- #1

Kel1980

- 5

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Hello,

I'm not a student, I'm just trying to figure out how to calculate coordinates on a globe, and I would like to ask for some help.

Let's say I have POINT A on the globe with the following coordinates:

Latitude 45° 27' 50.95" N

Longitude 9° 11' 23.98" E

Also I have POINT B which is the Antipode:

Latitude 45° 27' 50.95" S

Longitude 170° 48' 36.02" W

Given we are on a sphere (globe), from Point A to Point B for example I can draw 360

- and the distance

- and the distance

Now let's say I have POINT C with the following coordinates:

Latitude 45° 26' 48.53" N

Longitude 9° 1' 58.11" E

Given these information,

START IN POINT A

ARRIVE IN POINT B

COME BACK IN POINT A

My problem is to find the formula to calculate the coordinates of the 2 Points which are half-way (90°) from Point A to Point B.

Let's call these 2 Points as M and N:

START in POINT A

GOES THROUGH POINT C

ARRIVE IN POINT B

COME BACK IN POINT A

On a - plain surface - i would have used the simple proportion of triangles to calculate them, but given is a sphere I don't know the formula to be applied.

I did some online search but I find a kind of difficult to figure it out.

I have been out of school from 15 years now, so I would like to ask if somebody can help me.

I hope my explanation is clear, thanks a lot if you can help!

Cheers

I'm not a student, I'm just trying to figure out how to calculate coordinates on a globe, and I would like to ask for some help.

Let's say I have POINT A on the globe with the following coordinates:

**POINT A**Latitude 45° 27' 50.95" N

Longitude 9° 11' 23.98" E

Also I have POINT B which is the Antipode:

**POINT B**Latitude 45° 27' 50.95" S

Longitude 170° 48' 36.02" W

Given we are on a sphere (globe), from Point A to Point B for example I can draw 360

**great circles**, one for each single degree of the sphere:- and the distance

__to go from Point A to Point B__is 180° (first semi-circle)- and the distance

__to go back from Point B to Point A__is also 180° (second semi-circle)Now let's say I have POINT C with the following coordinates:

**POINT C**Latitude 45° 26' 48.53" N

Longitude 9° 1' 58.11" E

Given these information,

**THERE IS ONLY ONE GREAT CIRCLE**which:START IN POINT A

__GOES THROUGH POINT C__ARRIVE IN POINT B

*(completing the first semi-circle of 180°)*COME BACK IN POINT A

*(completing the second semi-circle of 180°)*My problem is to find the formula to calculate the coordinates of the 2 Points which are half-way (90°) from Point A to Point B.

Let's call these 2 Points as M and N:

START in POINT A

GOES THROUGH POINT C

**PASS THROUGH POINT M***(at 90°)*ARRIVE IN POINT B

*(completing the first semi-circle of 180°)***PASS TO POINT N***(at 270°)*COME BACK IN POINT A

*(completing the second semi-circle of 180°)*

Which is the formula to calculate M and N?Which is the formula to calculate M and N?

On a - plain surface - i would have used the simple proportion of triangles to calculate them, but given is a sphere I don't know the formula to be applied.

I did some online search but I find a kind of difficult to figure it out.

I have been out of school from 15 years now, so I would like to ask if somebody can help me.

I hope my explanation is clear, thanks a lot if you can help!

Cheers

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