Comparison between the warp amplitude obtained in this work and other parametrisations available in literature based on different stellar tracers. The blue shaded area shows the warp amplitude obtained in this work in the region where our dataset and our adopted approach allow us to reasonably constrain the warp shape. At larger galactocentric radii (R ≳ 12 kpc, grey shaded area), it is not possible for our approach to give a reliable estimate of the warp amplitude based on our dataset due the lack of convergence of the fitting routine (see discussion in the text).