[GRASS-user] r.terraflow for cost path analysis

[Colin Wren]

A recent article published in the Journal of Archaeological Science
(http://dx.doi.org/10.1016/j.jas.2010.11.006) proposed a method where
hydrology models could be used on the product of a cost surface
analysis to create a network of paths (instead of just the one made
with r.drain -d). The flow accumulation map would represent the number
of cells in the map from which a least-cost path would pass through
that cell. ie. a flow accumulation of 100 means that 100 cells would
have a LCP that would pass through that cell. You could also calculate
mobility basins (like a watershed), etc.

This is great extension of cost surface analysis except that I don't
think it can be done in GRASS right now. r.cost and r.walk produce a
cumulative cost surface and a "flow" direction surface, but if I'm
right r.terraflow can't take them as inputs because it calculates
everything "in-house".

I was hoping someone could double-check my logic on this or perhaps
suggest an alternative hydrology module(s) which could take the
direction surface as an input instead of calculating everything from
the elevation surface.

Cheers,
Colin