R: Bivariate histogram

hist2 {squash} | R Documentation

## Bivariate histogram

### Description

Calculate data for a bivariate histogram and (optionally) plot it as a colorgram.

### Usage

    hist2(x, y = NULL,
          nx = 50, ny = nx,
          xlim = NULL, ylim = NULL,
          xbreaks = NULL, ybreaks = NULL,
          plot = TRUE,
          xlab = NULL, ylab = NULL, zlab = "Counts",
          colFn = heat, breaks = prettyInt, ...)

### Arguments

`x, y` | Numeric vectors.
`nx, ny` | Approximate number of intervals along x and y axes.
`xlim, ylim` | Limit the range of data points considered.
`xbreaks, ybreaks` | Breakpoints between bins along x and y axes.
`plot` | Plot the histogram?
`xlab, ylab` | Axis labels.
`zlab` | Label for the color key.
`colFn, breaks` | Color key parameters; see `makecmap`.
`...` | Further arguments passed to `colorgram`.

### Details

Data can be passed to `hist2` in any form recognized by `xy.coords` (e.g. individual vectors, list, data frame, formula).

### Value

Invisibly, a list with components:

`x` | Vector of breakpoints along the x-axis.
`y` | Vector of breakpoints along the y-axis.
`z` | Matrix of counts.
`xlab` | A label for the x-axis.
`ylab` | A label for the y-axis.
`zlab` | A label for the color key.

### See Also

`hist`, for a standard (univariate) histogram.

`hist2d` in the gplots package for another implementation.

The hexbin package, for a hexagonal implementation.

### Examples

      set.seed(123)
      x <- rnorm(10000)
      y <- rnorm(10000) + x
      hist2(x, y)

      ## pseudo-log-scale color breaks:
      hist2(x, y, breaks = prettyLog, key.args = list(stretch = 4))

      ## log-scale color breaks; the old way using 'base'
      ## (notice box removal to make space for the vertical color key)
      hist2(x, y, base = 2, key = vkey, nz = 5, bty = 'l')

[Package squash version 1.0.8 Index]