Identify points in a plot, similarly to the `identify`

function
in base graphics.

```
identify3d(x, y = NULL, z = NULL, labels = seq_along(x), n = length(x),
plot = TRUE, adj = c(-0.1, 0.5), tolerance = 20,
buttons = c("right", "middle"))
```

## Arguments

x, y, z |
coordinates of points in a scatter plot. Alternatively, any
object which defines coordinates (see `xyz.coords` )
can be given as `x` , and `y` and `z` left missing. |

labels |
an optional character vector giving labels for the
points. Will be coerced using `as.character` , and
recycled if necessary to the length of `x` . |

n |
the maximum number of points to be identified. |

plot |
logical: if `plot` is `TRUE` , the labels are
printed near the points and if `FALSE` they are omitted. |

adj |
numeric vector to use as `adj` parameter to
`text3d` when plotting the labels. |

tolerance |
the maximal distance (in pixels)
for the pointer to be ‘close enough’ to a point. |

buttons |
a length 1 or 2 character vector giving the buttons
to use for selection and quitting. |

## Details

If `buttons`

is length 1, the user can quit by reaching `n`

selections, or by hitting the
escape key, but the result will be lost if escape is used.

## Value

A vector of selected indices.

## Author

Duncan Murdoch

## See also