labdsv (version 1.8-0)

plot.thull: Plotting a Tensioned Hull

Description

A tensioned hull is a minimum volume container for specified elements of an ordination. A ‘thull’ object is returned as an invisible object by plotting a thull of an NMDS or PCO (or MFSO). Subsequently plotting the returned thull results in an ‘image’ of the representation.

Usage

# S3 method for thull
plot(x,col=rainbow(20),levels=NULL,cont=TRUE,
          xlab=x$xlab,ylab=x$ylab,main=x$main,…)

Arguments

x

an object of class ‘thull’ from function thull

col

the color to use plotting the contours

levels

the specific levels desired for the contours

cont

a logical variable to control plotting contours on the image representation of the tensioned hull

xlab

the X axis label

ylab

the Y axis label

main

the main title

…

other graphics parameters

Value

Produces a plot on the current graphic device.

Details

Tensioned hull analysis fits a minimum volume envelope to specific points in an ordination. A tensioned hull object is returned from function thull of a PCO, NMDS or MFSO. This function plots the resulting tensioned hull as an image, with optional overlays of contours.

Examples

# NOT RUN {
    data(bryceveg) # returns a dataframe called bryceveg
    dis.bc <- dsvdis(bryceveg,'bray') # calculates a Bray-Curtis 
                                      # dissimilarity matrix
    nmds.bc <- nmds(dis.bc) # calculates an NMDS ordination
    plot(nmds.bc) # plots the ordination on the current device
    demo.thull <- thull(nmds.bc,bryceveg$arcpat,0.25) # calculates 
                        # the tensioned hull representing the distribution 
                        # of a species
    plot(demo.thull) # portrays the image version of the tensioned hull
# }