[GRASS-user] Region Definition in GRASS

[Milton Cezar Ribeiro]

Pedro,

If you run a r.mapcalc, the extent and resolution will follow the current
region. So, check g.region -p before run r.mapcalc. You can use g.region
rast=MapLandsat to set the current region to use MapLandsat dimensions as
reference. After you can reset your extention and resolution using g.region
-d . By the way, read g.region --help.

best
milton

2010/2/5 Pedro Roma <pedroroma1982 at gmail.com>

>
> Ok but for instance. If my region is defined with a Spatial Resolution of
> 1kilometer and, if I do some r.mapcalc with two LANDSAT images, the output
> image will have which one of the resolutions? the Region or the 2 landsat
> images?
>
> Thank you Glynn for the overview. And thank you Hamish for the weblinks
>
>
> On Thu, Feb 4, 2010 at 7:14 PM, Glynn Clements <glynn at gclements.plus.com>wrote:
>
>>
>> Pedro Roma wrote:
>>
>> > I'm a kind of a new GRASS user and I'm a bit lost on regarding
>> something.
>> > REGION (or spatial extent).
>> > For instance the Location North-Carolina. When the location was created
>> a
>> > certain extent, projkection a Spatial Resolution was defined. But,
>> inside
>> > this location there is a lot of data with different extent and regional
>> > cover. And, inside GRASS I can re-define region properties (g.region)
>> and
>> > use a certain data to define region. And, it's possible to have a region
>> > with a small extent than a vectorial that exists in the Location.
>> > My question is, what is the region and what is its purpose? Because I
>> don't
>> > see any impact of region over my image/data processing or image
>> > visualization. Or is it?
>>
>> The region is mostly used for raster processing and graphical display.
>>
>> Most commands which read or write raster maps will use the bounds and
>> resolution from the current region. Any input maps will be cropped,
>> padded and/or resampled according to the region settings.
>>
>> Display commands translate geographic or cartographic coordinates to
>> display coordinates such that the current region just fits inside the
>> display window.
>>
>> Vector commands are normally unaffected by the current region.
>>
>> --
>> Glynn Clements <glynn at gclements.plus.com>
>>
>
>
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