Moore Terrain Derivatives Tool

Secondary topographic attributes combine two or more primary attributes (slope, aspect, plan and profile curvature, flowpath length, and upslope contributing area), and can be used to characterize the spatial variability of specific hydrologic, geomorphic, and ecological processes occurring in landscapes (Wilson and Gallant, 2000). The Moore Terrain Derivatives tool generates two of these secondary topographic attributes from an input digital elevation model, and can be used to infer surface characteristics about the susceptibility of landscapes to erosion (Stream Power Index (SPI)) and the landscape distribution of soil water movement and accumulation (Topographic Wetness Index (TWI)). See Moore and others (1993).

By combining these primary attributes, our ability to understand the landscape characteristics that involve hydrology and geomorphology or ecology are greatly enhanced compared to what can be gained from looking at just a single attribute.

The Moore Terrain Derivatives tool derives an estimate of flow accumulation, called Specific Catchment Area, which is calculated using the D-infinity approach (Tarboton, 1997). The next page details how the D-infinity approach works.

 

Moore, I.D., Gessler, P.E., Nielsen, G.A. and Peterson, G.A. (1993). Soil attribute prediction using terrain analysis. Soil Science Society of America Journal, 57(2): 443–452.

Tarboton, D. G. (1997). A new method for the determination of flow directions and upslope areas in grid digital elevation models. Water Resources Research, 33(2): 309–319.

Wilson, J. and Gallant, J. (2000). Terrain analysis: Principle and applications. New York: Wiley & Sons.

 

Runtime: 1:06 (Pause video at 1:06. The content will resume on the following page.)