[GRASS-user] r.composite changing pixel resolution?

José María Michia jose.maria.michia at gmail.com
Fri Feb 13 03:54:37 EST 2009


Ops! Sorry, I used the translator incorrectly!

Corrections:

> To check the values of the active region, use the following command:
>
> g.region -p
>
> To set the values of the active region to the same values as their
> input maps, use:
>
> g.region -p rast=name_of_raster_map
>
> To check the values of some map, use:
>
> r.info map=name_of_raster_map

And an important note: I'm not sure if this information is applicable
using the plugin in QGIS.

Please, sorry again, I make many mistake but with the best intentions!

Saludos

2009/2/13 José María Michia <jose.maria.michia en gmail.com>:
> Hi Tim and all!
>
> 2009/2/13 Tim Holland <timothyholland en gmail.com>:
>>
>> Dear all,
>>
>> I am new to both Grass and this forum, so apologies in advance for something
>> which is likely a simple mistake or oversight on my part (but I have
>> searched the forum and can't seem to find an answer).
>>
>> I am trying to create RGB-composite images from various sets of Landsat
>> bands (3,2,1 or 4,5,3).  When I try to do this using r.composite, the
>> resulting raster file has a far courser pixel resolution than the original
>> images (it looks like it is scaling up by a factor of 12 - so 30m x 30m
>> pixels become 360m x 360m).  I can't see anything in the r.composite manual
>> that suggests why this would be happening.
>>
>> If it is relevant, I am also using i.landsat.rgb to balance the colours
>> before I am using the r.composite.  Also, I am using Grass 6.3, and running
>> it through the plugin on QGIS 0.11.0.
>
>
> When you run a command that produces a new map, usually the new map
> has the size and resolution of the active region, not far and the
> resolution of input maps.
>
> To check the values of the active region, use the following command:
>
> g.region-p
>
> To set the values of the active region to the same values as their
> input maps, use:
>
> RAST g.region P = name_of_raster_map
>
> To check the values of some map, use:
>
> r.info map name_of_raster_map =
>
> I hope this helps!
>
> Saludos
> José María
>


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