Plot vectors inside a unit circle (PCA loadings or correlations plots).

Plots vectors with 0 < norms < 1 inside a circle. These plots are mainly designed to represent variables in principal components space for PCAs.

Usage

vectorplot(x, ...)

# S3 method for default
vectorplot(
  x,
  y,
  col = par("col"),
  circle.col = "gray",
  ar.length = 0.1,
  pos = NULL,
  cex = par("cex"),
  labels = NULL,
  ...
)

# S3 method for loadings
vectorplot(
  x,
  choices = 1L:2L,
  col = par("col"),
  circle.col = "gray",
  ar.length = 0.1,
  pos = NULL,
  cex = par("cex"),
  labels = rownames(x),
  main = deparse(substitute(x)),
  ...
)

# S3 method for Correlation
vectorplot(
  x,
  choices = 1L:2L,
  col = par("col"),
  circle.col = "gray",
  ar.length = 0.1,
  pos = NULL,
  cex = par("cex"),
  labels = rownames(x),
  main = deparse(substitute(x)),
  ...
)

Arguments

x

An object that has a vectorplot() method, like 'loadings' or 'correlation', or a numeric vector with 0 < values < 1.

...

Further arguments passed to plot functions.

y

A numeric vector with 0 < values < 1 of same length as `x.

col

Color of the arrows and labels.

circle.col

The color for the circle around the vector plot.

ar.length

The length of the arrows.

pos

The position of text relative to arrows. If NULL, a suitable position is calculated according to the direction where the arrows are pointing.

cex

The factor of expansion for labels in the graph.

labels

The labels to draw near the arrows.

choices

A vector of two integers indicating the axes to plot.

main

The title of the plot.

Value

The object 'x' is returned invisibly. These functions are called for their side-effect of drawing a vector plot.

See also

pcomp(), loadings(), Correlation()

Examples

# Create a PCA and plot loadings and correlations
iris.pca <- pcomp(iris[, -5])
vectorplot(loadings(iris.pca))

vectorplot(Correlation(iris.pca))

# Note: on screen devices, change aspect ratio of the graph by resizing
# the window to reveal cropped labels...