[GRASS-user] region settings and wx display

[Nikos Alexandris]

* Tyler Smith <tyler at plantarum.ca> [2015-04-13 16:43:05 -0400]:

> Hi,
> 
> I've just spent an hour fighting with setting the region in GRASS 7.
> Finally I discovered that the display region and computational region
> are now independent. Is there a way to have the computational region
> automatically set to the display region, or do we now have to explicitly
> link them each time one or the other changes? If there's no way to link
> them automatically, is there a way to 'set computational region extent
> from display' from the command line?

Hi Tyler,

I don't think something has been changed. Computational region (extent +
resolution) was always a GRASS core concept. And the "display" region
(using your "term") was always different, meaning, zoom in/out and 
pan-ing maps in a display never altered the actual region extent and
resolution.

In the newer GUI there is a nice button for this, right after the
classic button "Zoom to selected map layer(s)" which is, of course,
labeled "Zoom to computational region extent".

The other relevant nice feature is to activate the "Show comp. extent"
in the bottom bar (in any wx Map Display window).

What else is there? After playing with a map in a wx Map Disaply window,
there are a few options "Set computational region from...".  Well, not
something that you wouldn't know about. I just mention them for the sake
of completeness.

All in all, I don't think there is a way to link automatically any
change in the display only (zoom actions, panning) with the actual
computational region.  If there is, I'd be happy to learn something new.
In fact, I don't think it would be smart. That is, I am used to it,
so maybe I am just too blind to see in another way. The user has to know
when he wants to change the computational region's extent, which will be
the extent of the output of *any* raster operation.

Nikos