Coordinates
On a sphere or ellipsoid, the central angle is delineated along a great circle. The usually provided coordinates of a point on a sphere/ellipsoid is its conjugate latitude ("Lat"), and longitude ("Long"), . The "point", is actually—relative to the great circle it is being measured on—the transverse colatitude ("TvL"), and the central angle/angular distance is the difference between two TvLs, .
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