集水區坡長因子自動萃取之研究

An Automatic Delineation of Slope Length Factor for Watershed Soil Loss Estimation

林昭遠(Chao-Yuan Lin) ； 林文賜(Wen-Tzu Lin)

《中華水土保持學報》 30卷4期 (1999/12) Pp. 313-320

https://doi.org/10.29417/JCSWC.199912_30(4).0008

摘要

地理資訊系統配合通用土壤流失公式（USLE）或農業非點源污染模式（AGNPS）推估集水區土壤沖蝕量，已廣泛被使用。惟誤用參數將導致模式估算錯誤；尤其是坡長因子被誤算之情形最爲嚴重，模式推估過程中，多數學者對坡長因子之計算交待不清，或直接以網格之大小來估算坡長因子。本研究將USLE公式中之坡長因子提出討論，撰寫程式自動萃取坡長因子供集水區土壤流失量評估之用。

關鍵字

集水區 ； 坡長因子 ； 數值地形模型 ； 地理資訊系統

並列摘要

There is a trend to estimate watershed soil lass by using geographic information system coupled with Universal Soil Loss Equation (USLE) or Agricultural Non-Point Source Pollution Model (AGNPS). However, error estimation is readily to be seen in some research papers due to the misuse of parameters in the equations and/or in models. Because of ambiguity in slope length calculation or of directly using grid size as slope length, slope length factor is the parameter that could be mostly misused in soil loss estimation. This paper discusses the calculation of slope length factor in a watershed and develops a module that can extract the factor from each grid for the use of watershed soil loss estimation.

並列關鍵字

watershed ； slope length factor ； digital terrain model ； geographic information systems