R: Enhanced Bar Plots

barplot2 {gplots} | R Documentation

## Enhanced Bar Plots

### Description

An enhancement of the standard barplot() function. Creates a bar plot with vertical or horizontal bars. Can plot confidence intervals for each bar, a lined grid behind the bars, change plot area color and logarithmic axes may be used.

### Usage

    ## Default S3 method:
    barplot2(height, width = 1, space = NULL,
            names.arg = NULL, legend.text = NULL, beside = FALSE,
            horiz = FALSE, density = NULL, angle = 45,
            col = NULL, prcol = NULL, border = par("fg"),
            main = NULL, sub = NULL, xlab = NULL, ylab = NULL,
            xlim = NULL, ylim = NULL, xpd = TRUE, log = "",
            axes = TRUE, axisnames = TRUE,
            cex.axis = par("cex.axis"), cex.names = par("cex.axis"),
            inside = TRUE, plot = TRUE, axis.lty = 0, offset = 0,
            plot.ci = FALSE, ci.l = NULL, ci.u = NULL,
            ci.color = "black", ci.lty = "solid", ci.lwd = 1, ci.width = 0.5,
            plot.grid = FALSE, grid.inc = NULL,
            grid.lty = "dotted", grid.lwd = 1, grid.col = "black",
            add = FALSE, panel.first = NULL, panel.last = NULL, ...)

### Arguments

`height` | either a vector or matrix of values describing the bars which make up the plot. If `height` is a vector, the plot consists of a sequence of rectangular bars with heights given by the values in the vector. If `height` is a matrix and `beside` is `FALSE` then each bar of the plot corresponds to a column of `height`, with the values in the column giving the heights of stacked “sub-bars” making up the bar. If `height` is a matrix and `beside` is `TRUE`, then the values in each column are juxtaposed rather than stacked.
`width` | optional vector of bar widths. Re-cycled to length the number of bars drawn. Specifying a single value will no visible effect unless `xlim` is specified.
`space` | the amount of space (as a fraction of the average bar width) left before each bar. May be given as a single number or one number per bar. If `height` is a matrix and `beside` is `TRUE`, `space` may be specified by two numbers, where the first is the space between bars in the same group, and the second the space between the groups. If not given explicitly, it defaults to `c(0,1)` if `height` is a matrix and `beside` is `TRUE`, and to 0.2 otherwise.
`names.arg` | a vector of names to be plotted below each bar or group of bars. If this argument is omitted, then the names are taken from the `names` attribute of `height` if this is a vector, or the column names if it is a matrix.
`legend.text` | a vector of text used to construct a legend for the plot, or a logical indicating whether a legend should be included. This is only useful when `height` is a matrix. In that case given legend labels should correspond to the rows of `height`; if `legend.text` is true, the row names of `height` will be used as labels if they are non-null.
`beside` | a logical value. If `FALSE`, the columns of `height` are portrayed as stacked bars, and if `TRUE` the columns are portrayed as juxtaposed bars.
`horiz` | a logical value. If `FALSE`, the bars are drawn vertically with the first bar to the left. If `TRUE`, the bars are drawn horizontally with the first at the bottom.
`density` | a vector giving the the density of shading lines, in lines per inch, for the bars or bar components. The default value of `NULL` means that no shading lines are drawn. Non-positive values of `density` also inhibit the drawing of shading lines.
`angle` | the slope of shading lines, given as an angle in degrees (counter-clockwise), for the bars or bar components.
`col` | a vector of colors for the bars or bar components. By default, grey is used if `height` is a vector, and `heat.colors(nrow(height))` if `height` is a matrix.
`prcol` | the color to be used for the plot region.
`border` | the color to be used for the border of the bars.
`main, sub` | overall and sub titles for the plot.
`xlab` | a label for the x axis.
`ylab` | a label for the y axis.
`xlim` | limits for the x axis.
`ylim` | limits for the y axis.
`xpd` | logical. Should bars be allowed to go outside region?
`log` | a character string which contains ‘"x"’ if the x axis is to be logarithmic, ‘"y"’ if the y axis is to be logarithmic and ‘"xy"’ or ‘"yx"’ if both axes are to be logarithmic.
`axes` | logical. If `TRUE`, a vertical (or horizontal, if `horiz` is true) axis is drawn.
`axisnames` | logical. If `TRUE`, and if there are `names.arg` (see above), the other axis is drawn (with `lty = 0`) and labeled.
`cex.axis` | expansion factor for numeric axis labels.
`cex.names` | expansion factor for names.
`inside` | logical. If `TRUE`, the lines which divide adjacent (non-stacked!) bars will be drawn. Only applies when `space = 0` (which it partly is when `beside = TRUE`).

