Adds an axis to the current plot.

## Arguments

- side
An

`integer`

specifying which side of the plot the axis is to be drawn on. The axis is placed as follows: 1=below, 2=right and 3=left.- at
A

`numeric`

vector giving the points at which tick-marks are to be drawn.- labels
A

`logical`

scalar specifying whether (numerical) annotations are to be made at the tickmarks, or a`character`

vector of labels to be placed at the tickpoints. If this is not`logical`

,`at`

should also be supplied and of the same length.- tick
A

`logical`

scalar: should tickmarks and an axis line be drawn?- center
A

`numeric`

vector giving the center. If`NULL`

(the default), data are assumed not centered.- scale
A

`numeric`

vector giving the scale factor. If`NULL`

(the default), data are assumed not scaled.- font
font for text. Defaults to

`par("font.axis")`

.- lty
A

`character`

string or`numeric`

value specifying the line type for both the axis line and the tick marks.- lwd, lwd.ticks
A non-negative

`numeric`

value specifying the line widths for the axis line and the tick marks.- col, col.ticks
Colors for the axis line and the tick marks respectively. Defaults to

`par("col.axis")`

.- ...
Other graphical parameters may also be passed as arguments to this function, particularly,

`cex.axis`

,`col.axis`

and`font.axis`

for axis annotation.

## See also

Other graphical elements:
`ternary_box()`

,
`ternary_grid()`

,
`ternary_pairs()`

,
`ternary_plot()`

,
`ternary_title()`

## Examples

```
## Add axis
ternary_plot(NULL, axes = FALSE)
ternary_axis(side = 1, col = "red")
ternary_axis(side = 2, col = "blue")
ternary_axis(side = 3, col = "green")
## Add box and grid
ternary_plot(NULL, axes = FALSE)
ternary_box(lty = "dashed", col = "red")
ternary_grid(lty.primary = "dotted")
```