| area.owin {spatstat} | R Documentation |
Computes the area of a window
area.owin(w)
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().
|
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 numerical value of the area of the window.
Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner rolf@math.unb.ca http://www.math.unb.ca/~rolf
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