R: Extracting Plotting Structures

xyz.coords {grDevices} | R Documentation

## Extracting Plotting Structures

### Description

Utility for obtaining consistent x, y and z coordinates and labels for three dimensional (3D) plots.

### Usage

    xyz.coords(x, y = NULL, z = NULL,
               xlab = NULL, ylab = NULL, zlab = NULL,
               log = NULL, recycle = FALSE)

### Arguments

`x, y, z` | the x, y and z coordinates of a set of points. Both `y` and `z` can be left at `NULL`. In this case, an attempt is made to interpret `x` in a way suitable for plotting. If the argument is a formula `zvar ~ xvar + yvar`, `xvar`, `yvar` and `zvar` are used as x, y and z variables; if the argument is a list containing components `x`, `y` and `z`, these are assumed to define plotting coordinates; if the argument is a matrix or `data.frame` with three or more columns, the first is assumed to contain the x values, the 2nd the y ones, and the 3rd the z ones – independently of any column names that `x` may have. Alternatively two arguments `x` and `y` can be provided (leaving `z = NULL`). One may be real, the other complex; in any other case, the arguments are coerced to vectors and the values plotted against their indices.
`xlab, ylab, zlab` | names for the x, y and z variables to be extracted.
`log` | character, `"x"`, `"y"`, `"z"` or combinations. Sets negative values to `NA` and gives a warning.
`recycle` | logical; if `TRUE`, recycle (`rep`) the shorter ones of `x`, `y` or `z` if their lengths differ.

### Value

A list with the components

`x` | numeric (i.e., `double`) vector of abscissa values.
`y` | numeric vector of the same length as `x`.
`z` | numeric vector of the same length as `x`.
`xlab` | `character(1)` or `NULL`, the axis label of `x`.
`ylab` | `character(1)` or `NULL`, the axis label of `y`.
`zlab` | `character(1)` or `NULL`, the axis label of `z`.

### Author(s)

Uwe Ligges and Martin Maechler

### See Also

`xy.coords` for 2D.

### Examples

    xyz.coords(data.frame(10*1:9, -4), y = NULL, z = NULL)

    xyz.coords(1:6, stats::fft(1:6), z = NULL, xlab = "X", ylab = "Y")

    y <- 2 * (x2 <- 10 + (x1 <- 1:10))
    xyz.coords(y ~ x1 + x2, y = NULL, z = NULL)

    xyz.coords(data.frame(x = -1:9, y = 2:12, z = 3:13), y = NULL, z = NULL,
               log = "xy")
    ##> Warning message: 2 x values <= 0 omitted ...

[Package grDevices version 2.6.2 Index]