area.owin

Area of a Window

Computes the area of a window

Usage

area.owin(w)

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

perimeter, diameter, owin.object, as.owin

Aliases

• area.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