CoordinateTransformData

CoordinateTransformData[t, property] gives the value of the specified property for the coordinate transformation t.

CoordinateTransformData[t, property, {x1, x2, ..., xn}] gives the value of the property evaluated at the point.

Examples

Get the transformation mapping from Cartesian to polar:

CoordinateTransformData["Cartesian" -> "Polar", "Mapping", {x, y}]
(* {Sqrt[x^2 + y^2], ArcTan[x, y]} *)

Convert a specific point:

CoordinateTransformData["Cartesian" -> "Polar", "Mapping", {1, 1}]
(* {Sqrt[2], Pi/4} *)

Please visit the official Wolfram Language Reference for more details.