Warren wrote: > A notion of median friendly wth L2 distance is this: > a point is a "2D median" if and only if, > for every line thru that point which misses the others, > exactly half the other points are > on each side of it.
Perhaps a better generalization of median to higher dimensions is the Fermat-Weber point, the point that minimizes the sum of the L2 distances from it to each point. (Average can be similarly generalized, minimizing the sum of squared L2 distances.) It always exists (of course) and is unique unless you have an even number of collinear points and the middle two are different. It is also rotationally invariant. -- Rob LeGrand, psephologist [EMAIL PROTECTED] Citizens for Approval Voting http://www.approvalvoting.org/ ____________________________________________________________________________________ Any questions? Get answers on any topic at www.Answers.yahoo.com. Try it now. ---- election-methods mailing list - see http://electorama.com/em for list info
