search for: blanquet

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 relev?. 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.ce...

...lems. Now I want to bring the releves with missing environmetal variables back to my ordination-plot. Gavin Simpson gave me the advice to use the predict-function for the same missing value problem when I was calculating a cca. This worked without problem. As my species data was recorded in Braun-Blanquet-numbers (ordinal scale) I would prefer to calculate a NMDS. Does anybody know a similar function to the predict function which works with NMDS or does anybody know how to modify the predict function so that it will work also for NMDS? Thank you very much! Kim -------- Original-Nachricht -------...

Hello I've been asked to help evaluate a vegetation data set, specifically to examine it for community similarity. The initial problem I see is that the data is ordinal. At best this only captures a relative ranking of abundance and ordinal ranks are assigned after data collection. I've been trying to find a procedure in R that can handle ordinal based classification and so far have