Hello everyone,
I'm working with R 2.4.1 on a PC running with XP.
Trying to run isoMDS as follows:
Gquad.mat <- Gquads[4:10] # extracts only the metric data variables
Gquad.dist <- dist(Gquad.mat)
Gquad.mds <- isoMDS(Gquad.dist)
plot(Gquad.mds$points, type = "n")
text(Gquad.mds$points, labels = as.character(Gquads$Quadname), cex = .5)
The data.frame includes 711 records, and the first 3 columns contain
categorical variables which I exclude from the analysis.
When I invoke the script above an error message is returned.
Error in isoMDS(Gquad.dist) : zero or negative distance between objects
179 and 180.
How can I handle this, is it valid to add 0.5 to every element in the
distance matrix or is someother alternative more appropriate?
Thanks in advance
Steve
Steve Friedman, PhD
Everglades Division
Senior Environmental Scientist, Landscape Ecology
South Florida Water Management District
3301 Gun Club Road
West Palm Beach, Florida 33406
email: [EMAIL PROTECTED]
Office: 561 - 682 - 6312
Fax: 561 - 682 - 5980
If you are not doing what you truly enjoy its your obligation to
yourself to change.
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