[GRASS-user] extract drainage in the right direction

Hi All,

There is some methodology where it is possible extract the drainage network and maintain the correct graph orientation? I verified that the operation of the extracted drainage with “flow accumulation” command and converted to vector does not represent the correct way that water runs along the river, some pieces are in the opposite direction.

Thanks in advance,

Marcello Benigno B. de Barros Filho
Prof. do Curso Superior de Tecnologia em Geoprocessamento - IFPB
Mestre em Ciências Geodésicas e Tecnologias da Geoinformação - UFPE
http://profmarcello.blogspot.com
http://about.me/marcello.benigno

Hi,

On Tue, Jan 24, 2012 at 1:24 PM, Marcello Benigno <benigno.marcello@gmail.com> wrote:

Hi All,

There is some methodology where it is possible extract the drainage network and maintain the correct graph orientation?

Regrettably, I cant say for sure, but I would be surprised if the vector stream/drainage network output from r.stream.extract did not orientate vector directions downstream properly. http://grass.osgeo.org/wiki/GRASS_AddOns#r.stream.extract

Mark

On Tue, Jan 24, 2012 at 8:03 PM, Mark Seibel <mseibel@gmail.com> wrote:

Hi,

On Tue, Jan 24, 2012 at 1:24 PM, Marcello Benigno
<benigno.marcello@gmail.com> wrote:

Hi All,

There is some methodology where it is possible extract the drainage
network and maintain the correct graph orientation?

Regrettably, I cant say for sure, but I would be surprised if the vector
stream/drainage network output from r.stream.extract did not orientate
vector directions downstream properly.
http://grass.osgeo.org/wiki/GRASS_AddOns#r.stream.extract

Yes, the stream lines in the vector output of r.stream.extract are
directed downstream.

Markus M

thanks for the quick response,

Is there any way to run this script in a non compiled version? My grass version was installed via apt-get and I don´t know if it’s a good idea to keep two versions in the same computer, is it better uninstall the previous one?

´s


Marcello Benigno B. de Barros Filho
Prof. do Curso Superior de Tecnologia em Geoprocessamento - IFPB
Mestre em Ciências Geodésicas e Tecnologias da Geoinformação - UFPE
http://profmarcello.blogspot.com
http://about.me/marcello.benigno