spatstat (version 1.11-4)

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

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