Dear Sarah,
that sounds good to me, thanks!
Still, I have two more questions:
The variable fitting with vf() does only work when I "dummy-transform"
my categorical variables. Are the derived correlations then still
comparable to the Gower distance - PCoA scores where my categorical
variables where defined as such?
Is it reasonable to do more than the correlations with two axes with
vf(), i.e. after calculating the correlation for the first and the
second axis doing the same for the third and the forth? I guess this is
a very naive question, but shouldn't this work for the p-Values since
they are calculated with a permutation procedure?
Best
Jan
Sarah Goslee wrote:
It isn't "just like a PCA" but you can use a permutation procedure to fit
the traits to a 2-dimensional ordination configuration using vf() in the
ecodist package.
Sarah
On Mon, Oct 19, 2009 at 7:44 AM, Jan Hanspach <jan.hansp...@ufz.de> wrote:
Dear all,
I have a bunch of plant species and their traits (life span, pollination
type, strategy type, association to human disturbance... overall 5
categorical and two interval scaled variables). I want to know how the
traits are interrelated, e.g. are annual plants predominantly ruderals
that grow in habitats strongly disturbed by humans.
Therefore I calculated a Gower dissimilarity matrix on the species
traits (species=rows, traits=columns; using daisy(), which seems to be
appropriate for mixed variable types). With the dissimilartiy matrix I
calculate a PCoA using cmdscale and that works fine (beside some
negative Eigenvalues).
Now, I want to know if it is possible to get rotations for my traits,
like it is calculated for a PCA? So that I can plot my traits within the
ordinations space (or give the values in a table).
Thanks!
Jan
--
Jan Hanspach
Doktorand / Department Biozönoseforschung
PhD-Student / Department of Community Ecology
Helmholtz-Zentrum für Umweltforschung GmbH - UFZ
Helmholtz Centre for Environmental Research - UFZ
Theodor-Lieser-Str. 4 / 06120 Halle (Saale) / Germany
jan.hansp...@ufz.de / http://www.ufz.de
phone +49 345 558 5307 / Fax +49 345 558 5329
Home: http://www.ufz.de/index.php?en=10434
Protected areas in Germany under climate change:
http://www.pik-potsdam.de/vme/schutzgebiete
http://www.pik-potsdam.de/infothek/klimawandel-und-schutzgebiete
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