in 3 dimensions
Let P be a point in the given coordinate system
P = (x, y, z)
P = (\rho, \phi, z)
P = (r, \theta, \phi)
\begin{matrix} x &=& \rho \cos \phi \\ y &=& \rho \sin \phi \\ z &=& z \\ \end{matrix}
\begin{matrix} x &=& r \sin \theta \cos \phi \\ y &=& r \sin \theta \sin \phi \\ z &=& r \cos \theta \\ \end{matrix}
\begin{matrix} \rho &=& r \sin \theta \\ \phi &=& \phi \\ z &=& r \cos \theta \\ \end{matrix}