[R] Drawing a colour wheel - bug in hcl?

hadley wickham h.wickham at gmail.com
Mon Jul 7 23:54:35 CEST 2008

> If you replace this by
>  hcl$colour <- hcl(hcl$h, hcl$c, hcl$l, fixup = FALSE)
>> with(hcl, plot(x, y, col=colour, pch=20))
> Then, the resulting "wheel" has three overlapping "holes" corresponding to
> the colors previously fixed.

Oops, thanks for pointing that out.

> Also, as hue/chroma correspond to polar coordinates in the UV plane of
> CIELUV, it makes more sense to plot wheels in the hue/chroma plane for fixed
> luminance. To draw a hue/luminance plane for fixed chroma is harder to
> interpret geometrically.

Oooh, I guess if I'd thought about that for a couple of seconds I
would have a realised that!  What are good values to use for luminance
and chroma in that case?  I can't seem to find a slice which gives me
a decently wheel-like slice?  Or should I just use fixup = TRUE, or
accept that true colour wheels displayed on rgb monitors don't look
like wheels?



More information about the R-help mailing list