Extracting GSHHS global coastlines

which uses threshold= to filter out boundary slivers. Maybe even easier is
the maps package and map2SpatialPolygons() in maptools if all you need is
a background world land map.

And even better, and almost just as easy, is to use the vector data from 
"http://www.naturalearthdata.com/". These are free (license: public domain), 
detailed, very high quality and up-to-date (whereas the maps in the maps and 
mapdata packages still contain USSR and other countries that don?t exist 
anymore).

Karl Ove Hufthammer
E-mail: karl at huftis.org
Jabber: huftis at jabber.no