Hi Markus You are right. Thanks for your comments. In fact I don´t thougth on null cell between Source and Target, and agree that extent influences one archive or not a real least cost path solution.
Cheers miltinho 2012/12/27, Markus Metz <markus.metz.gisw...@gmail.com>: > On Wed, Dec 26, 2012 at 10:01 PM, Milton Cezar Ribeiro > <miltinho.astrona...@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. > > Ah, you are right, if the input is output from r.cost, the cost > directions should be used. Depending on the input data and the region > extents, the least cost path found may not be the real least cost > path, but there should be one solution. > > There are situations where there is no connection between source and > target if source and target are separated by NULL cells and no NULL > cost is specified to r.cost. > > Markus M >> >> Happy new year! >> >> miltinho >> >> 2012/12/23, Markus Metz <markus.metz.gisw...@gmail.com>: >>> On Sun, Dec 23, 2012 at 7:07 PM, Milton Cezar Ribeiro >>> <miltinho.astrona...@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 - m...@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 - m...@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@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user