model the terrain surface. Mean error (E1 ) and root mean square error ( E2 ) were used to measure the difference when the weighted index, search points, search shapes and sector types changed. The check points and cross validation were adopted as well. The results showed that we can get the best interpolation effect when the weighted index was 2, neighborhood with 4 - 8 points, and interpolated with four directions. Through setting optimal parameters, the terrain surface can be simulated more actually. DEMs constructed by IDW have shown an ideal depiction of gullies in Yuanmou dry-hot valleys. The main morphological parameters are as follows: the whole area of the watershed is 0.011 km2, the average slope is 35.37°with the maximum 85.76°, and the density of regional gully is 3.95 km/ km2, with the cutting depth ranging between 7 m and 12 m.
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Received: 02 November 2013
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