Conversion between polygonal "owin" and "gpc.poly"
owin2gpc(object) gpc2owin(object, ...) as.owin.gpc.poly(W, ...)
object |
an object of class |
... |
further arguments passed to |
W |
an object of class |
The converted polygon of class "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.
The converter owin2gpc
requires the package rgeos (or
gpclib) for the formal class definition of a "gpc.poly"
.
It will produce vertices ordered according to the sp convention,
i.e. clockwise for normal boundaries and anticlockwise for holes, where,
however, the first vertex is not repeated!
Sebastian Meyer
xylist
, and the package rgeos for
conversions of "gpc.poly"
objects from and to sp's
"SpatialPolygons"
class.
if (require("rgeos") && require("spatstat.geom")) { ## use example polygons from example(plotpolyf, ask = FALSE) letterR # a simple "xylist" letterR.owin <- owin(poly = letterR) letterR.gpc_from_owin <- owin2gpc(letterR.owin) letterR.xylist_from_gpc <- xylist(letterR.gpc_from_owin) stopifnot(all.equal(letterR, lapply(letterR.xylist_from_gpc, "[", 1:2))) letterR.owin_from_gpc <- as.owin(letterR.gpc_from_owin) stopifnot(all.equal(letterR.owin, letterR.owin_from_gpc)) }
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