Thank you very much Jari. Is the Raup--Crick dissimilarity metric the only option for a presence/absence data in "vegdist" or using binary = T could I use any other dissimilarity metric?
Best, Manuel On 27/03/2011 09:07 a.m., Jari Oksanen wrote: > On 26/03/11 17:35 PM, "Manuel Spínola"<mspinol...@gmail.com> wrote: > >> Dear list members, >> >> I got an error message working with Raup--Crick distance in metaMDS. >> >>> flora.mds = metaMDS(indicadora, distance = "raup", trace = FALSE, zerodist >> = "ignore") >> Error in isoMDS(dist, k = k, trace = isotrace) : >> zero or negative distance between objects 1 and 2 >> In addition: Warning message: >> In distfun(comm, method = distance, ...) : >> data have empty species which influence the results im method raup >> > Manuel, > > As I read it, the error message comes from isoMDS() that does not accept > zero distances, and you have decided to ignore this (by setting zerodist = > "ignore"). Either you or isoMDS must give up, and I think it is easier for > you: try setting 'zerodist = "add"', and confess that isoMDS() wins your > dispute. > > Another message you got is from vegdist() which only tells you that empty > species (= that do not occur in your data) will influence your data. That is > only informational, and not an error. > > Cheers, Jari Oksanen > > > -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río <https://sites.google.com/site/lobitoderio/> Institutional website: ICOMVIS <http://www.icomvis.una.ac.cr/> [[alternative HTML version deleted]]
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