[GRASS-user] Landsat classification with CORINE CLC color codes?

[Nikos Alexandris]

On Mon, 2009-01-19 at 13:30 -0800, Hamish wrote:
> Dimos wrote:
> > > > 44 CORINE CLC RGB  color codes are mentioned for each of the 44
> > > > land use classes at:
>   http://dataservice.eea.europa.eu/download.asp?id=14234&filetype=.csv
> > > >
> > > > Can we classify a Landsat RGB image based on these rgb color
> codes
> > > > in GRASS GIS and how?
> 
> Markus: 
> > > In my opinion it doesn't make much sense to use the RGB colors
> here
> > > since they are arbitrary (well, ok, ideally "close" to natural
> colors).
> 
> I am trying to understand; there are 256^3 RGB possibilities (@ 8bits
> per
> channel) and CORINE have selected 44 of those possibilities to give
> labels
> to? Your chances of hitting those exactly are rather low. I suppose
> these
> are meant to be 3D spectral peaks somehow with the land-use category
> doing
> like a 3D form of a nearest-neighbor thiessen polygon.
> 
> 
> It seems a rather lossy and sensitive approach, ie it would be better
> to
> base it on all 7 bands & include some method to remove time of
> day/luminance
> issues. e.g. specify color normalization step first [eg
> i.landsat.rgb],
> or convert LANDSAT r,g,b pseudo-visual bands to HIS and classify on
> that
> (I'm guessing that hue would be less sensitive to sun angle).

Hmmm??

Maybe I am talking nonsense but, I think, the designers must have tried
to create a color scheme that, not only is connected in a way to natural
colors, but also that makes the land cover classes easy to discriminate
visually and the whole thing a *nice* looking map. Or maybe not... (?).

By the way, below are the official rgb combinations for use with
"\usepackage{colortbl}" (LaTeX).

Kind regards, Nikos
============================================
\definecolor{111}{rgb}{0.8984,0,0.3008}
\definecolor{112}{rgb}{0.9961,0,0}
\definecolor{121}{rgb}{0.7969,0.3008,0.9453}
\definecolor{122}{rgb}{0.7969,0,0}
\definecolor{123}{rgb}{0.8984,0.7969,0.7969}
\definecolor{124}{rgb}{0.8984,0.7969,0.8984}
\definecolor{131}{rgb}{0.6484,0,0.7969}
\definecolor{132}{rgb}{0.6484,0.3008,0}
\definecolor{133}{rgb}{0.9961,0.3008,0.9961}
\definecolor{141}{rgb}{0.9961,0.6484,0.9961}
\definecolor{142}{rgb}{0.9961,0.8984,0.9961}
\definecolor{211}{rgb}{0.9961,0.9961,0.6563}
\definecolor{212}{rgb}{0.9961,0.9961,0}
\definecolor{213}{rgb}{0.8984,0.8984,0}
\definecolor{221}{rgb}{0.8984,0.5,0}
\definecolor{222}{rgb}{0.9453,0.6484,0.3008}
\definecolor{223}{rgb}{0.8984,0.6484,0}
\definecolor{231}{rgb}{0.8984,0.8984,0.3008}
\definecolor{241}{rgb}{0.9961,0.8984,0.6484}
\definecolor{242}{rgb}{0.9961,0.8984,0.3008}
\definecolor{243}{rgb}{0.8984,0.7969,0.3008}
\definecolor{244}{rgb}{0.9453,0.7969,0.6484}
\definecolor{311}{rgb}{0.5,0.9961,0}
\definecolor{312}{rgb}{0,0.6484,0}
\definecolor{313}{rgb}{0.3008,0.9961,0}
\definecolor{321}{rgb}{0.7969,0.9453,0.3008}
\definecolor{322}{rgb}{0.6484,0.9961,0.5}
\definecolor{323}{rgb}{0.6484,0.8984,0.3008}
\definecolor{324}{rgb}{0.6484,0.9453,0}
\definecolor{331}{rgb}{0.8984,0.8984,0.8984}
\definecolor{332}{rgb}{0.7969,0.7969,0.7969}
\definecolor{333}{rgb}{0.7969,0.9961,0.7969}
\definecolor{334}{rgb}{0,0,0}
\definecolor{335}{rgb}{0.6484,0.8984,0.7969}
\definecolor{411}{rgb}{0.6484,0.6484,0.9961}
\definecolor{412}{rgb}{0.3008,0.3008,0.9961}
\definecolor{421}{rgb}{0.7969,0.7969,0.9961}
\definecolor{422}{rgb}{0.8984,0.8984,0.9961}
\definecolor{423}{rgb}{0.6484,0.6484,0.8984}
\definecolor{511}{rgb}{0,0.7969,0.9453}
\definecolor{512}{rgb}{0.5,0.9453,0.8984}
\definecolor{521}{rgb}{0,0.9961,0.6484}
\definecolor{522}{rgb}{0.6484,0.9961,0.8984}
\definecolor{523}{rgb}{0.8984,0.9453,0.9961}