Topographic Ruggedness Index (TRI)

General discussion of Roughness

The topographic ruggedness index (TRI) was developed by Riley et al. (1999) to express the amount of elevation difference between adjacent cells of a DEM.  It calculates the difference in elevation values from a center cell and the eight cells immediately surrounding it. Then it squares each of the eight elevation difference values to make them all positive, sums them, and takes the square root.

GDAL recommends the Riley method for terrestrial cases, and Wilson for bathymetric.

Can be done:

Comparison of TRI with Various Programs

Improved parmeter SSR: Sebastiano Trevisani, Giordano Teza, & Peter L. Guth. (2023). Hacking the topographic ruggedness index.

See Rugosity, TPI,

Last revision 3/5/2023