Plot 2D confidence ellipses for a series of groups — ellipses_by_group_2D • morphospace

Plot confidence ellipses for different groups in 2D scatterplots created using the generic graphics::plot() function. Used internally (mostly).

ellipses_by_group_2D(
  xy,
  fac,
  col = seq_len(nlevels(fac)),
  lty = 1,
  conflev = 0.95,
  alpha = 0,
  ...
)

Arguments

xy: Coordinates of the scatterplot.
fac: A factor grouping data points.
col: A vector (either character or numeric) indicating the colors used for each group.
lty: A numeric vector indicating the type of line used to draw ellipses.
conflev: Numeric, specifying the confidence level for drawing ellipses.
alpha: Numeric; transparency factor for ellipses.
...: Further arguments passed to graphics::polygon().

See also

hulls_by_group_2D, ellipse

Examples

#load landmark data and necessary packages
library(geomorph)
data("wings")
shapes <- wings$shapes
species <- wings$data$species

#perform PCA
pca <- prcomp(two.d.array(shapes))

#plot and add 95% confidence ellipses
plot(pca$x)
ellipses_by_group_2D(pca$x, fac = species, col = "black", conflev = 0.95)