[GRASS-user] Creation and managing Location/Mapset

[Nikos Alexandris]

Luisa Peña:
> > 1- Should I create 1 Location with 4 different mapsets (for each of
> > the considered scales)? Or should I use 1 location, one mapset and 4
> > different regions?

Luís Ferreira wrote:
> one location if all the analysis will be done with one coordinate system
> one mapset = one region, one resolution

Of course you can work with material of different geospatial extent/resolution 
on the same mapset. It's just that you have to pay attention when it comes to 
raster computations.

Note also that most vector modules are _not_ limited by the extent/resolution 
of the _computational_ region.

> so, perhaps, is better you to use four different mapsets (four levels)

I would think of using several map sets based on "what" is the question to be 
answered. Something like a thematic sorting. For example an ndvi mapset. 
Combine your "questions to be answered" with your "scale" levels (if you want 
to _not_ think all the time about the extent and the resolution) and you could 
go for, let's say "ndvi_local" , "ndvi_national", "indexA_local", 
"indexA_national", etc.

Finally an export mapset could be useful to drag-in all the maps you want to 
export (at a single step using some script for example?).

> > 2- How can I define a region that is not a perfect square' Because in 
> > "Set Region" we have North, South, East and West Boundaries. And my 
> > regions are not perfect squares.

> A region don't need to be square. And you can use an analysis mask.
> Raster > Mask, or r.mask.

Or "r.mapcalc". I remember at least one occasion where "r.mask" did not work 
as expected. Don't know if this has been fixed.

Note that there might be some modules that ignore the MASK!

Cheers, Nikos