- #1
yungman
- 5,718
- 241
If I specify the latitudes and longitudes of both point A and B on the surface of a unit sphere, how can I find the great circle angle between the two points?
Say if Latitude and longitude of A is ##\epsilon_1 \;\hbox { and }\;\tau_1## respectively. Latitude and longitude of B is ##\epsilon_2 \;\hbox { and }\;\tau_2## respectively. How do I find the angle between A and B?
I know in spherical trig.,
##\frac {\sin A}{\sin a}\;=\;\frac {\sin B}{\sin b}\;=\;\frac {\sin C}{\sin c}##
##\cos a\;=\;\cos b \cos c-\sin b\sin c\cos A##
I know how to find the great circle angle for each point as they both form a right angle spherical triangle. I don't have enough to find the great circle angle between the two points because they don't form a right angle spherical triangle. I found this:
http://en.wikipedia.org/wiki/Great-circle_distance
Can anyone explain how the equation come about?
Thanks
Say if Latitude and longitude of A is ##\epsilon_1 \;\hbox { and }\;\tau_1## respectively. Latitude and longitude of B is ##\epsilon_2 \;\hbox { and }\;\tau_2## respectively. How do I find the angle between A and B?
I know in spherical trig.,
##\frac {\sin A}{\sin a}\;=\;\frac {\sin B}{\sin b}\;=\;\frac {\sin C}{\sin c}##
##\cos a\;=\;\cos b \cos c-\sin b\sin c\cos A##
I know how to find the great circle angle for each point as they both form a right angle spherical triangle. I don't have enough to find the great circle angle between the two points because they don't form a right angle spherical triangle. I found this:
http://en.wikipedia.org/wiki/Great-circle_distance
Can anyone explain how the equation come about?
Thanks
Last edited: