# biplot

##### Biplot of Multivariate Data

Plot a biplot on the current graphics device.

- Keywords
- multivariate, hplot

##### Usage

```
biplot(x, ...)
"biplot"(x, y, var.axes = TRUE, col, cex = rep(par("cex"), 2), xlabs = NULL, ylabs = NULL, expand = 1, xlim = NULL, ylim = NULL, arrow.len = 0.1, main = NULL, sub = NULL, xlab = NULL, ylab = NULL, ...)
```

##### Arguments

- x
- The
`biplot`

, a fitted object. For`biplot.default`

, the first set of points (a two-column matrix), usually associated with observations. - y
- The second set of points (a two-column matrix), usually associated with variables.
- var.axes
- If
`TRUE`

the second set of points have arrows representing them as (unscaled) axes. - col
- A vector of length 2 giving the colours for the first and
second set of points respectively (and the corresponding axes). If a
single colour is specified it will be used for both sets. If
missing the default colour is looked for in the
`palette`

: if there it and the next colour as used, otherwise the first two colours of the palette are used. - cex
- The character expansion factor used for labelling the points. The labels can be of different sizes for the two sets by supplying a vector of length two.
- xlabs
- A vector of character strings to label the first set of
points: the default is to use the row dimname of
`x`

, or`1:n`

if the dimname is`NULL`

. - ylabs
- A vector of character strings to label the second set of
points: the default is to use the row dimname of
`y`

, or`1:n`

if the dimname is`NULL`

. - expand
- An expansion factor to apply when plotting the second set of points relative to the first. This can be used to tweak the scaling of the two sets to a physically comparable scale.
- arrow.len
- The length of the arrow heads on the axes plotted in
`var.axes`

is true. The arrow head can be suppressed by`arrow.len = 0`

. - xlim, ylim
- Limits for the x and y axes in the units of the first set of variables.
- main, sub, xlab, ylab, ...
- graphical parameters.

##### Details

A biplot is plot which aims to represent both the observations and
variables of a matrix of multivariate data on the same plot. There are
many variations on biplots (see the references) and perhaps the most
widely used one is implemented by `biplot.princomp`

.
The function `biplot.default`

merely provides the
underlying code to plot two sets of variables on the same figure.

Graphical parameters can also be given to `biplot`

: the size of
`xlabs`

and `ylabs`

is controlled by `cex`

.

##### Side Effects

a plot is produced on the current graphics device.

##### References

K. R. Gabriel (1971). The biplot graphical display of matrices with
application to principal component analysis. *Biometrika*
**58**, 453--467.

J.C. Gower and D. J. Hand (1996). *Biplots*. Chapman & Hall.

##### See Also

`biplot.princomp`

, also for examples.

*Documentation reproduced from package stats, version 3.2.5, License: Part of R 3.2.5*