exslt-math:atan2

Returns the angle in radians subtended at the origin by the point on a plane with coordinates (x, y) and the positive x-axis, the result being in the range -π to +π. (Note the order of arguments (y, x). There are some maths libraries that implement an atan2 function with the arguments in the order (x, y).

atan2($y as xs:double, $x as xs:double) ➔ xs:double

Namespace

http://exslt.org/math

Links to specifications

EXSLT Math Module

Saxon availability

Requires Saxon-PE or Saxon-EE. Available for Java and C/C++ only (not .NET).

Notes on the Saxon implementation

Saxon also implements the function math:atan2() in namespace http://www.w3.org/2005/xpath-functions/math.