[R-sig-eco] vegan RDA triplot species arrows

[Tyler Smith]

Jari Oksanen <jari.oksanen at oulu.fi> writes:

>> 
>> In any case, if you are interested I would be happy to attempt to add
>> code to plot.cca to do what I'd prefer. If not, no worries, I can make a
>> wrapper function to get what I want without modifying vegan.
>> 
> Vegan has two general design principles: (1) there are design principles,
> (2) they can be overruled.
>
> I'll be happy to accept plot.cca amendment -- providing they are
> "acceptable". 

I'll see what I can do, keeping in mind the considerations you mention.

> Finally a comment about arrows as a convention in RDA: I disagree -- it is
> not a convention in RDA, but a convention in CanoDraw and its heirs. I never
> liked it when CanoDraw introduced this for the reasons I gave earlier
> (messy). Points were quite common in displaying PCA results even earlier,
> although some people used arrows, especially with small data sets.

That's interesting to know, thanks. My apologies for conflating my
textbook with universal standard practice!

Cheers,

Tyler