plgraphics (version 1.2)

plcoord: Determines Values for Plotting with Limited "Inner" Plot Range

Description

For plots with an "inner plot range" (see Details) this function converts the data values to the coordinates in the plot

Usage

plcoord(x, range = NULL, innerrange.factor = NULL,
  innerrange.ext = NULL, plext = NULL, ploptions = NULL)

Value

vector of coordinates used for plotting, that is, unchanged x

values for those within the range and transformed values for those outside.

Attributes:

attr(,"plrange")

the range to be used when plotting

attr(,"range")

the "inner" plot range, either the argument range or the values determined by default.

attr(,"nouter")

the number of modified observations

Arguments

x

data to be represented

range

vector of 2 elements giving the inner plot range. Data beyond the given interval will be non-linearly transformed to fit within the (outer) plot margins. Defaults to robrange(x, fac=fac).

innerrange.factor

factor used to determine the default of range

innerrange.ext

factor for extending the range to determine the outer plot range

plext

vector of 1 or 2 elements setting the extension factor for the plotting range

ploptions

plotting options

Author

Werner A. Stahel

Details

When plotting data that contain outliers, the non-outlying data is represented poorly. Rather than simply clipping outliers, one can split the plotting area into an inner region, where the (non-outlying) data is plotted as usual, and a plot area margin, in which outliers are represented on a highly non-linear scale that allows to display them all.

This function converts the data to the coordinates used in the graphical display, and also returns the inner and outer ranges for plotting.

See Also

robrange

Examples

  set.seed(0)
  x <- c(rnorm(20),rnorm(3,5,10))
  ( xmod <- plcoord(x) )

  plot(x,xmod)
## This shows what high level pl functions do by default
  plot(xmod)
  abline(h=attr(xmod,"innerrange"),lty=3, lwd=2)
## plgraphics
  plyx(x)