[GRASS-user] Perform resample a raster using another image as a reference for the process?

GRASS GRASS user
,
1

Hello , nice to say hello , I have 2 raster : A raster is 20 meters and another 30 meters in the same area. As I can do in QGIS for a resampling an image with reference to the other? and that the pixels are perfectly aligned ? I use a google translator ! Thank you very much Eddison

2

Eddison,

First align your region to the destination raster with 'g.region
raster=rastername'.
Then resample the other raster.

Laurent

2016-08-02 11:48 GMT-05:00 Eddison Araya <eddisonjose@gmail.com>:

Hello , nice to say hello , I have 2 raster : A raster is 20 meters and
another 30 meters in the same area. As I can do in QGIS for a resampling an
image with reference to the other? and that the pixels are perfectly aligned
? I use a google translator ! Thank you very much Eddison

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3

Hello thank you very much , you can put some screenshots of the process? Greetings and thanks Eddison

···

2016-08-02 11:13 GMT-06:00 Laurent C. <lrntct@gmail.com>:

Eddison,

First align your region to the destination raster with ‘g.region
raster=rastername’.
Then resample the other raster.

Laurent

2016-08-02 11:48 GMT-05:00 Eddison Araya <eddisonjose@gmail.com>:

Hello , nice to say hello , I have 2 raster : A raster is 20 meters and
another 30 meters in the same area. As I can do in QGIS for a resampling an
image with reference to the other? and that the pixels are perfectly aligned
? I use a google translator ! Thank you very much Eddison

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

4

Eddison wrote

Hello thank you very much , you can put some screenshots of the process?
Greetings and thanks Eddison

have a look at https://grass.osgeo.org/grass70/manuals/g.region.html

-a Align region to resolution
raster=name[,name,...] Set region to match raster map(s)

g.region -a raster=your_raster_you_want_align_to

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best regards
Helmut
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5

Eddison wrote:

Hello thank you very much , you can put some screenshots of the process?

* Helmut Kudrnovsky <hellik@web.de> [2016-08-02 12:21:17 -0700]:

have a look at https://grass.osgeo.org/grass70/manuals/g.region.html
-a Align region to resolution raster=name[,name,...]

Set region to match raster map(s)
g.region -a raster=your_raster_you_want_align_to

Also useful (to read and use): https://grass.osgeo.org/grass70/manuals/r.resample.html

Nikos

6

On Wed, Aug 3, 2016 at 12:44 AM, Nikos Alexandris
<nik@nikosalexandris.net> wrote:

Eddison wrote:

Hello thank you very much , you can put some screenshots of the process?

* Helmut Kudrnovsky <hellik@web.de> [2016-08-02 12:21:17 -0700]:

have a look at https://grass.osgeo.org/grass70/manuals/g.region.html
-a Align region to resolution raster=name[,name,...]

See also
https://grasswiki.osgeo.org/wiki/Computational_region

Set region to match raster map(s)
g.region -a raster=your_raster_you_want_align_to

Also useful (to read and use):
https://grass.osgeo.org/grass70/manuals/r.resample.html

For an overview, see also
https://grasswiki.osgeo.org/wiki/Interpolation

Markus

PS: I have now added the second link to all relevant manual pages

7

Hello thank you very much , then the command is as follows:

g.region -a -p raster=lsat5_1987_10 align=urban ?

regards

Eddison

···

2016-08-03 5:52 GMT-06:00 Markus Neteler <neteler@osgeo.org>:

On Wed, Aug 3, 2016 at 12:44 AM, Nikos Alexandris
<nik@nikosalexandris.net> wrote:

Eddison wrote:

Hello thank you very much , you can put some screenshots of the process?

have a look at https://grass.osgeo.org/grass70/manuals/g.region.html
-a Align region to resolution raster=name[,name,…]

See also
https://grasswiki.osgeo.org/wiki/Computational_region

Set region to match raster map(s)
g.region -a raster=your_raster_you_want_align_to

Also useful (to read and use):
https://grass.osgeo.org/grass70/manuals/r.resample.html

For an overview, see also
https://grasswiki.osgeo.org/wiki/Interpolation

Markus

PS: I have now added the second link to all relevant manual pages

8

Eddison wrote:

>>> Hello thank you very much , you can put some screenshots of the
>>> process?

