plot.thull {labdsv}R Documentation

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

Value

Produces a plot on the cureent grapic device.

Author(s)

David W. Roberts droberts@montana.edu

References

http://ecology.montana.msu.edu/labdsv/R

Examples

    data(bryceveg) # returns a dataframe called brycceveg
    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 rperesenting the distribution of a species
    plot(demo.thull) # portrays the image version of the tensioned hull

[Package labdsv version 1.4-1 Index]