  Amplitude- and truncated partial-wave analyses are combined into a single
procedure and a novel, almost theory-independent single-channel method for
extracting multipoles directly from measured data is developed. In practice, we
have created a two-step procedure which is fitted to the same data base: in the
first step we perform an energy independent amplitude analysis where continuity
is achieved by constraining the amplitude phase, and the result of this first
step is then taken as a constraint for the second step where a constrained,
energy independent, truncated partial-wave analysis is done. The method is
tested on the world collection of data for $\eta$ photoproduction, and the
obtained fit-results are very good. The sensitivity to different possible
choices of amplitude phase is investigated and it is demonstrated that the
present data base is insensitive to notable phase changes, due to an incomplete
database. New measurements are recommended to remedy the problem.
