[GRASS-user] Mosaic

GRASS GRASS user
1

Hi!

A newbie doubt: I have to make a mosaic with 2 satellite images (CBERS). The border values are “0”. What is the procedure? (the images are already on grass).

Raphael Saldanha
BRAZIL

2

On Fri, 2008-08-08 at 08:57 -0300, Raphael Saldanha wrote:

Hi!

A newbie doubt: I have to make a mosaic with 2 satellite images
(CBERS). The border values are "0". What is the procedure? (the images
are already on grass).

Raphael Saldanha
BRAZIL

Hi Raphael.

If your images are correctly georeferenced then you only need to use
r.patch or r.mapcalc.

Set the extent of the computational region with g.region first, for
example:
g.region rast=satimage1,satimage2 -pa

Then patch:
r.patch in=satimage1,satimage2 out=mosaic

Kind regards, Nikos.

3

On Fri, 2008-08-08 at 09:53 -0300, Raphael Saldanha wrote:

Hi Nikos!

Thanks for the advice!

So, I use this:

Set null values: > r.nul
Set region: > g.region
Create mosaic: > r.patch

Thanks!!!

On Fri, Aug 8, 2008 at 9:26 AM, Nikos Alexandris
<nikos.alexandris@felis.uni-freiburg.de> wrote:
        
        On Fri, 2008-08-08 at 08:57 -0300, Raphael Saldanha wrote:
        > Hi!
        >
        > A newbie doubt: I have to make a mosaic with 2 satellite
        images
        > (CBERS). The border values are "0". What is the procedure?
        (the images
        > are already on grass).
        >
        > Raphael Saldanha
        > BRAZIL
        
        Hi Raphael.
        
        If your images are correctly georeferenced then you only need
        to use
        r.patch or r.mapcalc.
        
        Set the extent of the computational region with g.region
        first, for
        example:
        g.region rast=satimage1,satimage2 -pa
        
        Then patch:
        r.patch in=satimage1,satimage2 out=mosaic
        
        Kind regards, Nikos.
        

[cc-ing to the list]

Raphael, it is not required to set any NULL values I think, except if
you need it for your own reasons to set NULL values.

Cheers, Nikos