[GRASSLIST:10644] Re: ARC FLOWDIRECTION vs GRASS

[Hamish]

> Some examples in GRASS see man pages for each command
> 
> 1. simplest case of the D8 flow direction, stored in new raster dir_d8 :
> r.fill.dir in=elev_meters elev=e_filled direction=dir_d8 
> 
> note that direction can be in the form of 0-360 or 1-8
> 
> 2. example of the D-INF algorithm (vector output stored in new vector
> flow) r.flow elevin=e_filled aspin=aspect flout=flow


be sure to visualize with d.rast.arrow too (version in grass 6.1-cvs).

also you might want to check out the (somewhat redundant in hindsight) 
dominant_dir.m and calc_terraflow_dir.m scripts on the Wiki add-ons
page for reducing MFD to D-8.
 http://grass.gdf-hannover.de/twiki/bin/view/GRASS/GrassAddOns#Raster_add_ons


Hamish