R: 1-D Scatter Plots

stripchart {graphics} | R Documentation

## 1-D Scatter Plots

### Description

`stripchart` produces one dimensional scatter plots (or dot plots) of the given data. These plots are a good alternative to `boxplot`s when sample sizes are small.

### Usage

    stripchart(x, ...)

    ## S3 method for class 'formula'
    stripchart(x, data = NULL, dlab = NULL, ...,
               subset, na.action = NULL)

    ## Default S3 method:
    stripchart(x, method = "overplot", jitter = 0.1, offset = 1/3,
               vertical = FALSE, group.names, add = FALSE,
               at = NULL, xlim = NULL, ylim = NULL,
               ylab = NULL, xlab = NULL, dlab = "", glab = "",
               log = "", pch = 0, col = par("fg"), cex = par("cex"),
               axes = TRUE, frame.plot = axes, ...)

### Arguments

`x` | the data from which the plots are to be produced. In the default method the data can be specified as a single numeric vector, or as list of numeric vectors, each corresponding to a component plot. In the `formula` method, a symbolic specification of the form `y ~ g` can be given, indicating the observations in the vector `y` are to be grouped according to the levels of the factor `g`. `NA`s are allowed in the data.
`data` | a data.frame (or list) from which the variables in `x` should be taken.
`subset` | an optional vector specifying a subset of observations to be used for plotting.
`na.action` | a function which indicates what should happen when the data contain `NA`s. The default is to ignore missing values in either the response or the group.
`...` | additional parameters passed to the default method, or by it to `plot.window`, `points`, `axis` and `title` to control the appearance of the plot.
`method` | the method to be used to separate coincident points. The default method `"overplot"` causes such points to be overplotted, but it is also possible to specify `"jitter"` to jitter the points, or `"stack"` have coincident points stacked. The last method only makes sense for very granular data.
`jitter` | when `method = "jitter"` is used, `jitter` gives the amount of jittering applied.
`offset` | when stacking is used, points are stacked this many line-heights (symbol widths) apart.
`vertical` | when vertical is `TRUE` the plots are drawn vertically rather than the default horizontal.
`group.names` | group labels which will be printed alongside (or underneath) each plot.
`add` | logical, if true add the chart to the current plot.
`at` | numeric vector giving the locations where the charts should be drawn, particularly when `add = TRUE`; defaults to `1:n` where `n` is the number of boxes.
`ylab, xlab` | labels: see `title`.
`dlab, glab` | alternate way to specify axis labels: see ‘Details’.
`xlim, ylim` | plot limits: see `plot.window`.
`log` | on which axes to use a log scale: see `plot.default`
`pch, col, cex` | Graphical parameters: see `par`.
`axes, frame.plot` | Axis control: see `plot.default`.

### Details

Extensive examples of the use of this kind of plot can be found in Box, Hunter and Hunter or Seber and Wild.

The `dlab` and `glab` labels may be used instead of `xlab` and `ylab` if those are not specified. `dlab` applies to the continuous data axis (the X axis unless `vertical` is `TRUE`), `glab` to the group axis.

### Examples

    x <- stats::rnorm(50)
    xr <- round(x, 1)
    stripchart(x) ; m <- mean(par("usr")[1:2])
    text(m, 1.04, "stripchart(x, \"overplot\")")
    stripchart(xr, method = "stack", add = TRUE, at = 1.2)
    text(m, 1.35, "stripchart(round(x,1), \"stack\")")
    stripchart(xr, method = "jitter", add = TRUE, at = 0.7)
    text(m, 0.85, "stripchart(round(x,1), \"jitter\")")

    stripchart(decrease ~ treatment,
        main = "stripchart(OrchardSprays)",
        vertical = TRUE, log = "y", data = OrchardSprays)

    stripchart(decrease ~ treatment, at = c(1:8)^2,
        main = "stripchart(OrchardSprays)",
        vertical = TRUE, log = "y", data = OrchardSprays)

[Package graphics version 4.0.5 Index]