Class: pole
http://www.astro.umd.edu/~eshaya/astro-ont/owl/geometry.owl#pole
Annotations
- label: "pole" (string)
- definition: "One of 2 points on a sphere where the normal intersects the equator at a right angle. Also, the direction in spherical coordinates where the theta is + or - 90 degrees and phi is undefined." (string)