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,
             between = list(x = 0.5, y = 0.5),
             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`

Usual interpretation for `parallel`, namely the function that creates the display within each panel.
For `splom`, the terminology is slightly complicated. The role played by the panel function in most other high-level functions is played here by the `superpanel` function, which is responsible for the display for each conditional data subset. `panel` is simply an argument to the default `superpanel` function `panel.pairs`, and is passed on to it unchanged. It is used there to create each pairwise display. See `panel.pairs` for more useful options.

`superpanel` | function that sets up the splom display, by default as a scatterplot matrix.
`pscales` | a numeric value or a list, meant to be a less functional substitute for the `scales` argument in `xyplot` etc. This argument is passed to the `superpanel` function, and is handled by the default superpanel function `panel.pairs`. The help page for the latter documents this argument in more detail.
`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`.

Many of the finer customizations usually done via arguments to high level function like `xyplot` are instead done by `panel.pairs` for `splom`. These include control of axis limits, tick locations and prepanel calcultions. If you are trying to fine-tune your `splom` plot, definitely look at the `panel.pairs` help page. The `scales` argument is usually not very useful in `splom`, and trying to change it may have undesired effects.

`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`, `panel.pairs`

### Examples

    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(...) {
              ltext(x = seq(.6, .8, len = 4),
                    y = seq(.9, .6, len = 4),
                    lab = c("Three", "Varieties", "of", "Iris"),
                    cex = 2)
          })
    parallel(~iris[1:4] | Species, iris)

[Package lattice version 0.10-14 Index]