with a regional network of 50 km x 50 km cell size, they explored the relationships among the 2 IACs and topographic features. Between the IACs there was a linear relationship that varied with DEM resolution. For a specific type of geomorphology, a threshold
resolution of DEM can be determined, below which the surface-area increment (i.e., IAC) is negligible. The results provided the first comprehensive estimate of the contributions of the topographic features, DEM resolution, and algorithms for the surface-area
increment, and indicated the scale-related properties and potential environmental consequences of topographic heterogeneity in various estimates of natural resources and ecosystem functions when area needs to be taken into account.