Crystal ordering of opal-based self-assembled photonic crystals fabricated by vertical drawing deposition technique has been examined by the angle-resolved transmission spectroscopy. Assuming that minima in transmission spectra register the diffraction resonances occurring at different planes of the crystal lattice, the angle dispersions of these resonances reflect the ordering of the crystal lattice. Since such dispersions obtained as a function of the angle of light incidence cannot provide quantitative estimate of the crystal ordering without comparison to the adopted standard, we suggested to analyse the diffraction resonances as a function of the lattice rotation. This method allows to quantify the lattice ordering by the accuracy of the repetition of similar diffraction features upon the azimuth angle.