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

Sun Dec 30 14:44:57 PST 2012

Hi Markus

I am using this commands.

r.cost -k input=friction_landuse_roads output=cost_map
start_points=map_source_pt stop_points=map_target_pt --o
r.drain input=cost_map output=drain_map vector_points=map_target_pt --o

I have not a direction map, and as for other source-target-friction
maps everything works fine without direction map I thougth that this
should work for all.

If you have the chance, please run the command and take a look that
the drain line finish on right border.

best wishes

miltinho

2012/12/30, Markus Metz <markus.metz.giswork at gmail.com>:
> On Sun, Dec 30, 2012 at 8:59 PM, Milton Cezar Ribeiro
> <miltinho.astronauta at gmail.com> wrote:
>> Hi Rashad
>>
>> I tested with the trunk svn, but apparently it still not worked to me.
>> Are you able to test with my datased?
>>
>> https://www.yousendit.com/download/UW16RE9zTkxlM1JBSXNUQw
>
> What are the commands you used? I found
> r.drain input=custo_aux_cost output=custo_aux_cost_drain
> vector_points=map_target_pt
>
> You need to also provide a direction map with the indir option of r.drain.
>
> Markus M
>
>>
>> Thanks!
>>
>> miltinho
>>
>> 2012/12/27, Mohammed Rashad <mohammedrashadkm at gmail.com>:
>>> Hi Milton,
>>>
>>> I think this fix will solve the problem[0]. For elevation data there
>>> might
>>> be cases where no path exists ie, only single pixel is the selected path.
>>> I
>>> had tested it by myself and it worked.
>>>
>>> Please apply the patch and let me know.
>>>
>>> If any problem comes in compilation or doing r.drain let me know. It
>>> will
>>> be great if you can share the test data you are using in case not
>>> working
>>> after applying the patch
>>>
>>> [0] http://trac.osgeo.org/grass/attachment/ticket/1840/r.drain.diff
>>> [1] http://trac.osgeo.org/grass/attachment/ticket/1840/drain.c
>>>
>>>
>>> On Thu, Dec 27, 2012 at 2:31 AM, Milton Cezar Ribeiro <
>>> miltinho.astronauta at gmail.com> wrote:
>>>
>>>> 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!
>>>>
>>>> miltinho
>>>>
>>>> 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
>>>> >
>>>>
>>>>
>>>> --
>>>> Miltinho - mcr at rc.unesp.br
>>>> Laboratório de Ecologia Espacial e Conservação - LEEC
>>>> Depto de Ecologia - UNESP - Rio Claro
>>>> Av. 24A, 1515- Bela Vista
>>>> 13506-900 Rio Claro, SP, Brasil
>>>>
>>>> Fone: +55 19 3526-9647 (office)  19 3526-9680 (lab)
>>>> Cel: 19 9853-3220 / 19 9853-5430
>>>>
>>>> Depto Ecologia http://www.rc.unesp.br/ib/ecologia/
>>>>
>>>> PG ECO & BIODIV
>>>> http://www.rc.unesp.br/ib/ecologia/posbiodiversidade/index.php
>>>>
>>>> CV
>>>> http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792988H6&mostrarNroCitacoesISI=true&mostrarNroCitacoesScopus=true
>>>>
>>>> Google citations http://scholar.google.com/citations?user=OWX_2eAAAAAJ
>>>> _______________________________________________
>>>> grass-user mailing list
>>>> grass-user at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/grass-user
>>>>
>>>
>>>
>>>
>>> --
>>> Regards,
>>>    Rashad
>>>
>>
>>
>> --
>> Miltinho - mcr at rc.unesp.br
>> Laboratório de Ecologia Espacial e Conservação - LEEC
>> Depto de Ecologia - UNESP - Rio Claro
>> Av. 24A, 1515- Bela Vista
>> 13506-900 Rio Claro, SP, Brasil
>>
>> Fone: +55 19 3526-9647 (office)  19 3526-9680 (lab)
>> Cel: 19 9853-3220 / 19 9853-5430
>>
>> Depto Ecologia http://www.rc.unesp.br/ib/ecologia/
>>
>> PG ECO & BIODIV
>> http://www.rc.unesp.br/ib/ecologia/posbiodiversidade/index.php
>>
>> CV
>> http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792988H6&mostrarNroCitacoesISI=true&mostrarNroCitacoesScopus=true
>>
>> Google citations http://scholar.google.com/citations?user=OWX_2eAAAAAJ
>

-- 
Miltinho - mcr at rc.unesp.br
Laboratório de Ecologia Espacial e Conservação - LEEC
Depto de Ecologia - UNESP - Rio Claro
Av. 24A, 1515- Bela Vista
13506-900 Rio Claro, SP, Brasil

Fone: +55 19 3526-9647 (office)  19 3526-9680 (lab)
Cel: 19 9853-3220 / 19 9853-5430

Depto Ecologia http://www.rc.unesp.br/ib/ecologia/

PG ECO & BIODIV http://www.rc.unesp.br/ib/ecologia/posbiodiversidade/index.php

CV http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792988H6&mostrarNroCitacoesISI=true&mostrarNroCitacoesScopus=true

Google citations http://scholar.google.com/citations?user=OWX_2eAAAAAJ