[GRASS-user] Raster Import

[Micha Silver]

On 06/12/2010 08:43 AM, Kyaw Moe Aung wrote:
> Dear List,
> I am new user for Grass GIS. I have some questions regarding Jpg or 
> tiff import. When I use r.in.gdal which created 3 separate files as 
> rgb. Then I use r.patch to combine rgb. After that i.point and 
What you probably want here is r.composite. It re-creates the colored 
raster.
> i.rectify. From this i have to digitize river, stream, road, etc. So 
> my question is as follow:
> Can i remove unrectified former 3 seperate rgb files?
Yes, after r.composite you can remove them.
> Is there any module to import without creating rgb because this 
> increase the memory usage? I have to import more than hundreds of 
> scanned Jpg, tiff.
Imported three-band tiffs will always create three separate rasters. But 
you can script this to loop thru your 100's of tiff's to import, 
recreate the colored raster, then delete the *.red, *.green and *.blue 
at each loop.
> Can i crop the imported image without using other image software such 
> as gimp or photoshop, etc?
Yes. Just set the grass region to the area you want, and run:
r.mapcalc cropped_raster=original_raster
That creates a copy of the original, cropped to the current region.

BTW, this can also be done in advance with gdal.
> Thanks for any hint
>
> -- 
> -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-
> U Kyaw Moe Aung, Staff Officer
> Planning & Statistics Division, Forest Department, Director General's 
> Office
> Nay Pyi Taw, Ph:095-67-405016, Fax: 095-67-405016
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-- 
Micha Silver
Arava Development Co. +972-52-3665918
http://www.surfaces.co.il


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