Your bits of totally useless geographical trivia please...

[flymo]

The Russian land border with North Korea extends for about 11 miles, roughly the distance from Newcastle to Sunderland.

 

[flymo]

If you were to fly directly, the shortest straight line between London Heathrow airport and Auckland airport in New Zealand, around 11,400 miles, only around 1,300 miles would be over land and the only major land masses you'd fly over would be Norway and Russia.

 

[Calthrop]

The Russian land border with North Korea extends for about 11 miles, roughly the distance from Newcastle to Sunderland.

Another bit of border-type nuttiness: China and Afghanistan share a very short mutual border (some 20 / 30 km) -- at the easternmost end of the odd narrow sticking-out-eastwards bit at the north-eastern extremity of Afghanistan. At the present time, this border is closed.

If you were to get special permission to cross the border; you’d be confronted with the world’s greatest time-zone difference -- three and a half hours.

 

[341o2]

Yet Dorset, Cornwall and no doubt plenty of others have none.

Does Wales have any motorways apart from the M4?

Dorset also does not have any branch lines, the last to Bridport closing in the mid 70's

 

[341o2]

The Bristol Channel has the second highest tidal range in the world, at 15 metres. Spring tides can be as high as 55ft.

And as a result, the Severn bore

 

[IanD]

Does Wales have any motorways apart from the M4?

M48 and A48(M)

 

[me123]

There's also the "secret" Colwyn Bay "motorway" on the A55 - it's subject to the same restrictions as a motorway but actually isn't one. Because it's a special road (like the Motorways in Scotland), NSL does not apply so you'll see 70mph (and in the middle 50mph) signs instead.

 

[Dai Corner]

Lewis and Harris is one Island, not two as the name might suggest, and the third largest of the British Isles

 

[najaB]

Lewis and Harris is one Island, not two as the name might suggest, and the third largest of the British Isles

And the Black Isle isn't an island.

 

[Shimbleshanks]

You can find the City of London symbol (red cross on a white shield) up to 20 miles from central London. It manages several commons in places such as Ashtead (near Epsom), Farthing Down (near Coulsdon) or Spring Park (Bromley).

 

[Bromley boy]

Ordnance Survey election maps seems to show otherwise...

Yep, on that basis, perhaps it's more accurate to say Crystal Palace parade, as a whole, is the point of convergence...

It's a bit of local folklore that the point of convergence is the triangle itself... Seemingly inaccurate!

 

[Bromley boy]

All road signs giving distances to London have Charing Cross as their datum of reference.

 

[Bromley boy]

If you were to fly directly, the shortest straight line between London Heathrow airport and Auckland airport in New Zealand, around 11,400 miles, only around 1,300 miles would be over land and the only major land masses you'd fly over would be Norway and Russia.

At the risk of being accused of severe pedantry, I'll observe that the shortest distance between those two points, as with any two points on earth, will be a great circle, rather than a straight line.

 

[A Challenge]

Ordnance Survey election maps seems to show otherwise...

Election boundaries aren't always the same as district boundaries.

Has someone already done OS grid square SE8322. The dullest emptiest of all the grid squares.

NY050690 is apparently more empty!

Does Wales have any motorways apart from the M4?

Dorset also does not have any branch lines, the last to Bridport closing in the mid 70's

Yes, but the A48(M) is the only completely in Wales. Also, what is a branch line, not the Weymouth Quay branch then?

You can find the City of London symbol (red cross on a white shield) up to 20 miles from central London. It manages several commons in places such as Ashtead (near Epsom), Farthing Down (near Coulsdon) or Spring Park (Bromley).

And Epping Forest.

All road signs giving distances to London have Charing Cross as their datum of reference.

I thought that was only the old mileposts?

 

[najaB]

At the risk of being accused of severe pedantry, I'll observe that the shortest distance between those two points, as with any two points on earth, will be a great circle, rather than a straight line.

A great circle is a straight line along the surface of the globe, it's only a curve on a map.

 

[DaleCooper]

A great circle is a straight line along the surface of the globe, it's only a curve on a map.

It's curved in three dimensions. Unless you're a flat earther.

 

[najaB]

It's curved in three dimensions. Unless you're a flat earther.

Hence 'along the surface' - if you were an ant following the line you would never know that it curves in three-dimensional space.

 

[DaleCooper]

Hence 'along the surface' - if you were an ant following the line you would never know that it curves in three-dimensional space.

What an ant thinks doesn't change the fact that the Earth's surface is curved therefore any line drawn on it is also curved. The clue is in the name "great CIRCLE".

 

[najaB]

What an ant thinks doesn't change the fact that the Earth's surface is curved therefore any line drawn on it is also curved. The clue is in the name "great CIRCLE".

Yes, it's curved in three-dimensional space. However, in two-dimensional space (which the surface of the Earth is at human scale) if it were possible to walk on water, etc. you would turn neither left nor right when following a great circle route.

I'm sure there's a word that could be used to describe a line that can be followed without a change of heading...

 

[Castle Cary]

I sympathise with the guy that thought Wisbech was a seaside resort. As a small schoolboy in East Devon, but home being in Somerset, I got full marks for naming 'three major ports' as London, Southampton and Langport. Oh that GCSEs had been that easy.

 

[Calthrop]

Shades of the old tale of the schoolkid asked to name three major British industrial cities. Kid came up with "Birmingham, Nottingham, and Chewing Gum".

 

[Bromley boy]

Yes, it's curved in three-dimensional space. However, in two-dimensional space (which the surface of the Earth is at human scale) if it were possible to walk on water, etc. you would turn neither left nor right when following a great circle route.

I'm sure there's a word that could be used to describe a line that can be followed without a change of heading...

No, but if you were following a great circle arc, you would be following the curvature of the earth. If you were following a straight line you would end up in space as the earth curved away beneath your course!

The shortest distance between two points over the surface of a sphere, or an approximate sphere in the case of the earth, is a non-straight great circle. Not a straight line.

 

[najaB]

The shortest distance between two points over the surface of a sphere, or an approximate sphere in the case of the earth, is a non-straight great circle. Not a straight line.

I love a good pedantic argument...

By what amount does your heading change while following a great circle?

 

[A Challenge]

A great circle is a straight line along the surface of the globe, it's only a curve on a map.

And vice versa?

 

[Bromley boy]

I love a good pedantic argument...

By what amount does your heading change while following a great circle?

Me too!

Heading changes constantly while following a great circle arc.

A course following a fixed heading would be a rhumb line (crossing all meridians of longitude at the same angle). However this is not the shortest distance between two points.

Of course neither of these are "straight lines" since both are crossing the surface of the (curved) globe!

 

[DaleCooper]

I love a good pedantic argument...

By what amount does your heading change while following a great circle?

Irrelevant, it may not change in an arbitrary XY plane but it certainly does along the corresponding Z axis.

 

[DaleCooper]

I love a good pedantic argument...

Is it pedantic to say a circle is not a straight line? No, it's a statement of fact.

 

[Bromley boy]

Is it pedantic to say a circle is not a straight line? No, it's a statement of fact.

I suppose someone arguing a circle is a straight line makes a change from arguing black is white, as often happens on this forum

 

[najaB]

Me too!

Heading changes constantly while following a great circle arc.

Argh... terminology and frames of reference - the cause of many a great argument.

I didn't mean compass heading (which you correctly point out will change for any great circle other than the equator) but rather rotation around the Z (up/down) axis of the boat/plane/whatever.

So, let me rephrase the question: by how much do you rotate in yaw while following a great circle route?

 

[Howardh]

Three ways of measuring A to B!