circular_qqplot function

Quantile-Quantile Linearised Plot for Circular Distributions

Uniformly distributed orientations should yield a straight line through the origin. Systematic departures from linearity will indicate preferred orientation.

circular_qqplot(
  x,
  axial = TRUE,
  xlab = paste("i/(n+1)"),
  ylab = NULL,
  main = "Circular Quantile-Quantile Plot",
  add_line = TRUE,
  col = "#B63679FF",
  ...
)

Arguments

• x: numeric. Angles in degrees
• axial: Logical. Whether data are uniaxial (axial=FALSE)
• xlab, ylab, main: plot labels.
• add_line: logical. Whether to connect the points by straight lines?
• col: color for the dots.
• ...: graphical parameters

Returns

plot

Examples

# von Mises distribution
x_vm <- rvm(100, mean = 0, kappa = 2)
circular_qqplot(x_vm, pch = 20)

x_norm <- rnorm(100, mean = 0, sd = 25)
circular_qqplot(x_norm, pch = 20)

# uniform (random) data
x_unif <- runif(100, 0, 360)
circular_qqplot(x_unif, pch = 20)

References

Borradaile, G. J. (2003). Statistics of earth science data: their distribution in time, space, and orientation (Vol. 351, p. 329). Berlin: Springer.