[GRASS-user] Fastest way to merge raster images in GRASS...

Nikos Alexandris nik at nikosalexandris.net
Fri Aug 16 11:28:11 PDT 2013

Andranik Hayrapetyan wrote:

> Good day,

Good evening/night,

> I am very interested in finding the fastest way to merge raster images (or
> parts of an image) with GRASS.

r.patch ?

> Now I am using r.patch, but unfortunately it is very slow for my problem.

- GRASS-GIS version and Operating System please?
- How slow? How big is the region in which you are operating? ( check with 
g.region -p)

You can/should match the region to the extent of all the raster to-be-merged 
images, then r.patch, of course.

> Is there any other ways to merge raster data in GRASS?

Maybe r.mapcalc?

> Or may be it will be more fast to use GDAL functions directly? May be GDAL
> merge?

Sure, you can build "mosaics" using gdal utilities.  I guess you already have 
had a look at <http://www.gdal.org/gdal_merge.html>.

> Has anyone done experiments with this kind of issues?

r.patch always did/does its job inside GRASS.

Regards, Nikos

More information about the grass-user mailing list