Coordinates And Actual Distance

[+ryme-intrinseca]

Hello, not sure how to word this so it will make sense..

 

Let's say I have some sets of co-ordinates:

 

A. N 50deg 57.391, W 002deg 31.191

 

B. N 50deg 57.392, W 002deg 31.191

 

C. N 50deg 56.391, W 002deg 31.191

 

D. N 51deg 57.391, W 002deg 31.191

 

Co-ord's B,C and D are different from A by only 1 digit, but how much distance would this actually be on the ground?

 

Does that make any sense at all?!

[+Milbank]

See if this helps, Markwell

[+MarcoXono]

Simple answer:

 

Latitude (North/South):

One degree difference is about 69 miles.

 

Longitude (East/West):

It depends how far north (or south) you are, as lines of longitude converge at the poles.

At your coordinates (Sherborne, UK), one degree difference is about 43.5 miles.

 

These links may help:

Surface Distance Between Two Points

Longitude Distances

 

For a more comprehensive answer, search for 'Mercator projection' and 'Great circle calculation', and be prepared for some heavy-duty maths!

Edited May 23, 2005 by MarcoXono

[+Hoppingcrow]

Distance between two points on the globe becomes very subjective when you're on one side of a 400' deep ravine and the cache is on the other, especially if the ravine is only 75' wide. Things like 40' cliffs have an amazing capacity for hiding between two 20' contour lines.

[+ryme-intrinseca]

Fantastic, that is the exact info I needed - thanks guys!

[+AtoZ]

My rule of thumb I use for my area is 6feet for every 1000th of a minute. So one minute covers approx. 6000 feet or just over a mile a degree would be 60 times 6000. Looke at the Markwell and you get a good idea of what it should be in your area.

cheers

[+Cardinal Red]

AtoZ has a good rule of thumb, for Latitude (North and South). 6' per 1/1000 of a Minute Latitude is a very close approximation, anywhere on Earth.

 

Longitude is quite a different story. At the Equator Longitude lines are the same 6' per 1/1000 Minute, but they are touching at the Poles. The easy approximation for everything in between correlates to Cosine on a scientific calculator.

 

Equator = 0° Latitude Cosine of 0 = 1.000 6' times 1.000 = 6' Longitude spacing at the Equator

 

At 15° Latitude Cosine of 15 = .9659 6' times .9659 = 5.795' Longitude spacing

 

At 30° Latitude Cosine of 30 = .866 6' times .866 = 5.196' Longitude spacing

 

At 45° Latitude Cosine of 45 = .707 6' times .707 = 4.242' Longitude spacing

 

At 60° Latitude Cosine of 60 = .500 6' times .500 = 3' Longitude spacing

 

At 75° Latitude Cosine of 75 = .2588 6' times .2588 = 1.5528' Longitude spacing

 

North or South Pole = 90° Latitude Cosine of 90 = 0.000 6' times 0.000 = 0' Longitude spacing at the Poles (touching).

 

Had to make center part Bold because the Web Site removed my spaces.

Edited May 23, 2005 by Cardinal Red

[+Yamahammer]

The things you learn on here.