3 \title{Add a Scale Bar to a Phylogeny Plot}
5 add.scale.bar(x, y, length = NULL, ask = FALSE,
6 lwd = 1, lcol = "black", ...)
9 \item{x}{x location of the bar (can be left missing).}
10 \item{y}{y location of the bar (can be left missing).}
11 \item{length}{a numeric value giving the length of the scale bar. If
12 none is supplied, a value is calculated from the data.}
13 \item{ask}{a logical; if \code{TRUE} the user is asked to click where
14 to draw the bar. The default is \code{FALSE}.}
15 \item{lwd}{the width of the bar.}
16 \item{lcol}{the colour of the bar (use \code{col} for the colour of
18 \item{\dots}{further arguments to be passed to \code{text}.}
21 This function adds a horizontal bar giving the scale of the branch
22 lengths to a plot of a phylogenetic tree on the current graphical
26 By default, the bar is placed in a corner of the graph depending on
27 the direction of the tree. Otherwise both \code{x} and \code{y} must
28 be specified (if only one is given it is ignored).
30 The further arguments (\code{\dots}) are used to format the text. They
31 may be \code{font}, \code{cex}, \code{col}, and so on (see examples
32 below, and the help page on \code{\link[graphics]{text}}).
34 The function \code{\link[graphics]{locator}} may be used to
35 determine the \code{x} and \code{y} arguments.
37 \author{Emmanuel Paradis}
39 \code{\link{plot.phylo}}, \code{\link{axisPhylo}},
40 \code{\link[graphics]{locator}}
44 layout(matrix(1:2, 2, 1))
48 add.scale.bar(cex = 0.7, font = 2, col = "red")