car (version 0.8-4)

scatterplot.matrix: Scatterplot Matrices

Description

Scatterplot matrices with univariate displays down the diagonal; spm is an abbreviation for scatterplot.matrix. This function just sets up a call to pairs.

Usage

scatterplot.matrix(x, ...)

scatterplot.matrix.formula(formula, data=NULL, subset, ...)

scatterplot.matrix.default(data, labels=colnames(data), 
diagonal=c("density", "boxplot", "histogram", "qqplot", "none"), 
adjust=1, nclass, plot.points=TRUE, smooth=TRUE, span=0.5, reg.line=lm, 
transform=FALSE, ellipse=FALSE, levels=c(.5, .9), robust=FALSE,
groups=FALSE, by.groups=FALSE, col=palette(), 
pch=1:n.groups, lwd=1, legend.plot=length(levels(groups)) > 1)

spm(x, ...)

Arguments

formula

a one-side ``model'' formula, of the form ~ x1 + x2 + ... + xk or ~ x1 + x2 + ... + xk | z where z evaluates to a factor or other variable to divide the data into groups.

data

data matrix or numeric data frame, or (for scatterplot.matrix.formula) a data frame within which to evaluate the formula.

subset

expression defining a subset of observations.

labels

variable labels (for the diagonal of the plot).

diagonal

contents of the diagonal panels of the plot.

adjust

relative bandwidth for density estimate, passed to density function.

nclass

number of bins for histogram, passed to hist function.

plot.points

if TRUE the points are plotted in each off-diagonal panel.

smooth

if TRUE a lowess smooth is plotted in each off-diagonal panel.

span

span for lowess smoother.

reg.line

if not FALSE a line is plotted using the function given by this argument; e.g., using rlm in package MASS plots a robust-regression line.

transform

if TRUE, multivariate normalizing Box-Cox transformations are computed and plotted; if a vector of powers, one for each variable, these are applied as Box-Cox power transformations prior to plotting.

ellipse

if TRUE data-concentration ellipses are plotted in the off-diagonal panels.

levels

levels or levels at which concentration ellipses are plotted; the default is c(.5, .9).

robust

if TRUE use the cov.trob function in the MASS package to calculate the center and covariance matrix for the data ellipse.

groups

a factor or other variable dividing the data into groups; groups are plotted with different colors and plotting characters.

by.groups

if TRUE, regression lines are fit by groups.

pch

plotting characters for points; default is the plotting characters in order (see par).

col

colors for points and lines; the default is the in the current color palette, starting at the second entry (see palette and par).

lwd

width for lines.

legend.plot

if TRUE then a legend for the groups is plotted in the bottom-right cell.

Value

• NULL. This function is used for its side effect: producing a plot.

See Also

pairs, scatterplot, data.ellipse, box.cox.powers, box.cox, cov.trob.

Examples

data(Duncan)
scatterplot.matrix(~income + education + prestige | type, data=Duncan)
scatterplot.matrix(~income + education + prestige, 
    transform=T, data=Duncan)