DEM解析度暨流向演算法对于集流面积计算之影响.pdf

地理學報 第三十九期：71-90 (2005) 71 JOURNAL OF GEOGRAPHICAL SCIENCE (39) : 71-90 (2005) DEM 解析度暨流向演算法 對於集流面積計算之影響 The Effect of DEM Resolution and Flow Direction Algorithms on Contributing Area Calculation * ** ** 楊奕岑 徐美玲 賴進貴 Yi-Chen Yang Mei-Ling Hsu Jinn-Guey Lay Abstract Digital Elevation Model (DEM) plays a very important role in hydrological simulation. Hydrological parameters such as contributing area can be calculated from DEM automatically. Contributing area is a common parameter for delineating channel cells and for evaluating the potential of soil erosion. But calculation of contributing area is usually affected by DEM resolution and flow direction algorithms. This paper presents a case study that evaluates these effects in a sub-watershed of the Chenyulan Hsi. Three flow algorithms were used to calculate the contributing area at different DEM resolutions. The result shows that within the same DEM resolution, the hybrid model retains the advantage of both single-flow and multi-flow models and yields the most reasonable output. However, some spatial errors occur when coarser resampled DEMs were used. The only parameter in the hybrid model, the flow direction threshold, strongly affects the simulated result. The higher the DEM resolution is, the * 國立臺灣大學生物環境系統工程學系研究助理 Research Assistant, Department of Bioenvironmental Systems Engineering, National Taiwan University. ** 國立臺灣大學地理環境