US 2000 Presidential Election Movie: straightening scatter plots

A movie to illustrate the effects of the transformation of variable(s) on the appearance of a scatter plot, using the 2000 U.S. Presidential Election data from Florida.

Usage

scatterplot_movie(
  x,
  y,
  delta_power = 0.1,
  pos = 1,
  envir = as.environment(pos),
  ...
)

Arguments

x, y: Numeric vectors of the same length. Pairs of values to plot using a scatter plot. The values in x will be plotted on the horizontal axis, the values in y on the vertical axis.
delta_power: A numeric scalar. The amount by which the powers of x and y increase/decrease after one click of a button in the parameter window.
pos: A numeric integer. Used in calls to assign to make information available across successive frames of a movie. By default, uses the current environment.
envir: An alternative way (to pos) of specifying the environment. See environment.
...: Further arguments to be passed to plot.

Value

Nothing is returned, only the animation is produced.

Details

scatterplot_movie produces a scatter plot of the input variables x and y which can then be animated by transforming x and/or y using power transformations. [In fact a Box-Cox transformation is used.] The power of x and y is chosen using a parameter windows containing buttons labelled + and -. Clicking + increases the power by delta_power and clicking - decreases the power by delta_power.

Examples

# Proportion of votes gained by Buchanan
pbuch <- 100 * USelection$buch / USelection$tvot

# Produce plot
scatterplot_movie(x = USelection$npop, y = pbuch)

# Change the plotting character
scatterplot_movie(x = USelection$npop, y = pbuch, pch = 16)


# Identify Palm Beach using a different plotting character
county_name <- USelection[, "co_names"]
pb <- which(county_name == "PalmBeach")
my_pch <- rep(16, length(county_name))
my_pch[pb] <- 4
scatterplot_movie(x = USelection$npop, y = pbuch, pch = my_pch)