Re: [GRASS-user] Elevation profile from intersecting shapefiles‏

[Hamish]

georgew wrote:
> Hamish, please forgive my ignorance but I am not sure what you mean.
> As far as I know g.region is the means to change the resolution,

correct,

> whether through the command line or the GUI. Can you please explain how
> to access and change the computational region settings.

I was talking about when using it from the GUI.

from the command line the display (d.mon) resolution is the computation
region.


in the GUI there are two: the active display region(+resolution) and the
computational one. What you see in the display window(s) is independent
of what's in the $MAPSET/WIND file. That WIND(ow) file holds the region
which will be used by any modules running.  The reason for all this
confusion is that you can have multiple GUI display windows open at the
same time, each independently zoomed to a different area and set at a
different resolution (for a visual display there's no point at being at a
higher resolution than you can see). Multiple displays would need multiple
WIND files but the processing module (eg v.to.rast) wouldn't know which
was the appropriate one to use.  Thus computational region refers to what
is stored in the mapset's WIND file.

(sorry gui programmers if I have made small mistakes in that)


In gis.m, from the Map Display window if you click on the magnifying glass
icon (with the map) you get a pulldown menu. the last item is "set computational region extents to match display".

also in the GIS manager menu there is Config->Region. In that is "Display
region settings"* and "Change region settings" which brings up the
g.region GUI as if you were running it at the command prompt.

[*] perhaps badly worded, nothing to do with the Map Display- it prints
the current computational region to the output window.


A symptom of the computational region being way out of whack compared to
your display region is that you see the result as a series of huge blocks
(computational resolution is too coarse), or in the other direction the
resolution is so fine that takes ages to load. YMMV


hope it helps,
Hamish