R: Scatterplots with Boxplots

scatterplot {car}

R Documentation

Scatterplots with Boxplots

Description

Makes enhanced scatterplots, with boxplots in the margins, a lowess smooth, smoothed conditional spread, outlier identification, and a regression line; sp is an abbreviation for scatterplot.

Usage

scatterplot(x, ...)

## S3 method for class 'formula'
scatterplot(x, data, subset, xlab, ylab, legend.title, legend.coords,
	labels, ...)

## Default S3 method:
scatterplot(x, y, smooth=TRUE, spread=!by.groups, 
	span=.5, loess.threshold=5, reg.line=lm, 
	boxplots=if (by.groups) "" else "xy",
	xlab=deparse(substitute(x)), ylab=deparse(substitute(y)), 
	las=par("las"), lwd=1, lwd.smooth=lwd, lwd.spread=lwd, lty=1, 
	lty.smooth=lty, lty.spread=2,
	labels, id.method = "mahal", 
	id.n = if(id.method[1]=="identify") length(x) else 0, 
	id.cex = 1, id.col = palette()[1],
	log="", jitter=list(), xlim=NULL, ylim=NULL,
	cex=par("cex"), cex.axis=par("cex.axis"), cex.lab=par("cex.lab"), 
	cex.main=par("cex.main"), cex.sub=par("cex.sub"), 
	groups, by.groups=!missing(groups), 
	legend.title=deparse(substitute(groups)), legend.coords,
	ellipse=FALSE, levels=c(.5, .95), robust=TRUE,
	col=if (n.groups == 1) palette()[3:1] else rep(palette(), 
		length=n.groups),
	pch=1:n.groups, 
	legend.plot=!missing(groups), reset.par=TRUE, grid=TRUE, ...)
  
sp(...)

Arguments

`x`	vector of horizontal coordinates, or a “model” formula, of the form `y ~ x` or (to plot by groups) `y ~ x \| z`, where `z` evaluates to a factor or other variable dividing the data into groups. If `x` is a factor, then parallel boxplots are produced using the `Boxplot` function.
`y`	vector of vertical coordinates.
`data`	data frame within which to evaluate the formula.
`subset`	expression defining a subset of observations.
`smooth`	if `TRUE` (the default) a loess nonparametric regression line is drawn on the plot.
`spread`	if `TRUE` (the default when there are no groups), a smoother is applied to the root-mean-square positive and negative residuals from the loess line to display conditional spread and asymmetry.
`span`	span for the loess smoother.
`loess.threshold`	suppress the loess smoother if there are fewer than `loess.threshold` unique values (default, 5) of `y`.
`reg.line`	function to draw a regression line on the plot or `FALSE` not to plot a regression line.
`boxplots`	if `"x"` a boxplot for `x` is drawn below the plot; if `"y"` a boxplot for `y` is drawn to the left of the plot; if `"xy"` both boxplots are drawn; set to `""` or `FALSE` to suppress both boxplots.
`xlab`	label for horizontal axis.
`ylab`	label for vertical axis.
`las`	if `0`, ticks labels are drawn parallel to the axis; set to `1` for horizontal labels (see `par`).
`lwd`	width of linear-regression lines (default `1`).
`lwd.smooth`	width for smooth regression lines (default is the same as `lwd`).
`lwd.spread`	width for lines showing spread (default is the same as `lwd`).
`lty`	type of linear-regression lines (default `1`, solid line).
`lty.smooth`	type of smooth regression lines (default is the same as `lty`).
`lty.spread`	width for lines showing spread (default is `2`, broken line).
`id.method,id.n,id.cex,id.col`	Arguments for the labelling of points. The default is `id.n=0` for labeling no points. See `showLabels` for details of these arguments. If the plot uses different colors for groups, then the `id.col` argument is ignored and label colors are determined by the `col` argument.
`labels`	a vector of point labels; if absent, the function tries to determine reasonable labels, and, failing that, will use observation numbers.
`log`	same as the `log` argument to `plot`, to produce log axes.
`jitter`	a list with elements `x` or `y` or both, specifying jitter factors for the horizontal and vertical coordinates of the points in the scatterplot. The `jitter` function is used to randomly perturb the points; specifying a factor of `1` produces the default jitter. Fitted lines are unaffected by the jitter.
`xlim`	the x limits (min, max) of the plot; if `NULL`, determined from the data.
`ylim`	the y limits (min, max) of the plot; if `NULL`, determined from the data.
`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.
`legend.title`	title for legend box; defaults to the name of the groups variable.
`legend.coords`	coordinates for placing legend; an be a list with components x and y to specify the coordinates of the upper-left-hand corner of the legend; or a quoted keyword, such as `"topleft"`, recognized by `legend`.
`ellipse`	if `TRUE` data-concentration ellipses are plotted.
`levels`	level or levels at which concentration ellipses are plotted; the default is `c(.5, .95)`.
`robust`	if `TRUE` (the default) use the `cov.trob` function in the `MASS` package to calculate the center and covariance matrix for the data ellipses.
`col`	colors for lines and points; the default is taken from the color palette, with `palette()[3]` for linear regression lines, `palette()[2]` for nonparametric regression lines, and `palette()[1]` for points if there are no groups, and successive colors for the groups if there are groups.
`pch`	plotting characters for points; default is the plotting characters in order (see `par`).
`cex, cex.axis, cex.lab, cex.main, cex.sub`	set sizes of various graphical elements; (see `par`).
`legend.plot`	if `TRUE` then a legend for the groups is plotted in the upper margin.
`reset.par`	if `TRUE` then plotting parameters are reset to their previous values when `scatterplot` exits; if `FALSE` then the `mar` and `mfcol` parameters are altered for the current plotting device. Set to `FALSE` if you want to add graphical elements (such as lines) to the plot.
`...`	other arguments passed down and to `plot`.
`grid`	If TRUE, the default, a light-gray background grid is put on the graph

Value

If points are identified, their labels are returned; otherwise NULL is returned invisibly.

Author(s)

John Fox jfox@mcmaster.ca

Examples

scatterplot(prestige ~ income, data=Prestige, ellipse=TRUE)

scatterplot(prestige ~ income|type, data=Prestige, span=1)

scatterplot(prestige ~ income|type, data=Prestige, span=1, 
	legend.coords="topleft")

scatterplot(vocabulary ~ education, jitter=list(x=1, y=1), 
	data=Vocab, id.n=0, smooth=FALSE)

scatterplot(infant.mortality ~ gdp, log="xy", data=UN, id.n=5)

scatterplot(income ~ type, data=Prestige)

	## Not run: 
scatterplot(infant.mortality ~ gdp, id.method="identify", data=UN)
	
## End(Not run)

[Package car version 2.0-12 Index]