pyramid.plot: Pyramid plot

In plotrix: Various Plotting Functions

Pyramid plot

Description

Displays a pyramid (opposed horizontal bar) plot on the current graphics device.

Usage

 pyramid.plot(lx,rx,labels=NULL,top.labels=c("Male","Age","Female"),
  main="",laxlab=NULL,raxlab=NULL,unit="%",lxcol,rxcol,gap=1,space=0.2,
  ppmar=c(4,2,4,2),labelcex=1,add=FALSE,xlim,show.values=FALSE,ndig=1,
  do.first=NULL)

Arguments

lx,rx	Vectors or a matrix or data frame (see Details) which should be of equal length.
labels	Labels for the categories represented by each pair of bars. There should be a label for each lx or rx value, even if empty. If ‘⁠labels⁠’ is a matrix or data frame, the first two columns will be used for the left and right category labels respectively.
top.labels	The two categories represented on the left and right sides of the plot and a heading for the labels in the center.
main	Optional title for the plot.
laxlab	Optional labels for the left x axis ticks.
raxlab	Optional labels for the right x axis ticks.
unit	The label for the units of the plot.
lxcol,rxcol	Color(s) for the left and right sets of bars. Both of these default to ‘⁠rainbow(length(labels))⁠’.
gap	One half of the space between the two sets of bars for the ‘⁠labels⁠’ in user units.
space	Space between the bars. Should be 0 <= space < 1.
ppmar	Margins for the plot (see Details).
labelcex	Expansion for the category labels.
add	Whether to add bars to an existing plot. Usually this involves overplotting a second set of bars, perhaps transparent.
xlim	Optional x limit for the plot (see Details).
show.values	Whether to display ‘⁠lx⁠’ and ‘⁠rx⁠’ at the ends of the bars.
ndig	The number of digits to round the values if displayed.
do.first	Optional expression to evaluate before displaying anything.

Details

‘⁠pyramid.plot⁠’ is principally intended for population pyramids, although it can display other types of opposed bar charts with suitable modification of the arguments. If the user wants a different unit for the display, just change ‘⁠unit⁠’ accordingly. The default gap of two units is usually satisfactory for the four to six percent range of most bars on population pyramids. If ‘⁠labels⁠’ is a matrix or data frame of at least two columns, the first column will be displayed on the on the left side of the gap in the center, and the second on the right. This will almost always require increasing the gap width and perhaps also specifying a wider plotting device. Displaying the values will usually require increasing the left and/or right margins of the plot, or setting ‘⁠xlim⁠’ larger than the largest value.

If a gap width of zero is passed, the category labels will be displayed at the left and right extents of the plot. This usually requires setting ‘⁠xlim⁠’ to values larger than the maximum extent of ‘⁠lx⁠’ and ‘⁠rx⁠’. The user can pass two different values to ‘⁠xlim⁠’, but this is almost always a bad idea, as the lengths of the bars will not be in the same proportion to the values on the left and right sides. Both the bars and category labels are vertically centered on integer values, allowing the user to easily add components to the plot.

‘⁠lx⁠’ and ‘⁠rx⁠’ are the values specifying the left and right extents of the left and right bars respectively. If both are matrices or data frames, ‘⁠pyramid.plot⁠’ will produce opposed stacked bars with the first columns innermost. In this mode, colors are limited to one per column. The stacked bar mode will in general not work with the ‘⁠add⁠’ method or with a gap of zero. Note that the stacked bar mode can get very messy very quickly.

The ‘⁠add⁠’ argument allows one or more sets of bars to be plotted on an existing plot. If these are not transparent, any bar that is shorter than the bar that overplots it will disappear. Only some graphic devices (e.g. ‘⁠pdf⁠’) will handle transparency.

In order to add bars, the function cannot restore the initial margin values or the new bars will not plot properly. To automatically restore the plot margins, call the function as in the example.

Value

The return value of ‘⁠par("mar")⁠’ when the function was called.

Author(s)

Jim Lemon (thanks to Susumu Tanimura for the patch that omits ticks for NA values in vector input and Igor Rebeiro for the space argument)

See Also

rect

Examples

 xy.pop<-c(3.2,3.5,3.6,3.6,3.5,3.5,3.9,3.7,3.9,3.5,3.2,2.8,2.2,1.8,
  1.5,1.3,0.7,0.4)
 xx.pop<-c(3.2,3.4,3.5,3.5,3.5,3.7,4,3.8,3.9,3.6,3.2,2.5,2,1.7,1.5,
  1.3,1,0.8)
 agelabels<-c("0-4","5-9","10-14","15-19","20-24","25-29","30-34",
  "35-39","40-44","45-49","50-54","55-59","60-64","65-69","70-74",
  "75-79","80-44","85+")
 mcol<-color.gradient(c(0,0,0.5,1),c(0,0,0.5,1),c(1,1,0.5,1),18)
 fcol<-color.gradient(c(1,1,0.5,1),c(0.5,0.5,0.5,1),c(0.5,0.5,0.5,1),18)
 par(mar=pyramid.plot(xy.pop,xx.pop,labels=agelabels,
  main="Australian population pyramid 2002",lxcol=mcol,rxcol=fcol,
  gap=0.5,show.values=TRUE))
 # three column matrices
 avtemp<-c(seq(11,2,by=-1),rep(2:6,each=2),seq(11,2,by=-1))
 malecook<-matrix(avtemp+sample(-2:2,30,TRUE),ncol=3)
 femalecook<-matrix(avtemp+sample(-2:2,30,TRUE),ncol=3)
 # group by age
 agegrps<-c("0-10","11-20","21-30","31-40","41-50","51-60",
  "61-70","71-80","81-90","91+")
 oldmar<-pyramid.plot(malecook,femalecook,labels=agegrps,
  unit="Bowls per month",lxcol=c("#ff0000","#eeee88","#0000ff"),
  rxcol=c("#ff0000","#eeee88","#0000ff"),laxlab=c(0,10,20,30),
  raxlab=c(0,10,20,30),top.labels=c("Males","Age","Females"),gap=4,
  do.first="plot_bg(\"#eedd55\")")
 # put a box around it
 box()
 # give it a title
 mtext("Porridge temperature by age and sex of bear",3,2,cex=1.5)
 # stick in a legend
 legend(par("usr")[1],11,c("Too hot","Just right","Too cold"),
  fill=c("#ff0000","#eeee88","#0000ff"))
 # don't forget to restore the margins and background
 par(mar=oldmar,bg="transparent")

plotrix documentation built on Nov. 10, 2023, 5:07 p.m.