ggplot2 (version 0.9.1)

geom_errorbar: Error bars.

Description

Error bars.

Usage

geom_errorbar(mapping = NULL, data = NULL,
    stat = "identity", position = "identity", ...)

Arguments

mapping

The aesthetic mapping, usually constructed with aes or aes_string. Only needs to be set at the layer level if you are overriding the plot defaults.

data

A layer specific dataset - only needed if you want to override the plot defaults.

stat

The statistical transformation to use on the data for this layer.

position

The position adjustment to use for overlappling points on this layer

...

other arguments passed on to layer. This can include aesthetics whose values you want to set, not map. See layer for more details.

See Also

geom_pointrange: range indicated by straight line, with point in the middle; geom_linerange: range indicated by straight line; geom_crossbar: hollow bar with middle indicated by horizontal line; stat_summary: examples of these guys in use, geom_smooth for continuous analog

Examples

# Create a simple example dataset
df <- data.frame(
  trt = factor(c(1, 1, 2, 2)),
  resp = c(1, 5, 3, 4),
  group = factor(c(1, 2, 1, 2)),
  se = c(0.1, 0.3, 0.3, 0.2)
)
df2 <- df[c(1,3),]

# Define the top and bottom of the errorbars
limits <- aes(ymax = resp + se, ymin=resp - se)

p <- ggplot(df, aes(fill=group, y=resp, x=trt))
p + geom_bar(position="dodge", stat="identity")

# Because the bars and errorbars have different widths
# we need to specify how wide the objects we are dodging are
dodge <- position_dodge(width=0.9)
p + geom_bar(position=dodge) + geom_errorbar(limits, position=dodge, width=0.25)

p <- ggplot(df2, aes(fill=group, y=resp, x=trt))
p + geom_bar(position=dodge)
p + geom_bar(position=dodge) + geom_errorbar(limits, position=dodge, width=0.25)

p <- ggplot(df, aes(colour=group, y=resp, x=trt))
p + geom_point() + geom_errorbar(limits, width=0.2)
p + geom_pointrange(limits)
p + geom_crossbar(limits, width=0.2)

# If we want to draw lines, we need to manually set the
# groups which define the lines - here the groups in the
# original dataframe
p + geom_line(aes(group=group)) + geom_errorbar(limits, width=0.2)