What is standard North.

[Albert T Smith 10]

What is the difference between: Grid North, Magnetic North, and Geographical North and do route finders using satellite navigational technology use a Astronaut North?

[scoobz 10]

What is the difference between: Grid North, Magnetic North, and Geographical North and do route finders using satellite navigational technology use a Astronaut North?

 

Bit too technical for this group Albert I`n afraid , personally I use an A-Z when I`m walking, or if hard-pressed an Ordinance Survey, but then I don`t understand it

[JoeP 11]

AFAIK.....

 

Magnetic North is 'compass north' and is a reference to the Earth's magnetic pole. The 'geographical North' refers to the northern axis of the planet - this doesn't coincide with teh magnetic North because the fluid nature of the interior of the Earth causes the Magnetic North pole to 'precess' - or wander - around the high lattitudes of the Northern Hemisphere. This is where the variation between Magnetic and True North comes in when you take a bearing using a compass.

 

GPSs and Sat Navs rely on timing radio signals from a group of satellites in orbit. They determine absolute position using trigonometry.

[JoeP 11]

Yup - I've got a lay-interest in the magnetic field of the Earth because as I'm a radio amateur it's relevant to the propagation of our radio signals.

 

Interesting stuff!

 

There is the alternative view that the Lizard People who live inside the Earth cause precession by moving their HIfi loudspeakers around down there, but this theory hasn't really caught on.

[purdyamos 10]

Technically, according to Prof Hide's web page, the fields are "generated by magnetohydrodynamic self-exciting dynamo action".

 

I like the sound of self-exciting dynamo action, though as yet I haven't come across any on an SF walk, more's the pity.

[Albert T Smith 10]

AFAIK.....

 

Magnetic North is 'compass north' and is a reference to the Earth's magnetic pole. The 'geographical North' refers to the northern axis of the planet - this doesn't coincide with teh magnetic North because the fluid nature of the interior of the Earth causes the Magnetic North pole to 'precess' - or wander - around the high lattitudes of the Northern Hemisphere. This is where the variation between Magnetic and True North comes in when you take a bearing using a compass.

 

GPSs and Sat Navs rely on timing radio signals from a group of satellites in orbit. They determine absolute position using trigonometry.

 

Can the GPSs and Sat Navs location longditude and latitude readings be converted by a maths formula to give a standard Grid Ref?

Or can a 'Brain Box' belong to the Forum come up with one?

[altus 540]

Can the GPSs and Sat Navs location longditude and latitude readings be converted by a maths formula to give a standard Grid Ref?

Yes. There are a number of web pages that do online conversions - including one at the Ordnance Survey.

Or can a 'Brain Box' belong to the Forum come up with one?

The maths is very complex. There's a whole section of the OS site devoted to coordinate systems and transformations between them. Quite interesting in a geeky sort of way.

[Albert T Smith 10]

altus - I've frequently wanted to convert the long & Lat co-ordinates given by Google 'Earth'. You have provided the answer. Thank you for your help.

[Bourne 10]

When using a map and compass you have to add/subtract for the difference in grid/magnetic north.

 

On the OS Explorer maps of the peak its about 3-4 degrees.

 

A GPS device can usually be configured with your own choice of heading.

 

B