Tools for working with polygons with holes in 'ggplot2', with a new 'geom' for drawing a 'polypath' applying the 'evenodd' or 'winding' rules.
ggplot2 geom for polygons with holes, called 'geom_polypath'.
Install from CRAN.
Install the development version.
See the vignette for examples.
More examples, and more detail than you probably need can be found here: