[R] metaMDS using Dissimilarity matrix

From: Birgit Lemcke <birgit.lemcke_at_systbot.uzh.ch>
Date: Thu, 15 May 2008 13:13:14 +0200


Hello R-user community!

I am running R 2.7.0 on a Power Book (Tiger). (I am still R and statistics beginner)

Presently I try to run the function metaMDS (vegan) using an existing dissimilarity-matrix.

As I would like to start with this matrix I thought I could just give the matrix using the x= -argument

	Test<-metaMDS(x=Dist.Gower)
	Fehler in inherits(comm, "dist") : Argument "comm" fehlt (ohne  
Standardwert)

But obviously that is not the way it works.

The second problem is that it seems that I have zero distance value between some objects what causes a problem in isoMDS (vegan)

	Test<-isoMDS(Dist.GowerTest) Fehler in isoMDS(Dist.GowerTest)
	 : zero or negative distance between objects 240 and 241


Sorry might be that I am just to stupid to understand the documentation, but could somebody help me anyway.

Thanks in advance

B.

Birgit Lemcke
Institut für Systematische Botanik
Zollikerstrasse 107
CH-8008 Zürich
Switzerland
Ph: +41 (0)44 634 8351
birgit.lemcke_at_systbot.uzh.ch

175 Jahre UZH
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19. April 2008, 10.00 Uhr bis 02.00 Uhr
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