Abstract
The purpose of this paper is to test models by computing hill slope form in an area of 5ha. including about 80 measuring points data with the size of a grid of 25m×25m. Therefore computed profiles can be compared with actual profiles in slope-gradient distribution whose terrain indices F were known. The analytical solution of the slope-gradient distribution, with the values ranged from logS_1 to logS_2, could be approximately fitted to the linear equation. Each F_1 and F_2 of given point S_1 and S_2, in which F_1 and F_2 are area percentages of slopes less then each S_1% and S_2% than (S_1<S_2), are also obtained from the linear equation. Least-squares method is used to obtain a "best" value for terrain index F that maximizes the level of agreement between actual slope-gradient distribution and computed profile. The determined equation F was well expressed by logistic equation that was controlled by the value of slope standard deviation σ_m. This method produces a value of terrain index F that is sufficiently accurate in the present context. Agreement between theoretical profiles and measured ones for the 120 area data, is generally good, with the exception of profiles deformed by slumping. Therefore, the preliminary results suggest that the model can be used to simulate slope-gradient distribution according to the linear equation.
