trifield (version 1.0)

plot.trifield: Plot a ternary field

Description

A simple wrapper around image and contour for plotting ternary fields

Usage

## S3 method for class 'trifield':
plot(x, contours = TRUE, col = topo.colors(256), lab1 = "A = 0", lab2 = "B = 0", lab3 = "C = 0", tribox = TRUE, axis.lines = TRUE, ...)

Arguments

x

An object of class trifield

contours

Make contours?

col

Color palette to use

lab1

First axis label

lab2

Second axis label

lab3

Third axis label

tribox

Draw a triangle around the plot?

axis.lines

Draw internal (altitute) axis lines?

...

Additional graphics parameters to be passed to plot

Value

• None

Details

This is a small demo function showing how one can make a ternary contour plot from a trifield object. The input object can be any list with x, y and z fields, but the result will be odd if non-NA z-values fall outside an equilateral triangle with unit altitude.

See Also

plot.default, image.default, contour.default

Examples

## The function is currently defined as
function(x, contours = TRUE,
                         col = topo.colors(256),
                         lab1 = 'A = 0', lab2 = 'B = 0',
                         lab3 = 'C = 0', tribox = TRUE,
                         axis.lines = TRUE, ...)
{
	lx = 2 / sqrt(3)
	plot(range(x$x), range(x$y), type = 'n', asp = 1,
		 axes = F, xlab = NA, ylab = NA, xpd = NA, ...)
	image(x, col = col, add = TRUE)
	if ( axis.lines ) triaxes()
	if ( contours ) contour(x, add = TRUE)
	if ( !is.na(lab1) )
		text(lx / 6 - 0.06, 1 / 3, lab3, srt = 60)
	if ( !is.na(lab2) )
		text(2 * lx / 3 + 0.06, 2 / 3, lab2, srt = -60)
	if ( !is.na(lab3) )
		text(2 * lx / 3, -0.06, lab1)
	if ( tribox ) tribox(lwd = 3)
  }