[GRASS-dev] Modified i.rgb.his

[Moritz Lennert]

On 27/08/16 15:54, Nikos Alexandris wrote:
 > Attached here-in a slightly updated diff (from the last diff attached in
 > #774) for i.rgb.his.
 >
 > I need time to learn/understand things (in C). Yet, I tested the "new"
 > version and it works for me.
 >
 > I would like to push this version into SVN myself. Thus, I'd like to ask
 > (in the grass-psc list) for commit access. However, I can just submit
 > another, updated, diff, in ticket #774 for someone to take over.

Please do that. Core svn access takes time, and in any case it is better 
to have everything documented in the trac ticket.

When I apply this patch I get some compiler warning that need to be 
fixed first.

Also, could you please document the bit_depth parameter in i.rgb.his.html ?

One thing I don't understand about the results:

Using the NC landsat images and running

i.rgb.his r=lsat7_2002_30 g=lsat7_2002_20 bl=lsat7_2002_10 h=h8 i=i8 
s=s8 bit_depth=8

and

i.rgb.his r=lsat7_2002_30 g=lsat7_2002_20 bl=lsat7_2002_10 h=h16 i=i16 
s=s16 bit_depth=16

I then get for intensity:

 > r.info -r i8
min=0.08431373
max=1

 > r.info -r i16
min=0.000328069
max=0.003891051

Is this expected, or is there an issue with scaling the 16-bit version 
between 0 and 1 ?

Moritz