dynamitePlot.R

# This function creates a bar plot with error bars, frequently termed a "dynamite plot". 
# Created by Samuel Brown 6 April 2012
# http://www.the-praise-of-insects.blogspot.com

# height = numeric vector giving the heights for the barplot
# error = numeric vector of errors for plotting the error bars
# names = character vector giving the names for the x axis
# significance = character vector giving the labels denoting significance
# ylim = range shown on the y axis

dynamitePlot <- function(height, error, names = NA, significance = NA, ylim = c(0,maxLim), ...){
	maxLim <- 1.1* max(mapply(sum, height, error))
	bp <- barplot(height, names.arg = names, ylim = ylim, ...)
	arrows(x0 = bp, y0 = height, y1 = height + error, angle = 90)
	text(x = bp, y = 0.2 + height + error, labels = significance)
}

# Examples:
#   Values <- c(1,2,5,4)
#   Errors <- c(0.25, 0.5, 0.33, 0.12)
#   Names <- paste("Trial", 1:4)
#   Sig <- c("a", "a", "b", "b")

#   dynamitePlot(Values, Errors, names = Names, significance = Sig)