coplot {graphics}  R Documentation 
This function produces two variants of the conditioning plots discussed in the reference below.
coplot(formula, data, given.values, panel = points, rows, columns, show.given = TRUE, col = par("fg"), pch = par("pch"), bar.bg = c(num = gray(0.8), fac = gray(0.95)), xlab = c(x.name, paste("Given :", a.name)), ylab = c(y.name, paste("Given :", b.name)), subscripts = FALSE, axlabels = function(f) abbreviate(levels(f)), number = 6, overlap = 0.5, xlim, ylim, ...) co.intervals(x, number = 6, overlap = 0.5)
formula 
a formula describing the form of conditioning plot. A
formula of the form y ~ x  a indicates that plots of
y versus x should be produced conditional on the
variable a . A formula of the form y ~ x a * b
indicates that plots of y versus x should be produced
conditional on the two variables a and b .
All three or four variables may be either numeric or factors. When x or y are factors, the result is almost as if
as.numeric() was applied, whereas for factor
a or b , the conditioning (and its graphics if
show.given is true) are adapted.

data 
a data frame containing values for any variables in the
formula. By default the environment where coplot was called
from is used. 
given.values 
a value or list of two values which determine how
the conditioning on a and b is to take place.
When there is no b (i.e., conditioning only on a ),
usually this is a matrix with two columns each row of which gives an
interval, to be conditioned on, but is can also be a single vector
of numbers or a set of factor levels (if the variable being
conditioned on is a factor). In this case (no b ),
the result of co.intervals can be used directly as
given.values argument.

panel 
a function(x, y, col, pch, ...)
which gives the action to be carried out in
each panel of the display. The default is points . 
rows 
the panels of the plot are laid out in a rows by
columns array. rows gives the number of rows in the
array. 
columns 
the number of columns in the panel layout array. 
show.given 
logical (possibly of length 2 for 2 conditioning
variables): should conditioning plots be shown for the
corresponding conditioning variables (default TRUE ) 
col 
a vector of colors to be used to plot the points. If too short, the values are recycled. 
pch 
a vector of plotting symbols or characters. If too short, the values are recycled. 
bar.bg 
a named vector with components "num" and
"fac" giving the background colors for the (shingle) bars,
for numeric and factor conditioning variables respectively. 
xlab 
character; labels to use for the x axis and the first conditioning variable. If only one label is given, it is used for the x axis and the default label is used for the conditioning variable. 
ylab 
character; labels to use for the y axis and any second conditioning variable. 
subscripts 
logical: if true the panel function is given an
additional (third) argument subscripts giving the subscripts
of the data passed to that panel. 
axlabels 
function for creating axis (tick) labels when x or y are factors. 
number 
integer; the number of conditioning intervals,
for a and b, possibly of length 2. It is only used if the
corresponding conditioning variable is not a factor . 
overlap 
numeric < 1; the fraction of overlap of the conditioning variables, possibly of length 2 for x and y direction. When overlap < 0, there will be gaps between the data slices. 
xlim 
the range for the x axis. 
ylim 
the range for the y axis. 
... 
additional arguments to the panel function. 
x 
a numeric vector. 
In the case of a single conditioning variable a
, when both
rows
and columns
are unspecified, a “close to
square” layout is chosen with columns >= rows
.
In the case of multiple rows
, the order of the panel
plots is from the bottom and from the left (corresponding to
increasing a
, typically).
A panel function should not attempt to start a new plot, but just plot
within a given coordinate system: thus plot
and boxplot
are not panel functions.
The rendering of arguments xlab
and
ylab
is not controlled by par
arguments
cex.lab
and font.lab
even though they are plotted by
mtext
rather than title
.
co.intervals(., number, .)
returns a (number
x
2) matrix
, say ci
, where ci[k,]
is
the range
of x
values for the k
th interval.
Chambers, J. M. (1992) Data for models. Chapter 3 of Statistical Models in S eds J. M. Chambers and T. J. Hastie, Wadsworth & Brooks/Cole.
Cleveland, W. S. (1993) Visualizing Data. New Jersey: Summit Press.
## Tonga Trench Earthquakes coplot(lat ~ long  depth, data = quakes) given.depth < co.intervals(quakes$depth, number=4, overlap=.1) coplot(lat ~ long  depth, data = quakes, given.v=given.depth, rows=1) ## Conditioning on 2 variables: ll.dm < lat ~ long  depth * mag coplot(ll.dm, data = quakes) coplot(ll.dm, data = quakes, number=c(4,7), show.given=c(TRUE,FALSE)) coplot(ll.dm, data = quakes, number=c(3,7), overlap=c(.5,.1)) # negative overlap DROPS values ## given two factors Index < seq(length=nrow(warpbreaks)) # to get nicer default labels coplot(breaks ~ Index  wool * tension, data = warpbreaks, show.given = 0:1) coplot(breaks ~ Index  wool * tension, data = warpbreaks, col = "red", bg = "pink", pch = 21, bar.bg = c(fac = "light blue")) ## Example with empty panels: with(data.frame(state.x77), { coplot(Life.Exp ~ Income  Illiteracy * state.region, number = 3, panel = function(x, y, ...) panel.smooth(x, y, span = .8, ...)) ## y ~ factor  not really sensical, but 'show off': coplot(Life.Exp ~ state.region  Income * state.division, panel = panel.smooth) })