Steradian
The steradian (symbol: sr) or square radian is the unit of solid angle in the International System of Units (SI). It is used in three-dimensional geometry, and is analogous to the radian, which quanti
Square degree
A square degree (deg2) is a non-SI unit measure of solid angle. Other denotations include sq. deg. and (°)2. Just as degrees are used to measure parts of a circle, square degrees are used to measure p
Spat (angular unit)
The spat (symbol sp), from the Latin spatium ("space"), is a unit of solid angle. 1 spat is equal to 4π steradians or approximately 41253 square degrees of solid angle (sequence in the OEIS). Thus it