[GRASS-user] Problems with i.rgb.his

[Glynn Clements]

David Finlayson wrote:

> I have an image that looks good using rgb composting:
> 
> d.rgb red=image.r green=image.g blue=image.b
> 
> Now I try to convert it to his format:
> 
> i.rgb.his red=image.r green=image.g blue=image.b hue=image.h
> int=image.i sat=image.s
> 
> but
> 
> d.his h=image.h i=image.i s=image.s
> 
> doesn't look anything like the original.
> 
> What step(s) am I forgetting?

i.rgb.his actually converts to something which could reasonably be
termed HIS/HSV/HSB, whereas d.his is a kludge; the conversion which it
performs doesn't correspond to anything which you are likely to find
in a computer graphics text.

The hsv.rgb.sh script in 5.x is probably a lot closer to what you are
looking for.

http://freegis.org/cgi-bin/viewcvs.cgi/*checkout*/grass/src/scripts/shells/hsv.rgb.sh?rev=1.2&content-type=text/plain
http://freegis.org/cgi-bin/viewcvs.cgi/*checkout*/grass/src/scripts/shells/rgb.hsv.sh?rev=1.2&content-type=text/plain

-- 
Glynn Clements <glynn at gclements.plus.com>