Hello I am Roger and this is my very first post here.

I wonder if:

I have some surfaces enclosed on sphere.
I know the area, circumference and the mass of centre(I know how far is a mass of center from all the others) for all surfaces.

Is it possible to calculate the coordinates of the circumference-line a) when for every point of every such line there exists differential, b) the differential does not exist for every point?

Say, the surfaces are different countries on earth and I want to calculate the borders by just knowing macro-parameters.

How is calculated the mass of centre of countries (and could I "reverse" the method)?

btw, if my writing is garbled: I'm very sleepy and I watched the smileys all the time.