Definition:Complex Curvilinear Coordinates/Coordinate Curves

Definition
Let $u + i v = f: \left({x + i y}\right)$ be a complex transformation.

Let $c_1$ and $c_2$ be constants.

The curves:
 * $u \left({x, y}\right) = c_1$
 * $v \left({x, y}\right) = c_2$

are the coordinate curves of $f$.