[GRASS-user] r.drain documentation

[Maris Nartiss]

Hi,
You are right - r.drain will NOT give sane results at region boundary.
Here is snippet from filldir.c:107:
/* determine the flow direction in each cell.  On outer rows and columns
 * the flow direction is always directly out of the map */

It's a questionable what action r.drain should take if draining
process reaches map/region edge and there are reasonable arguments
that support current behaviour.  Definitely it must be reflected in
documentation and probably there could be printed some warning if
draining process fails over the edge :)

Maris.

2008/2/16, stefano negri <ste.negri.liste at gmail.com>:
> Thanks for your answers Eric and Hamish.
> I had already made sure with d.rast.num and I have double checked now on a
> "toy" map (a slope on a 100x100 grid): even if there are lower value cells
> beside a border cell, it won't move from there.
> Stefano.
>