spatstat (version 1.2-1)

area.owin: Area of a Window

Description

Computes the area of a window

Usage

area.owin(w)

Arguments

w

A window, whose area will be computed. This should be an object of class owin, or can be given in any format acceptable to as.owin().

Value

• The numerical value of the area of the window.

Details

If the window W is of type "rectangle" or "polygonal", the area of this rectangular window is computed by analytic geometry. If W is of type "mask" the area of the discrete raster approximation of the window is computed by summing the binary image values and adjusting for pixel size.

See Also

owin.object, as.owin

Examples

library(spatstat)
  w <- unit.square()
  area.owin(w)
       # returns 1.00000

  k <- 6
  theta <- 2 * pi * (0:(k-1))/k
  co <- cos(theta)
  si <- sin(theta)
  mas <- owin(c(-1,1), c(-1,1), poly=list(x=co, y=si))
  area.owin(mas)
      # returns approx area of k-gon
  
  mas <- as.mask(w, eps=0.01)
  X <- raster.x(mas)
  Y <- raster.y(mas)
  mas$m <- ((X - 0.5)^2 + (Y - 0.5)^2 <= 1)
  area.owin(mas)
       # returns 3.14 approx