R: Area of a Window

area.owin {spatstat.geom} | R Documentation

## Area of a Window

### Description

Computes the area of a window

### Usage

     area(w)

     ## S3 method for class 'owin'
    area(w)

     ## Default S3 method:
    area(w)

     ## S3 method for class 'owin'
    volume(x)

### 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()`.
`x` | Object of class `owin`

### 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.

The function `volume.owin` is identical to `area.owin` except for the argument name. It is a method for the generic function `volume`.

### Value

A numerical value giving the area of the window.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

and Rolf Turner r.turner@auckland.ac.nz

### See Also

`perimeter`, `diameter.owin`, `owin.object`, `as.owin`

### Examples

      w <- unit.square()
      area(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(mas)
          # returns approx area of k-gon

      mas <- as.mask(square(2), eps=0.01)
      X <- raster.x(mas)
      Y <- raster.y(mas)
      mas$m <- ((X - 1)^2 + (Y - 1)^2 <= 1)
      area(mas)
           # returns 3.14 approx

[Package spatstat.geom version 2.3-2 Index]