[R] dichromat, regexp, and grid objects

[Ken Knoblauch]

baptiste auguie <baptiste.auguie <at> googlemail.com> writes:
> Replying to myself here,
> Hadley pointed out this website on the ggplot2 mailing list,
> 
> http://colororacle.cartography.ch/
> 
> And this seems like a more straight-forward solution to my query
> (albeit not using R). It sort of makes sense to momentarily alter the
> computer display rather than parse the code for colour and fill
> regular expressions...
> 2009/9/28 baptiste auguie <baptiste.auguie <at> googlemail.com>:
> > Dear list,

> > The dichromat package defines a dichromat function which "Collapses
> > red-green color distinctions to approximate the effect of the two
> > common forms of red-green colour blindness, protanopia and
> > deuteranopia."

> > All the best,
> >
> > baptiste
Just to point out a fact or two with respect to the information on the 
indicated web page and a statement above.  While roughly 8% of males
are classified as color-deficient by standard tests, as indicated at the
site to which the link points, only about 2% are actually dichromats, 
i.e., protanopes and deuteranopes, referred to above as "common forms",
and to which the dichromat package is directly relevant.  Dichromatic
vision is reduced to 2 dimensions from the normal 3.  Most of the
other 6% (i.e., the most common forms) are what are termed 
anomalous trichromats and to whom the renditions of the dichromat
package are not actually appropriate, as the color spaces of such
observers are not a subspace of that of a normal observer.  Such
individuals really see the world a bit differently, as they may very
well call something as red that a normal observer would call green or
vice versa depending what kind of anomalous trichromat one is.
So, strictly speaking, the dichromat package is of great value in avoiding color
choices that about 1% of the population would have trouble discriminating.

Ken

-- 
Ken Knoblauch
Inserm U846
Stem-cell and Brain Research Institute
Department of Integrative Neurosciences
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