Triangle plot

Display a triangle plot with optional grid.

Usage

triax.plot(x=NULL,main="",at=seq(0.1,0.9,by=0.1),
 axis.labels=NULL,tick.labels=NULL,col.axis="black",cex.axis=1,
 cex.ticks=1,
 align.labels=TRUE,show.grid=FALSE,col.grid="gray",lty.grid=par("lty"),
 cc.axes=FALSE,show.legend=FALSE,label.points=FALSE,point.labels=NULL,
 col.symbols="black",pch=par("pch"),mar=c(5,2,4,2),no.add=TRUE,...)

Arguments

x

Matrix where each row is three proportions or percentages that must sum to 1 or 100 respectively.

main

The title of the triangle plot. Defaults to nothing.

at

The tick positions on the three axes.

axis.labels

Labels for the three axes in the order left, right, bottom. Defaults to the column names.

tick.labels

The tick labels for the three axes as a list with three components l, r and b (left, right and bottom). Defaults to argument at (proportions).

col.axis

Color of the triangular axes, ticks and labels.

cex.axis

Character expansion for axis labels.

cex.ticks

Character expansion for the tick labels.

align.labels

Logical - whether to align axis and tick labels with the axes.

show.grid

Whether to display grid lines at the ticks.

col.grid

Color of the grid lines. Defaults to gray.

lty.grid

Type of line for the grid.

cc.axes

Whether axes and axis ticks should be clockwise or counterclockwise.

show.legend

Logical - whether to display a legend.

label.points

Logical - whether to call thigmophobe.labels to label the points.

point.labels

Optional labels for the points and/or legend.

col.symbols

Color of the symbols representing each value.

pch

Symbols to use in plotting values.

mar

Margins for the triangle plot.

no.add

Whether to restore the previous plotting parameters (TRUE) or leave them, allowing more points to be added.

...

Additional arguments passed to points.

Details

triax.plot displays a triangular plot area on which proportions or percentages are displayed. A grid or legend may also be displayed.

Note

A three axis plot can only properly display one or more sets of three proportions that each sum to 1 (or percentages that sum to 100). Other values may be scaled to proportions (or percentages), but unless each set of three sums to 1 (or 100), they will not plot properly and triax.points will complain appropriately. Note also that triax.plot will only display properly in a square plot, which is forced by par(pty="s").

In case the user does want to plot values with different sums, the axis tick labels can be set to different ranges to accomodate this. triax.points will still complain, but it will plot the values.

If planning to add points with triax.points call triax.plot with no.add=FALSE and restore plotting parameters after the points are added.

Value

A list containing xypos (the x,y positions plotted) and oldpar (the plotting parameters at the time triax.plot

was called).

Author

Jim Lemon - thanks to Ben Daughtry for the info on counterclockwise axes.

See also

triax.points, triax.abline, thigmophobe.labels

Examples

 data(soils)
 triax.plot(soils[1:10,],main="DEFAULT")

 triax.plot(soils[1:10,],main="PERCENTAGES (Counterclockwise axes)",
  tick.labels=list(l=seq(10,90,by=10),r=seq(10,90,by=10),b=seq(10,90,by=10)),
  pch=3,cc.axes=TRUE)

 triax.return<-triax.plot(soils[1:6,],main="GRID AND LEGEND",
  show.grid=TRUE,show.legend=TRUE,col.symbols=1:6,pch=4)

 # triax.plot changes a few parameters
 par(triax.return$oldpar)