[GRASS-user] Parallel GRASS jobs .....

The computational region (i.e., not the display region in the GUI) is the rectangular section of the world where GIS operations take place. With a few exceptions, all reads/writes to maps take place only within the region. You can set the region extents and resolution in many ways using g.region. You can also save region definitions to disk and call them as needed. For example, you could have a “north” and a “south” saved region and set map operations to alternately work in each of these using g.region region=north or g.region region=south.

Please look over the g.region manual and the general GRASS help for more information on regions. The docs are pretty good.

···

Sylvain

2012/11/28 Daniel Lee <lee@isi-solutions.org>

Hi there,

I do this too and the standard methodology for me is to leave the resolution the same and change the region’s borders. Take a look at the manual of g.region for guides on this, but let’s say I’ve got the following:

GRASS 6.4.3svn (EPSG4326_WGS84_ll):~ > g.region -g
n=63
s=-63
w=95
e=180
nsres=1.10020395685734e-05
ewres=1.10020399076346e-05
rows=11452422
cols=7725840
cells=88479579984480

Then to reduce the region’s size I’d do e.g.:
g.region n=50 s=-50 w=100 e=110

That would “shrink” my region down to the area that I’m interested in.

HTH!
Daniel

2012/11/28 Andranik Hayrapetyan <andranik.h89@gmail.com>

I have been trying something like this some time ago, but I could not define region of a mapset as chunk of the whole region.

Is g.region the right tool for this task?
If it is not difficult for you, can you, please, explain the process of doing " define the region of each mapset as a chunk of the whole region " a bit more detailed.

On Wed, Nov 28, 2012 at 1:56 PM, Sylvain Maillard <sylvain.maillard@gmail.com> wrote:

Hi,

for this approach, the best would be to
(before the multi-process job)

  • put your map into the PERMANENT mapset

(for each process in parallel)

  • make a new mapset for each process
  • define the region of each mapset as a chunk of the whole region
  • make your calculation

(once the process competed)

  • put together all the results (eg, with r.patch)

Sylvain


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


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

On Wed, Nov 28, 2012 at 4:25 PM, Michael Barton <Michael.Barton@asu.edu> wrote:

The computational region (i.e., not the display region in the GUI) is the
rectangular section of the world where GIS operations take place.

For this, see also here:
http://grasswiki.osgeo.org/wiki/Computational_region

Markus

Dear all,

Thank you very very much for your help!!!
I did it!

Daniel , your detailed explanations were very useful, thank you!
P.S. I am using the GUI just to clearly understand the procedure. Now I will try to make scripts that will do this job.

Regards,
Andranik

On Thu, Nov 29, 2012 at 2:46 AM, Markus Neteler <neteler@osgeo.org> wrote:

On Wed, Nov 28, 2012 at 4:25 PM, Michael Barton <Michael.Barton@asu.edu> wrote:

The computational region (i.e., not the display region in the GUI) is the
rectangular section of the world where GIS operations take place.

For this, see also here:
http://grasswiki.osgeo.org/wiki/Computational_region

Markus

Just one more question.

Now that I have, for example, 4 mapsets with different parts of the main map, and the calculation is done, how can I “see” this parts of map from one mapset (e.g. from PERMANENT) , to gather them together with r.patch ?

Is there a way to do this without exporting maps from each mapset and then importing them again into one mapset?

May be there is a way to change permissions so that PERMANENT could see all maps in other mapsets?

On Thu, Nov 29, 2012 at 11:36 AM, Andranik Hayrapetyan <andranik.h89@gmail.com> wrote:

Dear all,

Thank you very very much for your help!!!
I did it!

Daniel , your detailed explanations were very useful, thank you!
P.S. I am using the GUI just to clearly understand the procedure. Now I will try to make scripts that will do this job.

Regards,
Andranik

On Thu, Nov 29, 2012 at 2:46 AM, Markus Neteler <neteler@osgeo.org> wrote:

On Wed, Nov 28, 2012 at 4:25 PM, Michael Barton <Michael.Barton@asu.edu> wrote:

The computational region (i.e., not the display region in the GUI) is the
rectangular section of the world where GIS operations take place.

For this, see also here:
http://grasswiki.osgeo.org/wiki/Computational_region

Markus

Just one more question.

Now that I have, for example, 4 mapsets with different parts of the main

map, and the calculation is >done, how can I "see" this parts of map from
one mapset (e.g. from PERMANENT) , to gather them >together with r.patch ?

Is there a way to do this without exporting maps from each mapset and then

importing them again >into one mapset?

May be there is a way to change permissions so that PERMANENT could see all

maps in other mapsets?

see g.mapsets - Modifies the user's current mapset search path. [1]

[1] http://grass.osgeo.org/grass64/manuals/g.mapsets.html

-----
best regards
Helmut
--
View this message in context: http://osgeo-org.1560.n6.nabble.com/Parallel-GRASS-jobs-tp5019245p5019510.html
Sent from the Grass - Users mailing list archive at Nabble.com.

Thank you, it solved all my problems!

On Thu, Nov 29, 2012 at 12:58 PM, Helmut Kudrnovsky <hellik@web.de> wrote:

Just one more question.

Now that I have, for example, 4 mapsets with different parts of the main
map, and the calculation is >done, how can I “see” this parts of map from
one mapset (e.g. from PERMANENT) , to gather them >together with r.patch ?

Is there a way to do this without exporting maps from each mapset and then
importing them again >into one mapset?

May be there is a way to change permissions so that PERMANENT could see all
maps in other mapsets?

see g.mapsets - Modifies the user’s current mapset search path. [1]

[1] http://grass.osgeo.org/grass64/manuals/g.mapsets.html


best regards
Helmut

View this message in context: http://osgeo-org.1560.n6.nabble.com/Parallel-GRASS-jobs-tp5019245p5019510.html
Sent from the Grass - Users mailing list archive at Nabble.com.


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

On Thu, Nov 29, 2012 at 10:43 AM, Andranik Hayrapetyan
<andranik.h89@gmail.com> wrote:

Thank you, it solved all my problems!

Excellent!
Please consider to add a bit of explanations in the
Wiki for the next user (either yourself or suggest here what
to add in the Wiki). Then the gained knowledge doesn't
get lost in the email archive.

thanks
Markus

Ok, I will make a script, that will handle all this operations, and will write here a step by step explanation of this process.

On Thu, Nov 29, 2012 at 1:53 PM, Markus Neteler <neteler@osgeo.org> wrote:

On Thu, Nov 29, 2012 at 10:43 AM, Andranik Hayrapetyan
<andranik.h89@gmail.com> wrote:

Thank you, it solved all my problems!

Excellent!
Please consider to add a bit of explanations in the
Wiki for the next user (either yourself or suggest here what
to add in the Wiki). Then the gained knowledge doesn’t
get lost in the email archive.

thanks
Markus