coerce-gpc-methods {polyCub}

Conversion between polygonal "owin" and "gpc.poly"

Description

Package polyCub implements converters between the classes "owin" of package spatstat.geom and "gpc.poly" of package gpclib.

Usage

owin2gpc(object)

gpc2owin(object, ...)

as.owin.gpc.poly(W, ...)

Arguments

object

an object of class "gpc.poly" or "owin", respectively.

...

further arguments passed to owin.

W

an object of class "gpc.poly".

Value

The converted polygon of class "gpc.poly" or "owin", respectively. If package gpclib is not available, owin2gpc will just return the pts slot of the "gpc.poly" (no formal class) with a warning.

Note

The converter owin2gpc requires the package 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!

Author(s)

Sebastian Meyer

See Also

xylist

Examples

## use example polygons from
example(plotpolyf, ask = FALSE)
letterR  # a simple "xylist"

letterR.owin <- spatstat.geom::owin(poly = letterR)
letterR.gpc_from_owin <- owin2gpc(letterR.owin)
## warns if "gpclib" is unavailable

if (is(letterR.gpc_from_owin, "gpc.poly")) {
  letterR.xylist_from_gpc <- xylist(letterR.gpc_from_owin)
  stopifnot(all.equal(letterR, lapply(letterR.xylist_from_gpc, `[`, 1:2)))
  letterR.owin_from_gpc <- gpc2owin(letterR.gpc_from_owin)
  stopifnot(all.equal(letterR.owin, letterR.owin_from_gpc))
}