This question has been asked before, and answered and closed.
But need I some details (as I am new to 3D graphics).
The answer given by Super Moderator Dorbie (bag pipes) was:
"Any point on the sphere represents a vector from the center of the globe. Any two points are a pair of vectors. The best interpolation between those two vectors is a rotation about their cross product by an angle that is the acos of their dot product.
That should be simple to implement."
It sounds very simple, but I could use some example code.
TOO_THIRSTY