the center of the world (was Re: Check out O'Reilly's Open Source Convention Highlights)

[markus at kepler.ibp.de]

"Alex Martelli" <aleaxit at yahoo.com> writes:

> Anyway, once I do have such a file, I can presumably find the
> "center of the world" (approximate) -- the one point on the Earth's
> surface that minimizes population-weighted sum of great-circle
> distances to 'population centers'.  Of course I could get different
> centers by choosing different weighing factors (country GNP rather
> than country population, for example).
> 
> Hmmm, if the coordinates were on a plane, finding the weighed
> center would be trivial, but offhand I can't think of how to
> do it on a sphere's surface -- I guess there must be some way
> more suitable than just solving a generalized extremization
> problem -- can anybody suggest one...?

Then find first the weighted average as a point in three-dimensional
space, i.e. as (an approximation to) the center of gravity of the
human population. This will be some point deep in the interior of the
Earth, which you could the project back to the surface.


Markus