R: Conditioning Plots

coplot {base}

R Documentation

Conditioning Plots

Description

This function produces two variants of the conditioning plots discussed in the reference below.

Usage

coplot(formula, data, given.values, panel = points, rows, columns,
       show.given = TRUE, col = par("fg"), pch = par("pch"),
       xlab = c(x.name, paste("Given :", a.name)),
       ylab = c(y.name, paste("Given :", b.name)),
       subscripts = FALSE,
       number = 6, overlap = 0.5, ...)
co.intervals(x, number = 6, overlap = 0.5)

Arguments

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.

x and y must be numeric, but a and b may be either numeric or factors.

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.

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.

number

integer; the number of conditioning intervals, possibly of length 2 for x and y direction.

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.

...

additional arguments to the panel function.

Details

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).

Value

co.intervals(., number, .) returns a (number \times 2) matrix, say ci, where ci[k,] is the range of x values for the k-th interval.

References

Cleveland, W. S. (1993) Visualizing Data. New Jersey: Summit Press.

Examples

## Tonga Trench Earthquakes
data(quakes)
coplot(long ~ lat | depth, data = quakes)
given.depth <- co.intervals(quakes$depth, number=4, overlap=.1)
coplot(long ~ lat | depth, data = quakes, given.v=given.depth, rows=1)

## Conditioning on 2 variables:
ll.dm <- long ~ lat | depth * mag
coplot(ll.dm, data = quakes)
coplot(ll.dm, data = quakes, number=c(4,7), show.given = c(T,F))
coplot(ll.dm, data = quakes, number=c(3,7),
       overlap=c(-.5,.1)) # negative overlap DROPS values

data(warpbreaks)
## given two factors
coplot(breaks ~ 1:54 | wool * tension, data = warpbreaks, col = 'red')

## Example with empty panels:
data(state)
attach(data.frame(state.x77))#> don't need `data' arg. below
coplot(Life.Exp ~ Income | Illiteracy * state.region, number = 3,
       panel = function(x, y, ...) panel.smooth(x, y, span = .8, ...))
detach() # data.frame(state.x77)

[Package base version 1.1 ]