spatstat (version 1.23-1)

as.polygonal: Convert a Window to a Polygonal Window

Description

Given a window W of any geometric type (rectangular, polygonal or binary mask), this function returns a polygonal window that represents the same spatial domain.

Usage

as.polygonal(W)

Arguments

W

A window (object of class "owin").

Value

• A polygonal window (object of class "owin" and of type "polygonal").

Details

Given a window W of any geometric type (rectangular, polygonal or binary mask), this function returns a polygonal window that represents the same spatial domain.

If W is already polygonal, it is returned without change.

If W is a rectangle, it is converted to a polygon with 4 vertices.

If W is a binary mask, then each pixel in the mask is replaced by a small square or rectangle, and the union of these squares or rectangles is computed. The result is a polygonal window that has only horizontal and vertical edges. (Use simplify.owin to remove the staircase appearance, if desired).

See Also

owin, as.owin, as.mask, simplify.owin

Examples

data(letterR)
   m <- as.mask(letterR, dimyx=32)
   p <- as.polygonal(m)
   if(interactive()) {
      plot(m)
      plot(p, add=TRUE, lwd=2)
   }