map: either a matrix or data.frame with two columns, a list with components x and y, or an object of any class that can be used for maps and provides its own plot method (e.g., "SpatialPolygons" from package sp). A list of the previously mentioned types can also be provided.
add: a logical indicating whether map should be added to an already existing plot (the default is FALSE).
...: further arguments and graphical parameters to be passed to plot and/or graphics::lines().
M. Templ, A. Alfons, P. Filzmoser (2012) Exploring incomplete data using visualization tools. Journal of Advances in Data Analysis and Classification, Online first. DOI: 10.1007/s11634-011-0102-y.