Three Norths

Open up a paper sheet map and along one edge you should find a key to all the symbols that have been used. 

Somewhere with those you’ll perhaps find a diagram like this:

So which way is north?

The parallel lines on the map point to what is called grid north, but that is not quite the same direction as the north pole, because remember the longitude lines don’t run parallel but the grid lines do.  Maps for places down the centre of Britain have grid north closest to true north, while places in the east and west have the biggest difference between the two norths.

But there is a third north point mentioned – magnetic north.  Not only does this one differ from both of the other north points, it also moves!  The map should tell you the position of magnetic north, in relation to the grid, on the date that the map was printed.  It should also tell you about its likely change over coming years.  And why do we need to know?  Well if you are using your map with a compass, the compass points to the magnetic north, not the grid north, so you need to make a correction to avoid heading off in slightly the wrong direction, which could soon get you lost on a foggy hilltop.

I’m not going to attempt to explain in a blog post how to use a compass with a map.  It is much easier to see it done in a video.  Mountaineering Ireland have a very clear explanation here.