Any STW map geeks n...
 

  You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more

Any STW map geeks near Swanage?

13 Posts
9 Users
0 Reactions
137 Views
Posts: 43345
Full Member
Topic starter
 

https://twitter.com/OrdnanceSurvey/status/1587745179955503104?t=282wEiRP2ga-D6UH8FS0Tw&s=19

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


 
Posted : 02/11/2022 11:16 am
Posts: 28475
Free Member
 

Cool. Is this why STW Charlie had to leave?


 
Posted : 02/11/2022 11:25 am
 IHN
Posts: 19694
Full Member
 

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


 
Posted : 02/11/2022 11:29 am
Posts: 28475
Free Member
 

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.


 
Posted : 02/11/2022 11:34 am
Posts: 3223
Free Member
 

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!


 
Posted : 02/11/2022 11:37 am
 IHN
Posts: 19694
Full Member
 

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...


 
Posted : 02/11/2022 11:39 am
Posts: 44146
Full Member
 

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


 
Posted : 02/11/2022 11:40 am
Posts: 28475
Free Member
 

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.


 
Posted : 02/11/2022 11:40 am
Posts: 92
Full Member
 

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

I need a new ryhme now.


 
Posted : 02/11/2022 12:05 pm
Posts: 7656
Full Member
 

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


 
Posted : 02/11/2022 12:14 pm
Posts: 3961
Full Member
 

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


 
Posted : 02/11/2022 12:17 pm
Posts: 92
Full Member
 

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.


 
Posted : 02/11/2022 12:21 pm
 IHN
Posts: 19694
Full Member
 

^ this needs more appreciation. Well done sir.


 
Posted : 02/11/2022 1:47 pm
Posts: 1626
Full Member
 

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


 
Posted : 02/11/2022 5:34 pm

6 DAYS LEFT
We are currently at 95% of our target!