Centroid of a window
Computes the centroid (centre of mass) of a window
- A window
The centroid of the window
w is computed.
The centroid (``centre of mass'')
is the point whose $x$ and $y$ coordinates
are the mean values of the $x$ and $y$ coordinates
of all points in the window.
The calculation uses an exact analytic formula for the case of polygonal windows.
Note that the centroid of a window is not necessarily inside the window. If the window is convex then it does contain its centroid.
- A list with components
x, ygiving the coordinates of the centroid of the window
w <- owin(c(0,1),c(0,1)) centroid.owin(w) # returns 0.5, 0.5 data(demopat) w <- demopat$window # an irregular window plot(w) # plot the window points(centroid.owin(w)) # mark its centroid wapprox <- as.mask(w) # pixel approximation of window points(centroid.owin(wapprox)) # should be indistinguishable <testonly>centroid.owin(w) centroid.owin(wapprox)</testonly>