splom {lattice}R Documentation

Scatter Plot Matrices

Description

Draw Conditional Scatter Plot Matrices and Parallel Coordinate Plots

Usage

splom(formula,
      data,
      aspect = 1,
      between = list(x = 0.5, y = 0.5),
      panel = if (is.null(groups)) "panel.splom" else "panel.superpose",
      superpanel = "panel.pairs",
      pscales = 5,
      varnames, ...)
parallel(formula,
         data = list(x = 0.5, y = 0.5),
         between,
         panel = "panel.parallel",
         varnames,
         ...)

Arguments

formula a formula describing the structure of the plot, which should be of the form ~ x | g1 * g2 * ..., where x is a data frame or a matrix. Each of g1,g2,... must be either factors or shingles. The conditioning variables g1,g2,... may be omitted, in which case the leading ~ may also be omitted.
data a data frame containing values for any variables in the formula. By default the environment where the function was called from is used.
aspect aspect ratio of each panel (and subpanel), square by default for splom.
between to avoid confusion between panels and subpanels, the default is to show the panels of a splom plot with space between them.
panel function that is used to plot the data on each subpanel of a splom display. Usual interpretation for densityplot.
superpanel function that sets up the splom display, by default as a scatterplot matrix.
pscales a numeric value or a list. If pscales is a single number, it tells the approximate number of equally-spaced ticks that should appear on each axis. If pscales is a list, it should have p components, each of which is itself a list with two components: a numeric vector at and a character vector labels. These two vectors tell where labelled tick marks are placed on the axes, which are drawn inside the diagonal cells. Factor variables are labelled with the factor names. Use pscales=0 to supress the axes entirely.
varnames character vector giving the names of the p variables in x. By default, the column names of x.
... other arguments

Details

splom produces Scatter Plot Matrices. The role usually played by panel is taken over by superpanel, which determines how the columns of x are to be arranged for pairwise plots. The only available option currently is panel.pairs. (Writing new superpanel functions would need knowledge of grid.)

The scales argument does not have its usual interpretation in splom. Its function is partly served by pscales. However, components of scale which are sensible would be supported (in future if not already supported). The rot component should be specified as a vector of length 2 for the labels of the horizontal and vertical labels respectively.

parallel draws Parallel Coordinate Plots. (Difficult to describe, see example.)

These and all other high level Trellis functions have several arguments in common. These are extensively documented only in the help page for xyplot, which should be consulted to learn more detailed usage.

Value

An object of class ``trellis''. The `update' method can be used to update components of the object and the `print' method (usually called by default) will plot it on an appropriate plotting device.

Author(s)

Deepayan Sarkar deepayan@stat.wisc.edu

See Also

xyplot, Lattice

Examples

data(iris)
super.sym <- trellis.par.get("superpose.symbol")
splom(~iris[1:4], groups = Species, data = iris,
      panel = panel.superpose,
      key = list(title = "Three Varieties of Iris",
                 columns = 3, 
                 points = list(pch = super.sym$pch[1:3],
                 col = super.sym$col[1:3]),
                 text = list(c("Setosa", "Versicolor", "Virginica"))))
splom(~iris[1:3]|Species, data = iris, 
      layout=c(2,2), pscales = 0,
      varnames = c("Sepal\nLength", "Sepal\nWidth", "Petal\nLength"),
      page = function(...) {
          grid.text(x = seq(.6, .8, len = 4), 
                    y = seq(.9, .6, len = 4), 
                    label = c("Three", "Varieties", "of", "Iris"),
                    gp = gpar(fontsize=20))
      })

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