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From: nolan@portia.Stanford.EDU (Patrick Nolan)
Newsgroups: sci.math,comp.graphics
Subject: Re: Barycentric coordinates
Summary: It's astronomy?
Keywords: Barycentric,coordinates
Message-ID: <5902@portia.Stanford.EDU>
Date: 16 Oct 89 23:23:36 GMT
References: <346@texhrc.UUCP>
Sender: Patrick Nolan <nolan@Portia.stanford.edu>
Reply-To: nolan@Portia.Stanford.EDU (Patrick Nolan)
Followup-To: sci.math
Organization: Stanford University
Lines: 27

In article <346@texhrc.UUCP> bls@texhrc.UUCP (Brian L. Sumner) writes:
>I would appreciate some references to - or a quick discussion of
>Barycentric coordinates.  I think I want to use them to answer the
>the following problems:
>
>1) Given a set of n points (in 2 or 3 space),
>   decide whether an arbitrary given point is interior to the convex hull of
>   the n points.
>
>2) Given a set of n points, find which edge of their convex hull is closest
>   to an arbitrary given point.
>
Barycentric coordinates are used in astronomy in the study of pulsars.
The Barycenter is a fancy term for the center of mass of the Solar
system.  When the vector to the pulsar is expressed in barycentric
coordinates instead of geocentric coordinates, then you don't have to
make corrections for the Doppler shift caused by the motion of the
Earth.

I suppose there might be a non-astronomical version of barycentric
coordinates too.  If so, I would like to hear about it.

-- 
=======================================================================
 Patrick Nolan                    Bitnet: PLN@SLACVM 
 W. W. Hansen Laboratories        Internet: nolan@meggie.stanford.edu
 Stanford University                        nolan@portia.stanford.edu