This italy database comes from the NUTS III (Tertiary Administrative Units of the European Community) database of the United Nations Environment Programme (UNEP) GRID-Geneva data sets. These were prepared around 1989, and so may be somewhat out of date.
Users of data sets supplied through UNEP/GRID are requested to incorporate in output products and reports acknowledgements to the originator of the data and to the fact that they were acquired through UNEP/GRID. Appropriate wording may be "UNESCO (1987) through UNEP/GRID-Geneva".
The data file is merely a character string which
specifies the name of an environment variable which contains the
base location of the binary files used by the map drawing functions.
This environment variable (
R_MAP_DATA_DIR for the datasets in the
maps package) is set at package load time if it does not
already exist. Hence setting the environment variable before loading
the package can override the default location of the binary datasets.
Richard A. Becker, and Allan R. Wilks, "Maps in S", AT&T Bell Laboratories Statistics Research Report [93.2], 1993.
Richard A. Becker, and Allan R. Wilks, "Constructing a Geographical Database", AT&T Bell Laboratories Statistics Research Report [95.2], 1995.