[GRASSLIST:4098] Re: Sharpening Lansat images

[Markus Neteler]

On Tue, Aug 03, 2004 at 01:29:00PM -0700, Ian MacMillan wrote:
> The method that I have used with the most success is i.rgb.his, then  
> i.his.rgb.  The colors sometimes get a little screwy, but usually  
> playing with the resultant bands using d.histogram and r.rescale can  
> give you something useful.  An order of operations that I have used is  
> below to produce a fairly decent "true" color image with landsat.

Another option is the Brovey transform, recently implemented
in GRASS 5.7:

i.fusion.brovey

I have written a bit for the upcoming Bangkok conference:
http://gisws.media.osaka-cu.ac.jp/grass04/viewabstract.php?id=37
-> PDF

See example Brovey transform results here (LANDSAT-7 and SRTM):
http://mpa.itc.it/rs/landsat7/index.html

Hope this helps,

 Markus