Square degree

A square degree (deg2) is a non-SI-compliant 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 parts of a sphere. Analogous to one degree being equal to π/180 radians, a square degree is equal to (π/180)2 squared radians (i.e. steradians or sr), or about 1/3283 sr = 3.0462×10−4 sr (0.30462 msr). A square degree (deg2) is a non-SI-compliant 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 parts of a sphere. Analogous to one degree being equal to π/180 radians, a square degree is equal to (π/180)2 squared radians (i.e. steradians or sr), or about 1/3283 sr = 3.0462×10−4 sr (0.30462 msr). The number of square degrees in a whole sphere is approximately 41253 deg2.