Any STW map geeks near Swanage?

Our calculations have discovered the three 'norths' will combine for the first time in history this week?

True north, magnetic north and grid north will combine at a single point – starting at Langton Matravers, a village just west of Swanage #3Norths pic.twitter.com/suMMVfTEdT

— Ordnance Survey (@OrdnanceSurvey) November 2, 2022

I’d been aware of the convergence for a while. Strange to see it happening.

Cool. Is this why STW Charlie had to leave?

True north, magnetic north and grid north will combine at a single point – starting at Langton Matravers, a village just west of Swanage

Eh? But that’s quite a long way ‘south’ of the pole, innit? I’s confuzzled

This explains it:

https://www.bbc.co.uk/news/uk-england-dorset-63475943

Basically the magnetic ‘north pole’ doesn’t stay in the same place. Depending on your position, for very accurate navigation you have to allow for this difference when using a compass. So there is a ‘grid north’ line which stays the same, and a ‘magnetic north’ line from pole to pole which changes. Which are having a rare convergence in the epicentre of evil that is Dorset.

Really coincidently I was doing an orienteering event on Sunday. Its been years since I’ve had to use a map and compass, so looked up what the deviation was for Grid to Mag, remembering it was about 7deg when I was younger. Was surprised to read I needed to do nothing!

Aaaaaah, so it’s the OS lines of grid/true/magnetic north that have, er, aligned, not the actual points of grid/true/magnetic north. That makes more sense…

30 years ago I was in Northern Norway. Magnetic and true north were about 40 degrees apart. Highly confusing

Cool. Is this why STW Charlie had to leave?

This is getting weird now. It’s chasing him!

According to the OS, the converged line will pass through nearby Poole by Christmas, before moving reaching Hebden Bridge in Yorkshire in August 2024.

Mag to Grid, get rid: Grid to Mag add.

I need a new ryhme now.

Mag to grid at Swanage no big?
Looking at some of the older maps I have its moved quite a bit.

The epic Square and Compass pub is in Worth Matravers, a stones throw away. Makes you think.

Swanage to Fraserborough, I suppose
No need to move the compass rose.
If either side this line is used
To add or take I’ll remain confused.

^ this needs more appreciation. Well done sir.

The location of the best bit of singletrack on the Purbecks, from St Aldhams head to Windspit caves.