plot.CAvariants {CAvariants}

Main plot function

Description

This function produces the graphical display for the selected variant of correspondence analysis. When catype = "CA" catype = "NSCA" and plottype = "classic", the function produces a plot of the principal coordinates for the row and column categories.
When plottype = "biplot", it produces a biplot graphical display, or a polynomial biplot in case of ordered variables. For an ordered analysis only the polynomial biplots are constructed. In particular, for the singly ordered variants only the row isometric polynomial biplot is appropriate. When the parameter catype defines an ordered variant of CA, the input parameter plottype should be equal to plottype = "biplot". If biptype = "row", it will produce a row isometric polynomial biplot.

Usage

## S3 method for class 'CAvariants'
plot(x, firstaxis = 1, lastaxis = 2, thirdaxis = 3, cex = 0.8, 
cex.lab = 0.8, plottype = "biplot", biptype = "row",  
scaleplot = 1, posleg = "right", pos = 2, ell = FALSE,  
alpha = 0.05, plot3d = FALSE, size1 = 1.5, size2 = 3, ...)

Arguments

x

The name of the output object used with the main function CAvariants.

firstaxis

The horizontal polynomial, or principal, axis. By default, firstaxis = 1.

lastaxis

The vertical polynomial, or principal, axis. By default, lastaxis = 2.

thirdaxis

The third polynomial, or principal, axis in tridimensional plot. By default, thirdaxis = 3.

cex

The parameter for setting the size of the character labels for the points in a graphical display. By default, cex = 0.8.

cex.lab

The parameter for setting the size of the character labels of axes in graphical displays. By default, cex.lab = 0.8.

plottype

The type of graphical display required (either a correspondence plot or a biplot). The type of graphical display to be constructed. By default, plottype = "biplot"; the alternative is plottype = "classic".

biptype

The parameter for specifying the type of biplot. One may specify a row-isometric biplot (biptype = "row") or a column-isometric biplot (biptype = "column"). This feature is available for the nominal symmetrical and non-symmetrical correspondence analyses. By default, a row-isometric biplot, biptype = "row", is produced.

scaleplot

The parameter for scaling the classic plot and biplot coordinates. See Gower et al. (2011), section 2.3.1, or page 135 of Beh and Lombardo (2014). By default, scaleplot = 1.

posleg

The position of the legend when portraying trends of the categories for ordered variants of correspondence analysis. By default, posleg = "right".

pos

The parameter that specifies the position of label of each point in the graphical display. By default, pos = 2.

ell

The logical parameter which specifies whether algebraic confidence ellipses are to be included in the plot or not. Setting the input parameter to ell = TRUE will assess the statistical significance of each category to the association between the variables. By default, ell = FALSE.

alpha

The confidence level of the elliptical regions. By default, alpha = 0.05.

plot3d

The logical parameter specifies whether a 3D plot is to be included in the output or not. By default, plot3d = FALSE.

size1

The size of the plotted symbol. By default, size = 1.5.

size2

The size of the plotted text. By default, size = 3.

...

Further arguments passed to, or from, other functions.

Details

It produces either a classical or biplot graphical display. Further, when catype = "DOCA", catype = "SOCA", catype = "DONSCA" or catype = "SONSCA", the trends of the row and column variables (after the reconstruction of column profiles by the polynomials) is portrayed.
For classical biplot displays, it superimposes the algebraic confidence ellipses. It uses the secondary plot function caellipse (or nscaellipse) for the symmetrical (or non symmetrical) CA variants.

Note

For the classical plots, row and column principal coordinates are plotted. For biplots, one set of coordinates is the standard coordinates and the other is the principal coordinates. When an ordered variant of correspondence analysis is performed, the biplot is constructed where one set of coordinates consists of the standard polynomial coordinates and the other one is the principal polynomial coordinates.

Author(s)

Rosaria Lombardo and Eric J Beh

References

Beh EJ and Lombardo R 2014 Correspondence Analysis: Theory, Practice and New Strategies. Wiley.
Gower J, Lubbe S, and le Roux, N 2011 Understanding Biplots. Wiley.
Lombardo R Beh EJ 2016 Variants of Simple Correspondence Analysis. The R Journal, 8 (2), 167–184.
Lombardo R Beh EJ and Kroonenberg PM 2016 Modelling Trends in Ordered Correspondence Analysis Using Orthogonal Polynomials. Psychometrika, 81(2), 325–349.

Examples

data(asbestos)
resasbestosCA<-CAvariants(asbestos, catype = "CA", M=2) 
plot(resasbestosCA, plottype = "classic", plot3d = TRUE)
plot(resasbestosCA, plottype = "classic",  ell = TRUE)
plot(resasbestosCA, plottype = "biplot", biptype = "column", scaleplot=1.5)
resasbestosDOCA<-CAvariants(asbestos, catype = "DOCA") 
plot(resasbestosDOCA, plottype = "biplot", biptype = "column")
resasbestosNSCA<-CAvariants(asbestos, catype = "NSCA") 
plot(resasbestosNSCA, plottype = "biplot", biptype = "column", plot3d = TRUE)