# Add Cross-Hairs to a Ternary Plot

Source:`R/AllGenerics.R`

, `R/ternary_crosshairs.R`

`ternary_crosshairs.Rd`

Draw lines that intersect at a point.

## Usage

```
ternary_crosshairs(x, y, z, ...)
# S4 method for numeric,numeric,numeric
ternary_crosshairs(x, y, z, x_mark = TRUE, y_mark = TRUE, z_mark = TRUE, ...)
# S4 method for ANY,missing,missing
ternary_crosshairs(x, x_mark = TRUE, y_mark = TRUE, z_mark = TRUE, ...)
```

## Arguments

- x, y, z
A

`numeric`

vector giving the x, y and z ternary coordinates of a set of points. If`y`

and`z`

are missing, an attempt is made to interpret`x`

in a suitable way (see`grDevices::xyz.coords()`

).- ...
Further graphical parameters (see

`graphics::par()`

) may also be supplied as arguments, particularly, line type,`lty`

, line width,`lwd`

and color,`col`

. Also the line characteristics`lend`

,`ljoin`

and`lmitre`

.- x_mark, y_mark, z_mark
A

`logical`

scalar: should the`x`

,`y`

or`z`

axis component be drawn?

## See also

Other geometries:
`ternary_arrows()`

,
`ternary_labels()`

,
`ternary_lines()`

,
`ternary_points()`

,
`ternary_polygon()`

,
`ternary_segments()`

,
`ternary_text()`

## Examples

```
## Add cross-hairs
## Data from Aitchison 1986
ternary_plot(lava, panel.first = ternary_grid())
ternary_crosshairs(lava)
ternary_plot(lava, panel.first = ternary_grid())
ternary_crosshairs(lava, y_mark = FALSE, z_mark = FALSE, col = "red")
ternary_plot(lava, panel.first = ternary_grid())
ternary_crosshairs(lava, x_mark = FALSE, z_mark = FALSE, col = "green")
ternary_plot(lava, panel.first = ternary_grid())
ternary_crosshairs(lava, x_mark = FALSE, y_mark = FALSE, col = "blue")
```