If a person stands on the north, or south pole. How do they determine which way is east/west?

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    Welcome to gis.SE. Its an interesting question, but difficult to provide a useful answer without some kind of context. Are you just asking out of interest, or is there some background reason for this question? – BradHards May 15 '13 at 18:50

No matter where you are on earth direction is determined based on one other point, which is the point opposite it. When you're at the North Pole your opposite point (antipode) is the South Pole.

As soon as you move away from the exact North Pole this changes - on the earth we determine east/west (perpendicular to the North/South Poles) based on the rotation of the earth around its' axis.

This is the theory at least - in practice this can be a bit trickier since the earth is not a perfect sphere.

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    Concerning the first sentence: there are still 360 degrees of possible directions, not one direction! The issue is that "South" no longer designates a unique direction. Instead you could use (say) longitude to designate various directions, such as "that polar bear is one kilometer away along the -72 degree meridian." It strikes me that this direction would be exceedingly relevant if the polar bear were any nearer! Re the last sentence: because all ellipsoidal models of the Earth are rotationally symmetric, the issues don't change and aren't any more or less "tricky." – whuber May 15 '13 at 18:02
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    Perhaps 'bearing' should be used instead of 'direction'. I merely meant that in terms of North/East/South/West, the only bearing you can travel from the North Pole is South. – Radar May 15 '13 at 18:05
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    That's a strange interpretation of "direction." Perhaps if you more specifically stated "cardinal direction" your point would be clearer. But you're going to tie yourself in knots trying to explain it this way. It comes down to the fact that all the usual cardinal directions (including South) are undefined at the North Pole: but there is still an entire circle of directions (and bearings) in which one can look. – whuber May 15 '13 at 18:09
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    Fair enough. As you say, the cardinal directions are undefined and therefore the terminology needed for an answer differs - it's no longer appropriate to use the word 'direction' or 'way'. Therefore, in answer to the original question, east is not defined while at the North Pole. The concept of east/west doesn't apply. – Radar May 15 '13 at 18:48

If we consider North Pole as infinitesimally small point then when you stand such that rotational axis passes through your body center, and start rotating counter-clockwise then parts of your body outside the axis would be moving east.

  • Why are some parts moving east (as opposed to west?, or down, or some other direction)? – BradHards May 15 '13 at 19:36
  • It is basically the equivalent of taking a few steps in any direction. Then when you turn left by 90 degrees you would be making circles around the pole in eastward direction – Tomislav Muic May 15 '13 at 19:39
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    There is also a famous riddle about this: A hunter pitched her tent and then hiked straight south for five miles; she then turned and hiked five miles due east. Finally she turned again and hiked five miles straight north where she saw a bear ripping apart her tent. What color was the bear? – Tomislav Muic May 15 '13 at 19:47

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