B_08_splom {lattice} | R Documentation

## Scatter Plot Matrices

### Description

Draw Conditional Scatter Plot Matrices and Parallel Coordinate Plots

### Usage

    splom(x, data, ...)
    parallelplot(x, data, ...)

    ## S3 method for class 'formula'
    splom(x,
          data,
          auto.key = FALSE,
          aspect = 1,
          between = list(x = 0.5, y = 0.5),
          panel = lattice.getOption("panel.splom"),
          prepanel,
          scales,
          strip,
          groups,
          xlab,
          xlim,
          ylab = NULL,
          ylim,
          superpanel = lattice.getOption("panel.pairs"),
          pscales = 5,
          varnames = NULL,
          drop.unused.levels,
          ...,
          lattice.options = NULL,
          default.scales,
          default.prepanel = lattice.getOption("prepanel.default.splom"),
          subset = TRUE)
    ## S3 method for class 'formula'
    parallelplot(x,
             data,
             auto.key = FALSE,
             aspect = "fill",
             between = list(x = 0.5, y = 0.5),
             panel = lattice.getOption("panel.parallel"),
             prepanel,
             scales,
             strip,
             groups,
             xlab = NULL,
             xlim,
             ylab = NULL,
             ylim,
             varnames = NULL,
             horizontal.axis = TRUE,
             drop.unused.levels,
             ...,
             lattice.options = NULL,
             default.scales,
             default.prepanel = lattice.getOption("prepanel.default.parallel"),
             subset = TRUE)

    ## S3 method for class 'data.frame'
    splom(x, data = NULL, ..., groups = NULL, subset = TRUE)
    ## S3 method for class 'matrix'
    splom(x, data = NULL, ..., groups = NULL, subset = TRUE)

    ## S3 method for class 'matrix'
    parallelplot(x, data = NULL, ..., groups = NULL, subset = TRUE)
    ## S3 method for class 'data.frame'
    parallelplot(x, data = NULL, ..., groups = NULL, subset = TRUE)

### Arguments

`x` | The object on which method dispatch is carried out. For the `"formula"` method, a formula describing the structure of the plot, which should be of the form `~ x | g1 * g2 * ...`, where `x` is a data frame or matrix. Each of `g1,g2,...` must be either factors or shingles. The conditioning variables `g1, g2, ...` may be omitted. For the `data.frame` methods, a data frame.
`data` | For the `formula` methods, an optional data frame in which variables in the formula (as well as `groups` and `subset`, if any) are to be evaluated.
`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` | For `parallelplot`, this has the usual interpretation, i.e., a 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` | A character or expression vector or giving names to be used for the variables in `x`. By default, the column names of `x`.
`horizontal.axis` | logical indicating whether the parallel axes should be laid out horizontally (`TRUE`) or vertically (`FALSE`).
`auto.key, prepanel, scales, strip, groups, xlab, xlim, ylab, ylim, drop.unused.levels, lattice.options, default.scales, subset` | See `xyplot`
`default.prepanel` | Fallback prepanel function. See `xyplot`.
`...` | Further arguments. See corresponding entry in `xyplot` for non-trivial details.

### Details

`splom` produces Scatter Plot Matrices. The role usually played by `panel` is taken over by `superpanel`, which takes a data frame subset and is responsible for plotting it. It is called with the coordinate system set up to have both x- and y-limits from `0.5` to `ncol(z) + 0.5`. The only built-in option currently available is `panel.pairs`, which calls a further panel function for each pair `(i, j)` of variables in `z` inside a rectangle of unit width and height centered at `c(i, j)` (see `panel.pairs` for details).

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.

`parallelplot` 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.Sarkar@R-project.org

### See Also

`xyplot`, `Lattice`, `panel.pairs`, `panel.parallel`.

### 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, length.out = 4),
                    y = seq(.9, .6, length.out = 4),
                    labels = c("Three", "Varieties", "of", "Iris"),
                    cex = 2)
          })
    parallelplot(~iris[1:4] | Species, iris)
    parallelplot(~iris[1:4], iris, groups = Species,
                 horizontal.axis = FALSE, scales = list(x = list(rot = 90)))

[Package lattice version 0.20-6 Index]