Physiological Factors Measured Using Digital Elevation Model Data for Experimental Watersheds of the Taiwan Forestry Research Institute

以DEM資料量測林業試驗所試驗集水區地形因子

陸象豫(Shiang-Yue Lu) ； 謝漢欽(Han-Ching Hsieh) ； 陳貞樺(Chen-Hua Chen) ； 黃良鑫(Liang-Shin Hwang)

《台灣林業科學》 24卷3期 (2009/09) Pp. 197-203

https://doi.org/10.7075/TJFS.200909.0197

摘要

地形特徵為決定集水區水文特性的主要因子，對集水區水文模式的驗證及經營作業對集水區水量改變等均有決定性的影響。目前台灣試驗集水區的地形因子分析多沿用地形圖分析結果為藍本；然而由地形圖所取得的地形因子其精確度常因比例尺與人為誤差而遭詬病。隨著地理資訊及數位判圖技術的進步，集水區的地形特性已多改為由數化的地形資料快速萃取而得，除精確度大為提高外更可將誤差減到最低程度。緣此作者將林業試驗所福山、畢祿溪、蓮華池與扇平等目前仍進行觀測的試驗集水區，利用WinGrid系統分析各集水區數位地形資料，重新測定各試驗集水區的地形因子，並與先前餘地形圖獲得的數據相比較。分析結果獲知：集水區面積及與面積有關的地形因子，前後量測的結果差異甚大，足以影響集水區試驗結果。希望藉由精確的量測能對台灣地區試驗集水區研究有所助益。

關鍵字

地形因子 ； 試驗集水區 ； 數化地形資料

並列摘要

Physiographic factors are the most important characteristics in establishing the hydrologic conditions of a watershed. They are crucial for experimental watersheds for model calibration and determining the effects of forest management practices on water yields. Originally those factors of Taiwan's experimental watersheds were analyzed using topographic maps. The accuracy of values for factors obtained from maps and ground surveys has long been criticized due to the scale and man-made errors. With the development of geographical information system (GIS) and digital photogrammetric techniques, it is increasingly common to determine basin characteristics from digital elevation models (DEMs). In this context, the physical characteristics of Taiwan Forestry Research Institute experimental watersheds including those at Fushan, Piluchi, Lienhuachih, and Shanping were examined using WinGrid, computer software which combines techniques of GIS, remote sensing, related theories, and models of soil and water conservation for topographic analysis of watersheds. The results indicated that there were significant differences between physiographic factors measured using topographic maps and DEM data for area and area-related factors such as the circumference of watershed, form factor, compactness, and average slope. Hopefully the adjusted measurements will be helpful in improving watershed and hydrologic studies in Taiwan.

並列關鍵字

physiographic factors ； experimental watershed ； DEM data