"owin" of package spatstat and
"gpc.poly" of package rgeos
(originally from gpclib).
Support for the "gpc.poly" class was dropped from
spatstat as of version 1.34-0.owin2gpc(object)gpc2owin(object, ...)
# S3 method for gpc.poly
as.owin(W, ...)
"gpc.poly" or "owin",
respectively.owin."gpc.poly"."gpc.poly" or "owin",
respectively. If neither package rgeos nor gpclib are available,
owin2gpc will just return the pts slot of the
"gpc.poly" (no formal class) with a warning.xylist, and the package rgeos for
conversions of "gpc.poly" objects from and to sp's
"" class.