[GRASS-user] troubles with i.landsat.rgb and d.rgb

Hamish hamish_b at yahoo.com
Fri Feb 13 02:06:33 EST 2009

Renae Mackas wrote:
> I have used r.ing.dal to import different Landsat TIFF images, and am now
> trying to superimpose red, green, and blue spectral bandsto get  "real
> colour" images.
> I am under the impression that I need to use i.landsat.rgb to
> auto-balance the colours of the LANDSAT images I am using.

you do not "need" to use i.landsat.rgb, it just helps brighten things up
if the image comes out rather dark. example:

> I am using a PC,

does that mean you are running MS Windows?  native or cygwin version?
(sorry to be overly pedantic, but consider that many run linux on a PC,
and that historically many/most? GRASS users use some flavour of Linux)

> and when I run the command:
> i.landsat.rgb red=020.020.2000.055_B30
>    green=020.020.2000.055_B20
>    blue=020.020.2000.055_B10
> a microsoft windows window pops up that informs me " r.univar.exe has
> stopped working- a problem caused the program to stop working correctly. 
> Windows will close the program and notify you if a solution is vailable". 
> As long as I continue to run the i.landsat.rgb command,
> this window continues to pop up.

can you run "r.univar 020.020.2000.055_B10" from the command prompt?

> Have I made a mistake somewhere??

don't really know. might be an install problem.

can you view the scene ok in QGIS? (www.qgis.org)

> Also, once (if?) I do get i.landsat.rgb to work, will the map display
> window automatically show me the superimposed images??

no. if you are currently viewing the layers you have to do a "hard"
redraw as the GUI isn't aware that the colors have changed behind its
back and the existing view may be partially cached.

> Also, I have tried just running d.rgb on the same images:
> d.rgb red=020.020.2000.103_B30 blue=020.020.2000.103_B20
> green=020.020.2000.103_B10

if this is the native build d.rgb shouldn't work from the command prompt,
as there are no xmon to draw to (d.mon + UNIX's X-Windows). Instead use
the 'Add RGB or HIS layer' button from the GIS manager.
the cygwin version uses X-Windows (aka X11) and so allows xmons.

good luck,


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