  The most recent high-precision data on spin observables $\Sigma$, $T$, $P'$,
$E$, $F$ and $H$ reported by the CLAS Collaboration together with the previous
data on differential cross sections and spin-density-matrix elements reported
by the CLAS, A2, GRAAL, SAPHIR and CBELSA/TAPS Collaborations for the reaction
$\gamma p \to \omega p$ are analyzed within an effective Lagrangian approach.
The reaction amplitude is constructed by considering the $t$-channel $\pi$ and
$\eta$ exchanges, the $s$-channel nucleon and nucleon resonances exchanges, the
$u$-channel nucleon exchange and the generalized contact current. The latter
accounts effectively for the interaction current and ensures that the full
photoproduction amplitude is gauge invariant. It is shown that all the
available CLAS data can be satisfactorily described by considering the
$N(1520)3/2^-$, $N(1700)3/2^-$, $N(1720)3/2^+$, $N(1860)5/2^+$, $N(1875)3/2^-$,
$N(1895)1/2^-$ and $N(2060)5/2^-$ resonances in the $s$-channel. The parameters
of these resonances are extracted and compared with those quoted by PDG.
