Greetings
This may sound a very big and dense question but… I really need to figure a few things out. I’ve been using only one location/mapset so I’m not use to create, manage and define regions.
I’m doing a study for a certain region in Turkey. I’m doing this analysis for 4 different levels (National, Regional, county, city). For each level I will produce different indexes (simples map.calculators) using remote sensing images. Each of the of these scales will use different images (e.g. local will use Quickbird, national will use AVHRR) and each of them has different spatial extent. So, each reagion has a specific spatial extent and spatial resolution. I have an external vector that defines each one of this scales. So for instance, NDVI at county level will have a spatial resolution and extent different from the national since it uses different datasets.
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?
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.
Note. I will have only one user
Thank you for your time
Best regards
Luisa
For now these are my questions
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?
one location if all the analysis will be done with one coordinate system
one mapset = one region, one resolution
so, perhaps, is better you to use four different mapsets (four levels)
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.
Luís Ferreira
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
Hi Nikos and Luis
Thanks for your replies
I still have a few issues regarding this:
1- How can a region not to be a Square? If I have to set North/South/East/West boundaries?
2- In my case, my mask is a Vectorial. Can I use a vectorial as a mask?
Thank you once again
No dia 17 de Maio de 2010 23:44, Nikos Alexandris <nikos.alexandris@felis.uni-freiburg.de> escreveu:
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
Luisa Peña:
I still have a few issues regarding this:
1- How can a region not to be a Square? If I have to set
North/South/East/West boundaries?
By using a MASK will limit raster operations (within the MASK).
2- In my case, my mask is a Vectorial. Can I use a vectorial as a mask?
v.to.rast in=VectorMap out=RasterisedVectorMap use=value
r.mapcalc "MASK=RasterisedVectorMap"
Nikos
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