New package: gpclib

Roger Peng rpeng at
Wed Jan 8 17:48:05 CET 2003

I have just uploaded a package to CRAN called `gpclib' for clipping large
and complex polygons.  This package provides an R interface to Alan
Murta's very fast General Polygon Clipper library (written in C), which
has an optimized version of the Vatti algorithm. Not all features of
Murta's library are implemented -- right now you can do intersections,
differences, and unions.  There are also functions for reading/writing
from/to files and coercing between various data types.

For some more details about the package see

Please send any comments, complaints, and bug reports to
rpeng at

Here is the DESCRIPTION file for the package:

Package:  gpclib
Version:  1.0
Date:  1/6/2003
Depends:  R (>= 1.6.1)
Title:  General Polygon Clipping Library for R
Author:  R interface by Roger D. Peng <rpeng at>; GPC library
	 by Alan Murta
Maintainer:  Roger D. Peng <rpeng at>
Description:  General polygon clipping routines for R based on Alan
	      Murta's C library
License:  Code written by R. D. Peng is available under the LGPL; the C
	  code for the GPC library is free for non-commercial use (see the
	  files `gpc.c' and `gpc.h' for details)

Happy clipping!

UCLA Department of Statistics
rpeng at

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