dda
05/12/06 08:07 PM
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I posted the four places according to GE, GM, LL and YM as the default map center.
They all decides that the center of the world is in the center of USA. That the reason why I put it first in the "Unexplained" categorie. You changed the categorie to "Geographic Extremes" and it's a strange choice.
The reason why they choose USA for map center is probably more pragmatic than political. (I hope) It's probably because most of the request are in USA... (Not so sure...)
The question is : Why they don't have the same center ?
As long as I don't have the answer, the categorie is the "unexplained" one.
dda
PS. Idea for them : Why not displaying a moving center of the world ? A real time updated mathematical average of the requests. (I bet it's somewhere in Atlantic ocean)
dda
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romulusnr
05/15/06 09:47 PM
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Fancy this, http://maps.google.co.uk/ centers on Crewe.
http://maps.google.de/ centers halfway between Maibach and Hambach.
http://maps.google.co.jp centers ... somewhere in the water off the coast of... someplace in Japan. (I can't read Japanese.) Ahem... centers in the water about 10 miles west of Kanazawa. (thanks, Ymaps.)
http://maps.google.ca/ centers on the University of Winnipeg. Interesting.
Oh yeah. And http://maps.google.fr centers on La Chapelle-Montlinard.
So. And.
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dda
05/16/06 05:12 AM
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Ok, but why they found different geometrical centers of mass for the same shape of USA ?... They probably forgot or add some islands... Or they chosen a center by guesswork.
dda
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Parabellum
05/16/06 06:40 PM
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The geographic center of the conterminous U.S. (48 states) is near Lebanon, Kansas. The geographic center of the U.S. including Alaska and Hawaii is west of Castle Rock, South Dakota. The geographic center of the North American continent is 6 miles west of Balta, North Dakota . The geographic center of Illinois is Logan, 28 miles northeast of Springfield.
SOURCE:
The World Almanac and Book of Facts 1998. Mahwah, N.J.: World
Almanac Books, 1997.
VGT Moderator
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kjfitz
05/16/06 07:58 PM
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In '86 I drove from NC to Vancouver and back using non-interstate highways. Totally by coincidence I encountered both monuments (the one in Kansas and the one in ND).
kjfitz
Virtual Globetrotting Moderator
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romulusnr
05/17/06 02:35 PM
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Well, there is a page regarding the ND monument of "center of north america" that illustrates just how much controversy there really is as to how to determine "center" of a land mass. In fact the link at http://virtualglobetrotting.com/map/12086/ is one such page: http://www.confluence.org/confluence.php?visitid=11375
When trying to determine geographic center of anything, questions like the following arise:
*Do you include continental shelf?
*Do you include inland waterways?
*Do you subtract inland bodies of water (i.e. lakes)?
*Do you include all islands?
*Do you account for the curvature of the earth? If not, what map projection do you use?
Above all that, the mathematical methods themselves differ. Modern definitions qualify center as the point at which a flat object of the shape of the land mass would be perfectly balanced. Others define it as the point at which the distance to all extents reaches equilibrium. An old definition has it at the midpoint of the rectangle formed by the maximum longitudes and latitudes of the land mass. A much older definition put it at the intersection of lines criscrossing from the four most extreme corners of the land. Etc., etc., etc.
And this controversy is not limited to the US or North America; see http://en.wikipedia.org/wiki/Geographic_center_of_europe
What all this may have to do with the divergent default start points of the various online AJAX maps, I dunno.
As for your map: http://virtualglobetrotting.com/search.php/t/prev/srid/57933/s/0?v=2
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kjfitz
05/17/06 03:26 PM
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Then again, it is all sort of relative isn't it.
http://www.flourish.org/upsidedownmap/diversophy-large.jpg
kjfitz
Virtual Globetrotting Moderator
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dda
05/17/06 05:35 PM
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Nice map, Kjfitz
Idem for the center of France according to the "Quid 2003" 9 places clamed they're the center of France.
St-Amand-Montrond.
Bruères-Allichamps.
Vesdun : à La Courcière à 8 km de Saulzais, d'après Pierre Vermond.
Entre les hameaux de « Frappon » et « la Presle » d'après le général Gérin.
A 300 m du point Gérin d'après Georges Dumont.
Près du hameau de Mondan d'après Puisségur.
Chazemais : d'après Georges Dumont en 1966. Même procédé mais en ajoutant la Corse.
A 550 m au nord - nord-ouest de Villevendret.
Nassigny : selon l'IGN. Corse comprise.
http://www.quid.fr/2003/30_01.htm
dda
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