  We propose a practical recipe to compute the ${s}$-parametrized maps for
systems with $SU(1,1)$ symmetry using a connection between the ${Q}$ and ${P} $
symbols through the action of an operator invariant under the group. The
particular case of the self-dual (Wigner) phase-space functions, defined on the
upper sheet of the two-sheet hyperboloid (or, equivalently, inside the
Poincar\'{e} disc) are analyzed.
