$atan (aggregation)

$atan

New in version 4.2.

Returns the inverse tangent (arc tangent) of a value.

$atan has the following syntax:

{ $atan: <expression> }

$atan takes any valid expression that resolves to a number.

$atan returns values in radians. Use $radiansToDegrees operator to convert the output value from radians to degrees.

By default $atan returns values as a double. $atan can also return values as a 128-bit decimal as long as the <expression> resolves to a 128-bit decimal value.

For more information on expressions, see Expressions.