Compasses point to true north

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santaman2000

M.A.B (Mad About Bushcraft)
Jan 15, 2011
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Florida
IIRC magnetic direction is measurable in rock, igneous rock AIUI. The true north/ south axis is something that can be observed not measured. I guess we'll never know what happened prior to humans making and recording the observations of this.
Actually true north/south axis can be measured (or plotted might be a better word) They’re the points where all time zones converge.
 

Janne

Guest
Feb 10, 2016
12,368
2,258
Grand Cayman, Norway, Sweden
Being a Scandihooligan, I have a very small brain.
For me, physical North is where the vertical line on the map points.
Vertical as in the line (usually black) running from top of the paper map as you read it, to the bottom.

A question: If you stand on the spot where true North is, what is the time?
 
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Robson Valley

Full Member
Nov 24, 2014
8,380
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McBride, BC
Many kinds of Northern Hemisphere maps attempt to show something of the contours of the land forms with shading on one side of each mountain/hill.
The sun is in the southern sky for us in the northern hemisphere.
Yet the map shading on the south sides of mountains informs me that the sun is in the northern sky.
Is this cartographic sleight-of-hand of true value? The light on the map coming from "above?"
 

Winnet

Forager
Oct 5, 2011
120
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Aberdeen
You get some beautiful examples of cartography around and the Swiss are the cunning masters of this art. Something to do with having one or two mountains in the country somewhere lol.

G


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Robson Valley

Full Member
Nov 24, 2014
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McBride, BC
Mountains are commonplace here.
I live between some of them.
Less than 3% of British Columbia is flat.
The shading in the maps is quite subtle.
 

Janne

Guest
Feb 10, 2016
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Grand Cayman, Norway, Sweden
I prefer the ‘other’ type of maps. Easier to read. You call them OS maps in UK?
I guess you like best what you are used to!

Edit: looking closely on the Swiss map, I think the closely spaced ‘shading lines’ indicate very steep slopes, so steep that the normal height increase indicating lines would be to close.
Not sure about the height differences between the ‘normal’ lines on this map, it is indicated on it.
It is 5 meters or 10 meters?
The dots could be areas with lots of fallen stones, scree areas, or avalanche paths?
Again, it will say on the map.
There is no 'shading' on that map. every line and marking has a meaning.
The various colours indicate what is growing there.

Maps are great art. Huge amount of work went into them. I had most of my issued maps, but lost them all due to water ingress into the container when we moved.
 
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Tengu

Full Member
Jan 10, 2006
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Wiltshire
Me too, Maps are great art even if you cannot read them.

And all great art tells you a story.

We dont have the shading...thats a relic of the `hairy caterpillar` days.

And you are right, the sun is shining from the north in your map...very funny!
 
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Janne

Guest
Feb 10, 2016
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Grand Cayman, Norway, Sweden
Is not a "shade' but symbols (indication) for a very steep mountain side.

Look closely and you will see that the 'shading' is on the mountain areas facing away from the glaciers. Mostly towards the valley.
The shape of the valley and surrounding mountain faces is created by the Ice age glacier that covered most of Switzerland.

In some areas, the scree looks like 'shading' too. Lots of dots.
 
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Winnet

Forager
Oct 5, 2011
120
27
Aberdeen
They use a lot of cartographic tricks to make a beautiful map from shading to using colours and the way the contours are shown. I was trained in cartography years ago but never managed to get to that standard.

Alas, nowadays I am stuck with creating charts for oil rig moves offshore, basic of the basic and very simple.

G

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baggins

Full Member
Apr 20, 2005
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Coventry (and up trees)
sat here looking at a couple of OS maps, one from the early 90's and one i bought 2 years ago, so revised 2013. In the Map legend, the Magnetic North is estimated at 5 degrees west of grid north in 1996 and 2 degrees in 2013. So, to answer Woody Girls original post, it would be right that now Magnetic North is now the same as grid north, not true north.