[GRASS-user] band combinations using GRASS

GRASS GRASS user
1

Dear all,
I’m working with r.composite to create a natural color band combination using Landsat 8 image. The result is a very dark image, so I would like to know if there’s any way to improve it. I’m using GRASS 6.X and also GRASS 7.

Thanks in advance,

···

–
Josep Sitjar Suñer
Tècnic SIG / Servei de Sistemes d’Informació Geogràfica i Teledetecció

Universitat de Girona
SIGTE

Pl. Ferrater Mora 1
17071 Girona
Tel +34 972 418 039 (7026 intern)
josep@sigte.udg.edu

http://www.sigte.udg.edu
Twitter http://twitter.com/SIGTE_UDG

2

Hi Josep,

The images probably need a ‘Histogram Stretch’ using ‘r.colors’ use the ‘grey’ (color) and tick Histogram Stretch’ but make sure you set ‘g.region’ to the full image first otherwise it wont work.

Paul Shapley

···

On 10 December 2015 at 11:03, Josep Sitjar <josep@sigte.udg.edu> wrote:

Dear all,
I’m working with r.composite to create a natural color band combination using Landsat 8 image. The result is a very dark image, so I would like to know if there’s any way to improve it. I’m using GRASS 6.X and also GRASS 7.

Thanks in advance,

–
Josep Sitjar Suñer
Tècnic SIG / Servei de Sistemes d’Informació Geogràfica i Teledetecció

Universitat de Girona
SIGTE

Pl. Ferrater Mora 1
17071 Girona
Tel +34 972 418 039 (7026 intern)
josep@sigte.udg.edu

http://www.sigte.udg.edu
Twitter http://twitter.com/SIGTE_UDG

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

–

Paul J. Shapley MSc CGeog (GIS) FRGS

3

Hi Josep,

My apologies but i should have read your email thoroughly. Please check the link below hope this helps you.

http://www.paulshapley.com/2014/04/processing-landsat-8-bands-in-grass-gis.html

Regards,

Paul Shapley

···

On 10 December 2015 at 11:03, Josep Sitjar <josep@sigte.udg.edu> wrote:

Dear all,
I’m working with r.composite to create a natural color band combination using Landsat 8 image. The result is a very dark image, so I would like to know if there’s any way to improve it. I’m using GRASS 6.X and also GRASS 7.

Thanks in advance,

–
Josep Sitjar Suñer
Tècnic SIG / Servei de Sistemes d’Informació Geogràfica i Teledetecció

Universitat de Girona
SIGTE

Pl. Ferrater Mora 1
17071 Girona
Tel +34 972 418 039 (7026 intern)
josep@sigte.udg.edu

http://www.sigte.udg.edu
Twitter http://twitter.com/SIGTE_UDG

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

–

Paul J. Shapley MSc CGeog (GIS) FRGS

4

Dear Paul and Manfred,
thanks for you interest. It works.

According to your indications, I’ve applied a greyscale equalisation to each band (using r.colors) previous to the band combination. And the result is perfect.

Thanks,

···

Josep Sitjar Suñer
Tècnic SIG / Servei de Sistemes d’Informació Geogràfica i Teledetecció

Universitat de Girona
SIGTE

Pl. Ferrater Mora 1
17071 Girona
Tel +34 972 418 039 (7026 intern)
josep@sigte.udg.edu

http://www.sigte.udg.edu
Twitter http://twitter.com/SIGTE_UDG

El 10/12/15 a les 14:03, Paul Shapley ha escrit:

Hi Josep,

The images probably need a ‘Histogram Stretch’ using ‘r.colors’ use the ‘grey’ (color) and tick Histogram Stretch’ but make sure you set ‘g.region’ to the full image first otherwise it wont work.

Paul Shapley

On 10 December 2015 at 11:03, Josep Sitjar <josep@sigte.udg.edu> wrote:

Dear all,
I’m working with r.composite to create a natural color band combination using Landsat 8 image. The result is a very dark image, so I would like to know if there’s any way to improve it. I’m using GRASS 6.X and also GRASS 7.

Thanks in advance,

–
Josep Sitjar Suñer
Tècnic SIG / Servei de Sistemes d’Informació Geogràfica i Teledetecció

Universitat de Girona
SIGTE

Pl. Ferrater Mora 1
17071 Girona
Tel +34 972 418 039 (7026 intern)
josep@sigte.udg.edu

http://www.sigte.udg.edu
Twitter http://twitter.com/SIGTE_UDG

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

–

Paul J. Shapley MSc CGeog (GIS) FRGS

5

On Thu, Dec 10, 2015 at 2:09 PM, Paul Shapley <p.shapley@gmail.com> wrote:

Hi Josep,

My apologies but i should have read your email thoroughly. Please check the
link below hope this helps you.

http://www.paulshapley.com/2014/04/processing-landsat-8-bands-in-grass-gis.html

Another option is to use
https://grass.osgeo.org/grass70/manuals/i.colors.enhance.html

For an example, see e.g.

http://courses.neteler.org/processing-landsat8-data-in-grass-gis-7/
--> 7. Natural color view (RGB composite)

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