[R] Center of Closed Contour

[Charles M. Fleming]

I am searching for a utility in R which will determine the mean location of
a closed contour and eventually record the location in an ASCII file. By 
means of the contour utility in R, I am able to produce an image of a contour,
but I am seeking a procedure which will produce the coordinates of the
center of mass of the contour. From my actual set of data, the contour
utility will produce several hundered closed non-intersecting and
non-concentric contours like a lattice of disks. I want the location of
those disks via a program. Is there any package in R which will lend
itself to this problem?

Thank you,

Charles Fleming