# triax.plot

##### Triangle plot

Display a triangle plot with optional grid.

- Keywords
- misc

##### 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.

##### Value

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

##### 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.

##### See Also

##### Examples

```
# NOT RUN {
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)
# }
```

*Documentation reproduced from package plotrix, version 3.7, License: GPL (>= 2)*