Skye

0th

Percentile

AFM Compositions of Aphyric Skye Lavas

The Skye data frame has 23 rows and 3 columns.

Keywords
datasets
Usage
Skye
Format

This data frame contains the following columns:

A

Percentage of sodium and potassium oxides.

F

Percentage of iron oxide.

M

Percentage of magnesium oxide.

References

J. Aitchison (1986) The Statistical Analysis of Compositional Data. Chapman and Hall, p.360.

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

Aliases
  • Skye
Examples
# NOT RUN {
# ternary() is from the on-line answers.
ternary <- function(X, pch = par("pch"), lcex = 1,
                    add = FALSE, ord = 1:3, 
# }
# NOT RUN {
…
# }
# NOT RUN {
)
{
  X <- as.matrix(X)
  if(any(X < 0)) stop("X must be non-negative")
  s <- drop(X %*% rep(1, ncol(X)))
  if(any(s<=0)) stop("each row of X must have a positive sum")
  if(max(abs(s-1)) > 1e-6) {
    warning("row(s) of X will be rescaled")
    X <- X / s
  }
  X <- X[, ord]
  s3 <- sqrt(1/3)
  if(!add)
  {
    oldpty <- par("pty")
    on.exit(par(pty=oldpty))
    par(pty="s")
    plot(c(-s3, s3), c(0.5-s3, 0.5+s3), type="n", axes=FALSE,
         xlab="", ylab="")
    polygon(c(0, -s3, s3), c(1, 0, 0), density=0)
    lab <- NULL
    if(!is.null(dn <- dimnames(X))) lab <- dn[[2]]
    if(length(lab) < 3) lab <- as.character(1:3)
    eps <- 0.05 * lcex
    text(c(0, s3+eps*0.7, -s3-eps*0.7),
         c(1+eps, -0.1*eps, -0.1*eps), lab, cex=lcex)
  }
  points((X[,2] - X[,3])*s3, X[,1], 
# }
# NOT RUN {
…
# }
# NOT RUN {
)
}

ternary(Skye/100, ord=c(1,3,2))
# }
Documentation reproduced from package MASS, version 7.3-51.1, License: GPL-2 | GPL-3

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