screeplotDAS {DASplusR}R Documentation

Scree Plot of PCA Results

Description

Plots the eigenvalues of the correlation or covariance matrix (i.e., the variances of the principal components), and the cumulative proportions of the explained variance against the principal component numbers.

Usage

screeplotDAS(x, col, pch, cex = rep(par("cex"), 2), 
             lty, lwd = rep(par("lwd"), 2), main = NULL, 
             sub = NULL, xlab = NULL, ylab = NULL, ...)

Arguments

x An object of class "princomp".
col Either a vector of length two giving the colors for the eigenvalues and the cumulative proportions of variance (and the tickmarks of the corresponding axes), or a single color to be used for both. If it is missing and the default color is included in the palette, it will be used along with its subsequent color. Otherwise, the first two colors of the palette will be used.
pch A vector of length two giving the plot characters to label the eigenvalues and the cumulative proportions of variance. Its values can be integers specifying the symbols, or single characters. See points for possible values and their interpretation. If a single plot character is supplied, it will be used for both. If it is missing, the default plot symbol and its subsequent symbol will be used, provided the default symbol is an integer between 0 and 25. Otherwise, the symbols 1 and 2 will be used.
cex The character expansion factor to be applied to the plot characters. Supplying a vector of length two results in different sizes for the eigenvalues and the cumulative proportions of variance.
lty A vector of length two giving the line types for the eigenvalues and the cumulative proportions of variance. Either integers, or the names of the line types as character strings can be supplied. See par for details on how to specify line types. If a single line type is supplied, it will be used for both. If it is missing, the default line type and its subsequent line type will be used, unless the default line type is a custom line type specification. In the latter case, "solid" and "dashed" will be used.
lwd The line width to be used for the eigenvalues and the cumulative proportions of variance. The lines can be of different widths by supplying a vector of length two.
main, sub, xlab, ylab Plot annotation. Note that ylab must be a vector of length two since there are two y-axes in the plot.
... Additional graphical parameters.

Details

The eigenvalues of the correlation or covariance matrix are the variances of the corresponding principal components.

Side Effects

A plot is produced on the current graphics device.

Author(s)

Andreas Alfons <andreas.alfons@student.tuwien.ac.at>

References

Mardia, K.V., Kent, J.T. and Bibby, J.M. (1979) Multivariate Analysis. Academic Press.

Reimann, C., Filzmoser, P., Garrett, R.G. and Dutter, R. (2008) Statistical Data Analysis Explained. Wiley & Sons.

See Also

ScreeplotGUI, princompDAS, biplotDAS.

Examples

  ## KOLA95_Moss data
  data(KOLA95_MOSS)
  princomp.obj <- princompDAS(data = KOLA95_MOSS, 
      vars = c("Cu","Mg","Mn","Ni","Rb","Th"), 
      logVars = c("Cu","Mg","Mn","Ni","Rb","Th"), 
      cor = TRUE, robust = "covMcd")
  screeplotDAS(princomp.obj)

[Package DASplusR version 0.0-2 Index]