orank {dave} R Documentation

## Ranking by orthogonal components (RANK)

### Description

Given a correlation matrix of rows or columns this selects the variable sharing a maximum variance with all others and declares this rank 1. Reduces the matrix (covariances, correlations) by the contribution of the variable ranked first. Repeats the process to derive consecutive ranks until no variance is left.

### Usage

orank(veg, use, rlimit=5, y=1, x.axis=NULL, y.axis=NULL,...)
orank1(veg, use, rlimit=5, y=1, x.axis=NULL, y.axis=NULL)

## Default S3 method:
orank(veg, use, rlimit=5, y=1, x.axis=NULL, y.axis=NULL,...)
## S3 method for class 'orank'
plot(x,...)
## S3 method for class 'orank'
summary(object,...)


### Arguments

 veg This is a vegetation data frame, releves are rows, species columns use Either "rows" or "columns" rlimit The maximum number of ranks to be determined y Transformation of species scores: x'= x exp(y) x.axis Horizontal axis used for plotting result in a sampling plan y.axis Vertical axis used for plotting result in a sampling plan x An object of class "orank" ... Further variables used for printing object An object of class "orank"

### Details

If x-axis=NULL or y-axis=NULL then a pcoa-ordination is computed and the first two axes used for plotting

### Value

An object of class "orank" with at least the following items:

 use Either "rows" or "columns" n.ranks The number of ranks var.names Names of the ranked variables var.explained Explained variance of the ranked variables var.percent Percentage of the variance explained cum.var Cummulative variance of ranked variables, percentage x.axis The same as input parameter x.axis y.axis The same as input parameter y.axis

### Note

The present function exclusively relies on a correlation matrix, function cor.

Otto Wildi

### References

Orloci, L. 1973. Ranking characters by a dispersion criterion. Nature 244: 371–373.

Wildi, O. 2017. Data Analysis in Vegetation Ecology. 3rd ed. CABI, Oxfordshire, Boston.

### Examples

# Uses vegetation data frame sveg with vegetation data
# and ssit with corresponding x- and y-axes scores
x.axis=ssit$x.axis ; y.axis=ssit$y.axis
o.orank<- orank(sveg,use="rows",rlimit=5,y=0.25,x.axis,y.axis)
plot(o.orank)


[Package dave version 2.0 Index]