Simplified disk-integration factors and differences for a set of 1507 modes in a model rotating at 0.8 Ω_C, using 2D integrations and the harmonic projection method described in Lignières et al. (2006) and Lignières & Georgeot (2009). The resolutions are N_θ = 300 for both approaches, and N_φ = 720 for the 2D integrations. The inclination angle is i = 10°. Note: due to symmetries in the simplified visibility calculations, the visibilities of some modes cancel out and were therefore not included in this plot (see text for details).