[GRASS-user] [GRASSLIST:1081] Sediment dispersal modeling

[Matthew Perry]

Hey folks,

  I'm working on a simple model for ocean floor sediment dispersal
from rivers. The basics are:

 - We have sediment outputs at point locations representing the pour point.
 - We want to "move" that sediment outward using something like a cost
distance function. The catch is that the output raster values, instead
of representing distance from the point, should represent a decaying
amount of the total sediment.
 - The total value of all raster cells in the sediment "plume" should
add up to roughly the total sediment output at the pour.
 - The total count of the sediment plume cells should be proportional
to the amount of sediment at the pour point.

It is a very simplistic model in that it doesn't take into account
currents and is only 2D but, for now, this is sufficient for the scale
we're working at.

We have looked at a few functions such as r.cost and r.spread but
neither seem to get us any closer to the outputs we're looking for.
Seeded region-growing (using r.mapcalc) and cellular automata seem
like they might also be appropriate tools but no luck so far.

Does anyone have any experience doing this sort of modelling in GIS
(GRASS or otherwise)? Any thoughts on a combination of techniques that
might yield the results I outlined?

Thanks for the input,
-- 
Matt Perry
perrygeo at gmail.com
http://www.perrygeo.net