stripchart             package: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', '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)

