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Re: Re: "Re: Centroid of the Earth's Surface"

• To: mathgroup at smc.vnet.net
• Subject: [mg30290] Re: [mg30278] Re: [mg30255] "Re: Centroid of the Earth's Surface"
• From: Ken Levasseur <Kenneth_Levasseur at uml.edu>
• Date: Sun, 5 Aug 2001 16:18:34 -0400 (EDT)
• References: <200108050002.UAA20854@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Suppose that all of the dry land on earth consisted of two disjoint, square islands of
identical area. Where would the centroid be located?

Ken Levasseur
Math. Sciences
UMass Lowell

Jonathan Rockmann wrote:

>
> Very nicely put Zakir.  I think this was just a simple case of knowing what one means.
>
> Jon
> mtheory at msn.com
>
>
> ----- Original Message -----
> From: seidovzf at yahoo.com
To: mathgroup at smc.vnet.net
> To: mathgroup at smc.vnet.net
> Subject: [mg30290] [mg30278] [mg30255] "Re: Centroid of the Earth's Surface"
>
> 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: [mg30290] [mg30278] [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: [mg30290] [mg30278] [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
> %%%%%%%%%%%%%%%%%%%%%

• References:
  • Re: "Re: Centroid of the Earth's Surface"
    • From: "Jonathan Rockmann" <MTheory@msn.com>