Hi, all.

I'm trying to calculate Topographic Wetness Index with SAGA GIS.

I was wondering how exactly is catchment slope calculated in Catchment Area module (parallel)? I'm having hard time finding any documentation on slope calculation, that would make this clearer to me.

I'm worried that I'm using wrong type of slope when executing topographic wetness module.

Most of the literature related to TWI express TWI as Ln(a/tanB) where a is the spesific catchment area and tanB is the local slope. How does catchment slope, calculated here, correspond to this?

Last edit: Henri Riihimäki 2014-03-20