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| Impacts of DEM Resolution and Surface Fitting Methods on Slope Estimation |
| Song Ruhua1,Bi Huaxing2,Osamu Nakakita3,Kazutoki Abe3 |
| 1.Chinese Academy of Forestry, 100091, Beijing, China;2.Beijing Forestry University, 100083, Beijing, China;3.Forestry and Forest Products Research Institute, Tsukuba, 305-8687 JAPAN |
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Abstract The paper studies the impacts of DEMs resolution and surface fitting methods on slope estimation in following aspects ,(1)3 different algorithms for surface fitting (minimum curvature method, inverse distance method and profiles method) have been used to derive DEM, the result showed that different surface fitting methods have little impact on slope estimation; (2) 7 DEM resolutions (the DEM grid size is 10 m, 20 m, 30 m, 40 m, 50 m, 100 m and 200 m respectively) were selected to compare the difference of slope estimation from DEM, the result shows that DEM resolution has a significant effect on the slope estimation. Average slope become smaller and standard deviation become larger when DEM resolution from fine to coarse; and (3) The different impacts of DEMs resolution on different slope ranges. Slope was further classified into 14 narrow groups, the cumulative frequency of slope shows that DEM resolution has different impact on slope estimation in different slope groups, these impacts mostly can be classified into 3 classes according to gradient, they are 0° - 10°, 10° - 35°, and more than 35°. In these classes, slope is underestimated (slope range from 0°to 10°), overestimated (slope range from 10° to 35°), or here is little impact on slope estimation (when slope is steeper than 35°) , respectively by DEM with coarse resolution.
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Received: 08 March 2003
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