Set of tools for manipulating and reading geographic data, in
particular ESRI shapefiles; C code used from shapelib. It includes
binary access to GSHHS shoreline files. The package also provides
interface wrappers for exchanging spatial objects with packages
such as PBSmapping, spatstat, maps, RArcInfo, Stata tmap, WinBUGS,
Mondrian, and others.

WWW: http://cran.r-project.org/web/packages/maptools/