thull: Plotting a Tensioned Hull

In labdsv: Ordination and Multivariate Analysis for Ecology

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 class '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

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 ordination of class ‘dsvord’. This function plots the resulting tensioned hull as an image, with optional overlays of contours.

Value

Produces a plot on the current graphic device.

Author(s)

David W. Roberts [e-mail]

Examples

data(bryceveg) # returns a data.frame 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 
                        # distributtion of a species
plot(demo.thull) # portrays the image version of the tensioned hull

labdsv documentation built on April 10, 2023, 5:08 p.m.