[R] rcorr.cens Goodman-Kruskal gamma
Kim Vanselow
Vanselow at gmx.de
Mon Mar 9 16:13:04 CET 2009
Dear r-helpers!
I want to classify my vegetation data with hierachical cluster analysis.
My Dataset consist of Abundance-Values (Braun-Blanquet ordinal scale; ranked) for each plant species and relevé.
I found a lot of r-packages dealing with cluster analysis, but none of them is able to calculate a distance measure for ranked data.
Podani recommends the use of Goodman and Kruskals' Gamma for the distance. I found the function rcorr.cens (outx=true) of the Hmisc package which should do it.
What I don't understand is how to define the input vectors x, y with my vegetation dataset. The other thing how I can use the output of rcorr.cens for a distance measure in the cluster analysis (e.g. in vegan or amap).
Any help would be greatly appreciated,
Thank you very much,
Kim
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