[GRASS-user] Pixels values ​​are changed when the layer is exported to vector (column "value" in attribute tables)

GRASS GRASS user
1

Hello All,

After creating my stream network with the command r.stream.order, I converted the result to vector, with the command r.to.vect, something wrong happened… the values ​​that were associated with the pixels appear exchanged for some features (e.g., in the raster the pixel value is “1” and in the vector appears “2”). I wonder if my procedure is wrong or there might be some problem related to my data (SRTM) when even a possible GRASS bug.

The link below shows the two overlying layers (problem.png) and it is possible to find some places where the values ​​of the raster layer (raster.png) does not correspond to the values ​​of the vector layer (vector.png).

http://ge.tt/4FR2l7H?c

Could anyone help me?

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
Doutorando em Tecnologia Ambiental e Recursos Hídricos - UFPE
http://profmarcello.blogspot.com
http://about.me/marcello.benigno

2

Any solution? I also tried using the r.thin but keep having the same problem

Thanks in advance,

2012/5/2 Marcello Benigno <benigno.marcello@gmail.com>

Hello All,

After creating my stream network with the command r.stream.order, I converted the result to vector, with the command r.to.vect, something wrong happened… the values ​​that were associated with the pixels appear exchanged for some features (e.g., in the raster the pixel value is “1” and in the vector appears “2”). I wonder if my procedure is wrong or there might be some problem related to my data (SRTM) when even a possible GRASS bug.

The link below shows the two overlying layers (problem.png) and it is possible to find some places where the values ​​of the raster layer (raster.png) does not correspond to the values ​​of the vector layer (vector.png).

http://ge.tt/4FR2l7H?c

Could anyone help me?

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
Doutorando em Tecnologia Ambiental e Recursos Hídricos - UFPE
http://profmarcello.blogspot.com
http://about.me/marcello.benigno

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

3

On Thu, May 3, 2012 at 10:07 PM, Marcello Benigno
<benigno.marcello@gmail.com> wrote:

Any solution? I also tried using the r.thin but keep having the same problem

If you are using GRASS 6.4.1, this is a bug in v.out.ogr that has been
fixed in 6.4.2.

Markus M

Thanks in advance,

2012/5/2 Marcello Benigno <benigno.marcello@gmail.com>

Hello All,

After creating my stream network with the command r.stream.order, I
converted the result to vector, with the command r.to.vect, something wrong
happened... the values that were associated with the pixels appear exchanged
for some features (e.g., in the raster the pixel value is "1" and in the
vector appears "2"). I wonder if my procedure is wrong or there might be
some problem related to my data (SRTM) when even a possible GRASS bug.

The link below shows the two overlying layers (problem.png) and it is
possible to find some places where the values of the raster layer
(raster.png) does not correspond to the values of the vector layer
(vector.png).

http://ge.tt/4FR2l7H?c

Could anyone help me?

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
Doutorando em Tecnologia Ambiental e Recursos Hídricos - UFPE
http://profmarcello.blogspot.com
http://about.me/marcello.benigno

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

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