How to measure topographic roughness irrespective of slope in ArcGIS? I have used many methods to generate roughness layers, including TRI, VRM (which is supposed to be less correlated with slope), slope aspect index, slope variance, slope standard deviation etc.
So far, all of the output layers are extremely similar to each other and to my slope layer. They do not seem to be clearly differentiating between areas of steep and rugged terrain and those which are steep but smooth.
How can I generate a roughness layer which is not so dependent on slope?