# Longitudes and Latitudes

#### JonB

Associate
Hi There,

I'm playing with longitudes and latitudes and wondering if you maths folk know of a standard formula that would give you the distance between one long and lat and another long and lat, as the crow flies?

Thanks

Man of Honour

#### JonB

Associate
OP
Do you mean, will the shape of the earth's curvature need to be taken into account?

#### JohnnyG

Man of Honour
Nope, it was a rubbish joke

Permabanned

Soldato

#### Ricochet J

Soldato
Isn't it:

AC = sqrt ((A-B)sq+ (B-C)sq)

Where sqrt stands for square root and sq stands for squared.

#### JonB

Associate
OP
JohnnyG said:
Nope, it was a rubbish joke

Damn you

I'm not in the quickest of moods, I wasn't sure what laden meant so I google defined it.

Suspended
Ricochet J said:
Isn't it:

AC = sqrt ((A-B)sq+ (B-C)sq)

Where sqrt stands for square root and sq stands for squared.
No, that only works for flat surfaces. The surface of the earth is very definitely curved. The page Haircut linked to has the correct formula for distances on the surface of a sphere.

#### Haircut

Soldato
Ricochet J said:
Isn't it:

AC = sqrt ((A-B)sq+ (B-C)sq)

Where sqrt stands for square root and sq stands for squared.
The Earth is a non-Euclidean surface though so you can't do that.

#### KaHn

Soldato
Surely just use the length of an arc

L=(theta)*r

Where r = radius of the earth and the (theta is the angle between the longs and lats in radians.

KaHn

Suspended
KaHn said:
Surely just use the length of an arc

L=(theta)*r

Where r = radius of the earth and the (theta is the angle between the longs and lats in radians.

KaHn
Works if you happen to know the angle between the two coordinates you're interested. Unfortunately, unless they're at the same latitude or longitude then you have to do some extra maths first. Much easier just to use the analogue of Pythagoras' theorem for spherical surfaces.

#### KaHn

Soldato
Works if you happen to know the angle between the two coordinates you're interested. Unfortunately, unless they're at the same latitude or longitude then you have to do some extra maths first. Much easier just to use the analogue of Pythagoras' theorem for spherical surfaces.

Yeah sorry, i didn't read fully and just thought he meant distances in a straight line, say lat 20 to lat 40 distance.

KaHn

#### Dist

Soldato
Azagoth said:
African or European?

A european one cant carry a coconut, and african ones dont migrate

Associate
OP
Haircut said:

Cheers