[R] Centre of gravity of a mountain

[Peter Langfelder]

Weighted mean of x and y coordinates (sorry for the pun :)), that is
something like

n = 21
y = matrix( c(1:n), n, n)
x = matrix( c(1:n), n, n, byrow = TRUE)

# These are the Center of mass coordinates:
xCenter = sum(x * Z)/sum(Z);
yCenter = sum(y * Z)/sum(Z);

If you also need the z coordinate, it simply the mean of the matrix Z.

zCenter = mean(Z)

Peter




On Mon, Nov 8, 2010 at 9:07 AM, Ab Hu <master.rstat at yahoo.com> wrote:
>
> Hi all,
> I have a matrix of a mountain of form 21x21 and values in them are height
> (Z). Using the persp function I can view this mountain in 3D.
> Now, I am trying to find a measure to find the centre of gravity (maybe
> centroid?) of this mountain. Any idea what would be the best way to go?
> --
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