Continental Pole of Inaccessibility (Posted on 2008-05-14)

	Submitted by Charlie
Rating: 4.5000 (4 votes)
Solution:	(Hide)
If there were only one point on the edge of the sea that was that close, a farther point could be achieved by moving the "pole of inaccessibility" farther away from that point. To be limited to the 2848 km distance, there must be other shores at the same distance, in a direction at least 90° away from that of Tianjin on the Yellow Sea. In fact, if there were only one such other point besides Tianjin, then there'd still be room to go farther, along a line perpendicular to the two nearest points. So there must be a third point also constraining the CPI from being removed from the stated point. A check with an Atlas and some distance-calculating software shows that the other two points are along the Kara Sea in Siberia, and near Calcutta on the Bay of Bengal. They are equally as close to the stated location as the port of Tianjin. As given in http://cuba.ija.csic.es/~danielgc/papers/Garcia-Castellanos,%20Lombardo,%202007,%20SGJ.pdf, from the Scottish Geographical Journal: The location on Earth furthest from the ocean is located in the north-western Chinese province of Xinjiang. Within the uncertainty inherent to the definition of the coastline, two locations are proposed as Pole of Inaccessibility: EPIA1 (44°18'1"N; 81°51'31"E) and EPIA2 (45° 17' 60"N; 88° 8' 24"E). EPIA1 is equidistant 2510+10 km from Gulf of Ob, Gulf of Bengal and the Arabian Sea, and EPIA2 is equidistant 2514+7 km from Gulf of Ob, Gulf of Bengal and Gulf of Bohai (China). EPIA1 and EPIA2 are 435 and 156 km far respectively from the location popularly accepted as the EPIA (Figure 4). The significance for the puzzle, though, is that it is necessary to be equidistant from three points on the coastline--not just one. And those three points must lie on a circle with the radius as the maximal distance to the sea, and they can't be concentrated on just one semicircle, otherwise there'd be room to go in the opposite direction.

	Subject	Author	Date
	Google	brianjn	2008-05-19 00:36:21
	hmm	Eigenray	2008-05-17 03:25:17
	re(3): Somewhat confused	brianjn	2008-05-15 19:56:34
	re(2): Somewhat confused	Charlie	2008-05-15 13:16:14
	re: just asking	Charlie	2008-05-15 13:08:50
	re: Somewhat confused	brianjn	2008-05-15 09:45:57
	Somewhat confused	FrankM	2008-05-15 07:23:07
	From the snippet...	Dej Mar	2008-05-15 03:03:20
	re: Very interesting problem...	brianjn	2008-05-15 02:18:14
	just asking	Ady TZIDON	2008-05-15 01:55:34
	Very interesting problem...	SilverKnight	2008-05-15 01:34:41
	re(2): Farthest point	brianjn	2008-05-15 00:02:27
	re: Farthest point	Charlie	2008-05-14 22:30:34
	Farthest point	brianjn	2008-05-14 20:51:40
	re: Encarta solution	Charlie	2008-05-14 16:14:46
	Encarta solution	FrankM	2008-05-14 13:22:03
	solution (maybe)	Daniel	2008-05-14 12:04:39