In mathematics, a conformal map is a function which preserves angles. In the most common case the function is between domains in the complex plane. More formally, a map w = f(z), is called conformal (or angle-preserving) at z0 if it preserves oriented angles between curves through z0, as well as their orientation, i.e. direction. Conformal maps preserve both angles and the shapes of infinitesimally small figures, but not necessarily their size. The conformal property may be described in terms of the Jacobian derivative matrix of a coordinate transformation. If the Jacobian matrix of the transformation is everywhere a scalar times a rotation matrix, then the transformation is conformal. Conformal maps can be defined between domains in higher dimensional Euclidean spaces, and more generally on a Riemannian manifold.