`plot` | logical. If `FALSE`, nothing is plotted.
`axis.lty` | the graphics parameter `lty` applied to the axis and tick marks of the categorical (default horzontal) axis. Note that by default the axis is suppressed.
`offset` | a vector indicating how much the bars should be shifted relative to the x axis.
`plot.ci` | logical. If `TRUE`, confidence intervals are plotted over the bars. Note that if a stacked bar plot is generated, confidence intervals will not be plotted even if `plot.ci = TRUE`
`ci.l,ci.u` | The confidence intervals (ci.l = lower bound, ci.u = upper bound) to be plotted if `plot.ci` = `TRUE`. Values must have the same dim structure as `height`.
`ci.color` | the color for the confidence interval line segments
`ci.lty` | the line type for the confidence interval line segments
`ci.lwd` | the line width for the confidence interval line segments
`ci.width` | length of lines used for the "t" at the end of confidence interval line segments, as a multple of `width`. Defaults to 0.5.
`plot.grid` | if `TRUE` a lined grid will be plotted behind the bars
`grid.inc` | the number of grid increments to be plotted
`grid.lty` | the line type for the grid
`grid.lwd` | the line width for the grid
`grid.col` | the line color for the grid
`add` | logical, if `TRUE` add barplot to current plot.
`panel.first` | An expression to be evaluated after the plot region coordinates have been set up, but prior to the drawing of the bars and other plot region contents. This can be useful to add additional plot region content behind the bars. This will also work if `add` = `TRUE`
`panel.last` | An expression to be evaluated after the bars have been drawn, but prior to the addition of confidence intervals, a legend and the axis annotation
`...` | further graphical parameters (`par`) are passed to `plot.window()`, `title()` and `axis`.

### Details

This is a generic function, it currently only has a default method. A formula interface may be added eventually.

### Value

A numeric vector (or matrix, when `beside = TRUE`), say `mp`, giving the coordinates of all the bar midpoints drawn, useful for adding to the graph.

If `beside` is true, use `colMeans(mp)` for the midpoints of each group of bars, see example.

### Note

Prior to R 1.6.0, `barplot` behaved as if `axis.lty = 1`, unintentionally. 0 (zero) and NA values in `height` will not be plotted if using logarithmic scales. If there are NA values in `height` and `beside = FALSE`, values after the NA will not be plotted in stacked bars.

### Author(s)

Original barplot() by R-Core. Enhancements by Marc Schwartz marc\_schwartz@comcast.net

### See Also

`plot(..., type = "h")`, `dotchart`, `hist`.

### Examples

    tN <- table(Ni <- rpois(100, lambda = 5))
    r <- barplot2(tN, col = 'gray')

    #- type = "h" plotting *is* `bar'plot
    lines(r, tN, type = 'h', col = 'red', lwd = 2)

    barplot2(tN, space = 1.5, axisnames = FALSE,
            sub = "barplot2(..., space = 1.5, axisnames = FALSE)")

    data(VADeaths, package = "datasets")
    barplot2(VADeaths, plot = FALSE)
    barplot2(VADeaths, plot = FALSE, beside = TRUE)

    mp <- barplot2(VADeaths) # default
    tot <- colMeans(VADeaths)
    text(mp, tot + 3, format(tot), xpd = TRUE, col = "blue")
    barplot2(VADeaths, beside = TRUE,
            col = c("lightblue", "mistyrose", "lightcyan",
                    "lavender", "cornsilk"),
            legend = rownames(VADeaths), ylim = c(0, 100))
    title(main = "Death Rates in Virginia", font.main = 4)

    # Example with confidence intervals and grid
    hh <- t(VADeaths)[, 5:1]
    mybarcol <- "gray20"
    ci.l <- hh * 0.85
    ci.u <- hh * 1.15
    mp <- barplot2(hh, beside = TRUE,
            col = c("lightblue", "mistyrose",
                    "lightcyan", "lavender"),
            legend = colnames(VADeaths), ylim = c(0, 100),
            main = "Death Rates in Virginia", font.main = 4,
            sub = "Faked 95 percent error bars", col.sub = mybarcol,
            cex.names = 1.5, plot.ci = TRUE, ci.l = ci.l, ci.u = ci.u,
            plot.grid = TRUE)
    mtext(side = 1, at = colMeans(mp), line = -2,
          text = paste("Mean", formatC(colMeans(hh))), col = "red")
    box()

    # Example with horizontal bars, grid and logarithmic x axis
    barplot2(1:10 , log = "x", plot.grid = TRUE, grid.inc = 10,
            xlim = c(0.5, 20), horiz = TRUE, cex.axis = 0.9,
            prcol = "gray95")
    box()

    # Bar shading example
    barplot2(VADeaths, angle = 15 + 10 * 1:5, density = 20, col = "black",
            legend = rownames(VADeaths))
    title(main = list("Death Rates in Virginia", font = 4))

    # border :
    barplot2(VADeaths, border = "dark blue")

[Package gplots version 3.0.1 Index]