[GRASS-user] r.drain problem when flow reach the border

Milton Cezar Ribeiro miltinho.astronauta at gmail.com
Wed Dec 26 13:01:21 PST 2012

Hi Mohamed and Markus

Mohamed, thanks for your reply, I will wait for a solution within GRASS :-)

Markus, thanks for your reply,. Sorry  but I disagree a tiny bit,
because is expected that between a source and target I will find a
solution with the Least Cost path. Do you think that is there any
situation where a least cost between source and target will not be
found? Maybe if other software provide the soluction, although is not
the bestest option, I prefere receive one complete output than a
broken one.

Happy new year!


2012/12/23, Markus Metz <markus.metz.giswork at gmail.com>:
> On Sun, Dec 23, 2012 at 7:07 PM, Milton Cezar Ribeiro
> <miltinho.astronauta at gmail.com> wrote:
>> Dear all,
>> I am running a least cost path analysis combining r.cost and r.drain.
>> But on some cases, when the least cost path between source and target
>> reach the border of my map, r.drain stop on that position, and target
>> point isn´t reached.
> This is correct because at the borders, the direction can not be
> determined, the path could lead out of the current region, you can not
> tell.
> Running on other softwares the algorithms the
>> source and target is connected using edges without problem.
> If in doubt, I would call it a bug in that other software.
>> Any hint are welcome.
> Try to expand the current region
> Markus M

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