[R] [FORGED] Re: getting 21 very different colours

[Paul Murrell]

You could also take a look at the 'Polychrome' package

Paul

On 12/09/18 03:36, Barry Rowlingson wrote:
> On Tue, Sep 11, 2018 at 11:43 AM, Duncan Murdoch <murdoch.duncan using gmail.com>
> wrote:
> 
>> On 11/09/2018 3:34 AM, Federico Calboli wrote:
>>> Hi All,
>>>
>>> I am plotting a scatterplot of 21 populations, and I am using
>> rainbow(21)[pops.col] to generate 21 colours for the plot (which works).
>> Maybe it is because I can really process few colours at a time, but the
>> differences between the colours are not as strong as I’d like.  I can
>> specify start and end for rainbow(), but if anything that looks worse if I
>> do not just stick to 0 and 1.
>>>
>>> Is there a way of getting a set of 21 colours that maximises the
>> differences between them?
>>
>> The LAB and LUV color spaces (in the colorspace package) attempt to map
>> perceptual differences to equal distances.  You could try using a grid
>> of points in one of those spaces, but not all triples are valid.
>>
>> However, 21 colours is probably too many for your purpose.  If you
>> really want to distinguish 21 groups, you're likely going to have to use
>> other characteristics as well, such as the symbol.  You could plot 21
>> different letters in 5 different colours and it might work, but it's not
>> going to be easy for viewers.
>>
>>
> The `alphabet` and `alphabet2` palettes from the `pals` package claim 26
> "distinguishable" colours:
> 
> Details:
> 
>       The ‘alphabet’ palette has 26 distinguishable colors that have
>       logical names starting with the English alphabet letters A, B, ...
>       Z. This palette is based on the work by Green-Armytage (2010), but
>       uses the names 'orange' instead of 'orpiment', and 'magenta'
>       instead of 'mallow'.
> 
> There are some other palettes in that help page (?alphabet) that might also
> work. But 21 colours is pushing it.
> 
> Barry
> 
> 
> 
> 
> 
> 
>> Duncan Murdoch
>>
>>>
>>> I could pick them by hand, but that is about 15 colours more than I know
>> (I have a detailed colourchart, but the visual differences between
>> ’skyblue’ and ’slategrey’ elude me when plotted as dots on a plot).
>>>
>>> Cheers
>>>
>>> F
>>> --
>>> Federico Calboli
>>> LBEG - Laboratory of Biodiversity and Evolutionary Genomics
>>> Charles Deberiotstraat 32 box 2439
>>> 3000 Leuven
>>> +32 16 32 87 67
>>>
>>>
>>>
>>>
>>>
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>>
>> ______________________________________________
>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>>
> 
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> 
> ______________________________________________
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-- 
Dr Paul Murrell
Department of Statistics
The University of Auckland
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Auckland
New Zealand
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paul using stat.auckland.ac.nz
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