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MathGroup Archive 2001

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"Re: Centroid of the Earth's Surface"

  • To: mathgroup at smc.vnet.net
  • Subject: [mg30255] "Re: Centroid of the Earth's Surface"
  • From: seidovzf at yahoo.com (Zakir F. Seidov)
  • Date: Sat, 4 Aug 2001 01:14:23 -0400 (EDT)
  • References: <9kb0v3$c7d$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

keywords:
centroid/ dry land of Earth/ Mathematica 
 
Hi,
I'm not sure, but it seems to me that dry land 
(as well as sea/oceans) on the Earth surface 
can perfectly have centroid or any other center - 
depending on assumptions. 
=========================

E.g. Saudia Aravia itself has a certain centroid, 
and  it's  easily can be found, 
if you draw map of S.A. on (a hard) paper, 
cut it by contour, 
hang it two times in two positions of nail, 
and two crossing  "verticals"'ll give centroid. This is trivial.

The problem arises for larger territories 
when the map is NOT flat. 
If the centroid is stiil defined as center of gravity,
then MATHEMATICA is OK to calculate centroid of any 3D surface,
but centroid of DRY LAND SURFACE should be somewhere deep inside, 
close to Earth's center -
to bitter dissapointment of any patriot of his/her homeland.

Interestingly enough, semi-official CENTER of Euro-Asia is
 somewhere in Ural mountains, in this case center being defined 
as point of maximal (or minimal?)  mean distance from boundaries of
Euro-Asian continent.

And it's quite may be that at some assumptions
Saudia Arabia posseses a some center of dry land surface -
don't give up, Muhammad! ;-)

Zakir 
 
%%%%%%%%%%%%%%%%%%%
Subject: [mg30255]      Re: Centroid of the Earth's Surface
Author:       Henry Lamb <hlamb at cg.NRCan.gc.ca>
Organization: Steven M. Christensen and Associates, Inc and
MathTensor, Inc.


I hate to disappoint you, but it can't be done. That's because the 
earth's surface has no centroid. Only bounded surfaces (or volumes)
have 
centroids. If Saudi Arabia appears to be at the centre of the earth, 
that's due to the map you're using. Buy a globe.

Henry Lamb


%%%%%%%%%%%%%%%%%%%
Subject: [mg30255]      Centroid of the Earth's Surface
Author:       Muhammad Hutasuhut <mhutasuhut at sympatico.ca>
Organization: Steven M. Christensen and Associates, Inc and
MathTensor, Inc.


Saudi Arabia appears to be at the center (or centroid) of the earth's 
dry land. I would like to prove it by using Mathematica. I need
guidance 
on how to do it!

Regards
M. J. Hutasuhut
%%%%%%%%%%%%%%%%%%%%%



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