Optimization of topographic index computation

The topographic index is an important input parameter for TOPMODEL. It integrates saturation deficit basin and catchment area. The catchment area is demanded while we calculate topographic index. Conventional approaches to catchment computation include recursion, backtracking and traversing. However, these approaches are resource consuming and inefficient. In this paper, borrowing ideas from water downflow, we propose a novel method for computing the topographic index. The method is simple and efficient. Experimental results on real data sets show that the proposed method is more efficient than the traversing approach.