The algorithm improved to calculate the ln ( / tan # ) index is presented , in which the area of the current cell is included in the calculated total cumulative contributing area of downslide grid cell 提出一種簡單的地形指數(shù)in ( a / tanp )計算方法,該方法分別計算dem網格單元的a和tanp ,對坡度為。
The calculation method of ln ( / tan # ) index widely used is the multiple flow direction algorithm developed by quinn et al . it can been seen that , in the algorithm , the contour length normal to the direction of flow flowing out the current cell is used to determine both a and tan # , and that the calculated total cumulative contributing area of downslide grid cell does not include the area of the current cell 目前普遍使用的計算該地形指數(shù)的方法為多流向法。方法中計算和tan用的均是與流出單元網格流向垂直的等高線長。另外計算下坡單元網格累積匯流面積時沒有考慮欲計算ln ( tan )值的單元網格的面積,這些是不合理的。