vf {ecodist} | R Documentation |
Fits environmental variables to an ordination configuration.
vf(ord, vars, nperm = 100)
ord |
matrix containing a 2-dimensional ordination result with axes as columns. |
vars |
matrix with ancillary variables as columns. |
nperm |
number of permutation for the significance test. If nperm = 0, the test will be omitted. |
Vector fitting finds the maximum correlation of the individual variables with a configuration of samples in ordination space.
an object of class vf containing matrix with the first 2 columns containing the scores for every variable in each of the 2 dimensions of the ordination space. r is the maximum correlation of the variable with the ordination space, and pval is the result of the permutation test.
Sarah Goslee, Sarah.Goslee@ars.usda.gov
Jongman, R.H.G., C.J.F. ter Braak and O.F.R. van Tongeren. 1995. Data analysis in community and landscape ecology. Cambridge University Press, New York.
## Not run: # Example of multivariate analysis using built-in iris dataset data(iris) iris <- iris[seq(1, 150, by=3),] iris.md <- distance(iris[,1:4], "mahal") # Minimum-stress 2-dimensional nonmetric multidimensional scaling configuration # Uses small number of separate ordinations (5) to increase speed of example. # Use more for final analysis. iris.nmds <- nmds(iris.md, mindim=2, maxdim=2, nits=3) iris.nmin <- nmds.min(iris.nmds) # Plot NMDS result with symbols denoting species plot(iris.nmin, pch=as.numeric(iris[,5])) # Fit vectors for the main variables to the NMDS configuration iris.vf <- vf(iris.nmin, iris[,1:4], nperm=10) plot(iris.vf, col="blue") ## End(Not run)