In Hans Rosling’s attractive talk Debunking third-world myths with the best stats you've ever seen, he used a lot of bubble plots to illustrate trends
behind the data over time. This function gives an imitation of those moving
bubbles, besides, as this function is based on symbols, we can
also make use of other symbols such as squares, rectangles, thermometers,
etc.
Suppose we have observations of \(n\) individuals over
ani.options('nmax') years. In this animation, the data of each year
will be shown in the bubbles (symbols) plot; as time goes on, certain trends
will be revealed (like those in Rosling’s talk). Please note that the
arrangement of the data for bubbles (symbols) should be a matrix like
\(A_{ijk}\) in which \(i\) is the individual id (from 1 to n), \(j\)
denotes the \(j\)-th variable (from 1 to p) and \(k\) indicates the time
from 1 to ani.options('nmax').
And the length of x and y should be equal to the number of rows
of this matrix.
library(animation)
ani.options(interval = 0.2, nmax = 50)
## use default arguments (random numbers); you may try to find the real data
par(mar = c(4, 4, 0.2, 0.2))
Rosling.bubbles()
## rectangles
Rosling.bubbles(type = "rectangles", data = matrix(abs(rnorm(50 * 10 * 2)), ncol = 2))