Loxodrome

angle relative tothe longitude

limit

rotate great circles

x

z

longitude

If a point moves on the surface of a sphere so that it maintains a constant angle to a pole, then its path follows a spherical spiral (or a rhumb line). On a general surface of revolution, a point making a constant angle with the the meridians (the intersections of the surface and the planes through the axis) follows a curve called a loxodrome.