Pie diagrams are not often used to present scientific data because the human eye is not very good at comparing angular proportions. The more complicated, exploded sector, elliptical, and 3-dimensional pie diagrams are especially misleading because some parts appear to have much larger areas than is rightly theirs. Linear plots, although less exciting visually, are much easier to interpret.

The following code produces much the same sort of result using R.

h=3.8;windows(height=h,width=1.2*h) par(cex=.7) pie(c(59,14,18,7,2), clockwise=TRUE, main='Reasons for subsistence hunting', labels=c('Direct consumption', 'Bushmeat trade', 'Damage to poultry', 'Damage to crops', 'Others'), col=c('red','green','blue','yellow','white'))

• In this case, we provided the data as percentages. But if we had provided them as counts, this function would automatically convert them to proportions before drawing the graph.

• We specified clockwise=TRUE in order to start the 'slices' at the 12 o'clock mark. The default in R starts at the 3 o'clock mark.

• We have specified the colours to be used; the default values in R are described as 'pastel colours'.

• Three dimensional and elliptical pie diagrams are available in some packages in R, but we do not recommend their use since they are inherently biased.