Helmut Kudrnovsky:

>> have a look at https://grass.osgeo.org/grass70/manuals/g.region.html
>> -a Align region to resolution raster=name[,name,...]

See also
https://grasswiki.osgeo.org/wiki/Computational_region

>> Set region to match raster map(s)
>> g.region -a raster=your_raster_you_want_align_to

Nikos Alexandris:

> Also useful (to read and use):
> https://grass.osgeo.org/grass70/manuals/r.resample.html

Markus Neteler:

For an overview, see also
https://grasswiki.osgeo.org/wiki/Interpolation

PS: I have now added the second link to all relevant manual pages

Eddison Araya:

Hello thank you very much , then the command is as follows:
g.region -a -p raster=lsat5_1987_10 align=urban ?

Eddison, the command is as Helmut proposed in one of his first posts
(see below).

Essentialy, you want to set the extent of the region (within which
grass' raster modules will operate) to match a raster map's dimensions.

That is,

g.region raster=Your_Raster_Map

And, even more, you want to force the alignment of the extent to this
map. This is done by addin the -a flag:

g.region -a raster=Your_Raster_Map

That's it, nothing more.

Nikos

ps- Please, if you would like, keep bottom posting so as to to preserve flow of the
discussion.

9

Eddison wrote:

>>> Hello thank you very much , you can put some screenshots of the
>>> process?

Helmut Kudrnovsky:

>> have a look at https://grass.osgeo.org/grass70/manuals/g.region.html
>> -a Align region to resolution raster=name[,name,...]

See also
https://grasswiki.osgeo.org/wiki/Computational_region

>> Set region to match raster map(s)
>> g.region -a raster=your_raster_you_want_align_to

Nikos Alexandris:

> Also useful (to read and use):
> https://grass.osgeo.org/grass70/manuals/r.resample.html

Markus Neteler:

For an overview, see also
https://grasswiki.osgeo.org/wiki/Interpolation

PS: I have now added the second link to all relevant manual pages

Eddison Araya:

Hello thank you very much , then the command is as follows:
g.region -a -p raster=lsat5_1987_10 align=urban ?

Eddison, the command is as Helmut proposed in one of his first posts
(see below).

Essentialy, you want to set the extent of the region (within which
grass' raster modules will operate) to match a raster map's dimensions.

That is,

g.region raster=Your_Raster_Map

And, even more, you want to force the alignment of the extent to this
map. This is done by addin the -a flag:

g.region -a raster=Your_Raster_Map

That's it, nothing more.

Eddison, seems I was to fast (and writing out of memory) and your above
command is correct, I guess. The -a will align the region's extent, to,
well, as the manual explains, the resolution.

So, you'd need your `align=` part.

Nikos

10

2016-08-03 15:17 GMT-06:00 Nikos Alexandris <nik@nikosalexandris.net>:

Eddison wrote:

>>> Hello thank you very much , you can put some screenshots of the

>>> process?

Helmut Kudrnovsky:

>> have a look at https://grass.osgeo.org/grass70/manuals/g.region.html

>> -a Align region to resolution raster=name[,name,...]

See also

https://grasswiki.osgeo.org/wiki/Computational_region

>> Set region to match raster map(s)

>> g.region -a raster=your_raster_you_want_align_to

Nikos Alexandris:

> Also useful (to read and use):

> https://grass.osgeo.org/grass70/manuals/r.resample.html

Markus Neteler:

For an overview, see also

https://grasswiki.osgeo.org/wiki/Interpolation

PS: I have now added the second link to all relevant manual pages

Eddison Araya:

Hello thank you very much , then the command is as follows:

g.region -a -p raster=lsat5_1987_10 align=urban ?

Eddison, the command is as Helmut proposed in one of his first posts
(see below).

Essentialy, you want to set the extent of the region (within which
grass' raster modules will operate) to match a raster map's dimensions.

That is,

g.region raster=Your_Raster_Map

And, even more, you want to force the alignment of the extent to this
map. This is done by addin the -a flag:

g.region -a raster=Your_Raster_Map

That's it, nothing more.

Eddison, seems I was to fast (and writing out of memory) and your above
command is correct, I guess. The -a will align the region's extent, to,
well, as the manual explains, the resolution.

So, you'd need your `align=` part.

Nikos

Hello, thank you very much to all of you for your answers, for their
willingness to cooperate , very friendly. regards Eddison