Brief Thoughts On Maps

Cutaway

LE
Kit Reviewer
On magnets like poles repel - opposites attract
Ergo as the North pole of a magnet is pointing to the North pole then North pole is in fact a magnetic south
Or the North Pole is a magnetic north and all compasses have the magnetic south labelled as what points to north.
 
Or the North Pole is a magnetic north and all compasses have the magnetic south labelled as what points to north.
Indeed

But I think we can all agree that what is identified as magnetic north on a magnet points to what's identified as magnetic north on a map which suggests someone didnt think it through.
 
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The Earth is effectively a dipole magnet. Other planets have more than two poles, usually giant planets (I think Jupiter is an octopole).

The field lines of a dipole magnet flow from N to S. So the magnetosphere of the planet tells us which pole is "North" in magnetic terms (the south pole) which is not the same as in navigational terms. It doesn't matter what you call them in human usage. Christ knows how it works on a multipole planet.

I just typed that and I am not sure it makes any sense to me.
 
The Earth is effectively a dipole magnet. Other planets have more than two poles, usually giant planets (I think Jupiter is an octopole).

The field lines of a dipole magnet flow from N to S. So the magnetosphere of the planet tells us which pole is "North" in magnetic terms (the south pole) which is not the same as in navigational terms. It doesn't matter what you call them in human usage. Christ knows how it works on a multipole planet.

I just typed that and I am not sure it makes any sense to me.
Every day is a learning day .
 
The Earth is effectively a dipole magnet. Other planets have more than two poles, usually giant planets (I think Jupiter is an octopole).

Christ knows how it works on a multipole planet.
Any poles a goal

why yes, that is indeed my ride home

Edit
On a more sensible note from a nav point of view - I suppose its a case of knowing which north youre aligned to
or rather not aligned to but trying to be)

Bit like Decca you could calculate youre position to within a gnats cock within each lane but you had to know which of the 14nm ? lane blocks you were in to plot your position
 
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Indeed

But I think we can all agree that what is identified as magnetic north on a magnet points to what's identified as magnetic north on a map which suggests someone didnt think it through.
Isn't the proper pedantic name "the north-seeking point" of the needle?
 
The Earth is effectively a dipole magnet. Other planets have more than two poles, usually giant planets (I think Jupiter is an octopole).

The field lines of a dipole magnet flow from N to S. So the magnetosphere of the planet tells us which pole is "North" in magnetic terms (the south pole) which is not the same as in navigational terms. It doesn't matter what you call them in human usage. Christ knows how it works on a multipole planet.

I just typed that and I am not sure it makes any sense to me.
If you really want to get metaphysical, 'North' and 'South' are human constructs - the virtual electrons that make up the magnetic field don't really care (or in any real sense, actually exist) which way is 'North', nor that their charge is 'negative'.

Also, up and down are human constructs too. We're just quite lucky that the magnetic poles are pretty close to the axis on which our planet rotates (because of the dynamo effect of our inner and outer cores).
 
North was pretty much irrelevant to early mapmakers. Often they were aligned in whatever took the cartographers fancy: Jerusalem at the centre; aligned to the south; aligned to the east etc.

In a sense it didn't really matter as long as everybody was using the same terms of reference. The maps were pretty much useless for navigation anyway. Many early maps (like the Mappa Mundi) were not really designed for navigation purposes but more as an exposition of power, religion, history etc.

I have stated it here before but I really hate those old maps (wouldn't mind finding a few though).

Probably the first vaguely useful one was made by the Turk Piri Reis in the early 16th century. It was reasonably accurate (at least in the Med and the eastern Atlantic) but like most maps of the time was also full of rubbish (such as mystical islands like Atlantis. And possibly Japan). I can't help but think that mariners must have had their own real maps or mental maps to help them get from A to B.

Anyone having issues with grasping that the North Pole is actually the southern magnetic dipole is probably going to freak out if they are around for the next geomagnetic reversal (actually long overdue). Then the North Pole, which is actually the South Pole will become the South Pole which will become the North Pole which it was previously before the actual South Pole became the new North Pole.

Or something.
 
If you really want to get metaphysical, 'North' and 'South' are human constructs - the virtual electrons that make up the magnetic field don't really care (or in any real sense, actually exist) which way is 'North', nor that their charge is 'negative'.

Also, up and down are human constructs too. We're just quite lucky that the magnetic poles are pretty close to the axis on which our planet rotates (because of the dynamo effect of our inner and outer cores).
Absolutely.

The entire universe is what we decide it is.

Time just is: it couldn't care less if we measure it in seconds, hours, days etc. That's just something we do and they are mostly inaccurate anyway (leap years, leap seconds etc).

The Sun couldn't care less if it is 93 million miles away or 25 zargons. It doesn't GAF.

We are metre scales organisms that just overlay an understandable and graspable set of measurements on the cosmos around us.
 
Absolutely.

The entire universe is what we decide it is.

Time just is: it couldn't care less if we measure it in seconds, hours, days etc. That's just something we do and they are mostly inaccurate anyway (leap years, leap seconds etc).

The Sun couldn't care less if it is 93 million miles away or 25 zargons. It doesn't GAF.

We are metre scales organisms that just overlay an understandable and graspable set of measurements on the cosmos around us.
Hawking (and Mlodinow) cover this well in 'A Grand Design'. Well worth a read in order to remind us of our limitations in only being able to understand what we can perceive as humans.
 

Cutaway

LE
Kit Reviewer
The Earth is effectively a dipole magnet. Other planets have more than two poles, usually giant planets (I think Jupiter is an octopole).

The field lines of a dipole magnet flow from N to S. So the magnetosphere of the planet tells us which pole is "North" in magnetic terms (the south pole) which is not the same as in navigational terms. It doesn't matter what you call them in human usage. Christ knows how it works on a multipole planet.

I just typed that and I am not sure it makes any sense to me.
I knew offrs got their nav expertise from another planet.
 
but like most maps of the time was also full of rubbish (such as mystical islands like Atlantis. And possibly Japan).
I dont know how to break it to you gently but Japans real, admittadly its lacking in the oft depicted 200M tall dinosaur type thing traipsing through the villages - but the lands themselves are confirmed as existing
 

TamH70

MIA
I knew offrs got their nav expertise from another planet.
I had one of those. Ended up being the C.O. of the Regiment I was part of. His tally included nearly drowning me and the Rover I was in about three miles as the crow flies from my house on Ex. Then he put the whole Regiment in the middle of a forest that the infantry types that were teaching us woodland skills said was utterly the wrong kind as the visibility was about five feet in any direction so no-one could see anything let alone field signals, and the midges were so big that one of the smaller tykes in my section got lifted away for later eating.

I'd still rate him as a good officer but still shudder to this day about him getting hold of a map or a G.P.S.
 

TamH70

MIA
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