regionCone

The cone a region occupies, measured from its own corners.

The four edges of a cell are great-circle arcs — fixing u traces a plane through the origin — so the cell is a convex spherical quadrilateral and its farthest point from the center is a corner. The cone therefore contains it exactly, which is what lets the horizon test and the distance be conservative without a fudge factor.

regionRegionAddress

Undocumented