Constant K_MIN_ANGLE_SPAN 

pub const K_MIN_ANGLE_SPAN: LengthMetric;

Available on crate features quadratic or tan or linear only.

Each cell is bounded by four planes passing through its four edges and the center of the sphere. These metrics relate to the angle between each pair of opposite bounding planes, or equivalently, between the planes corresponding to two different s-values or two different t-values. For example, the maximum angle between opposite bounding planes for a cell at level k is kMaxAngleSpan.GetValue(k), and the average angle span for all cells at level k is approximately kAvgAngleSpan.GetValue(k).