Location of the large-scale filaments (LSFs) across the Milky Way disc. Inner Galaxy LSFs and outer Galaxy LSFs are indicated with red and green contoured circles, respectively. The size of the circles is proportional to the filament lengths. The inner colours of markers show the velocity offset (ΔV_sp.arm) with respect to the closest spiral arm (see the colour scale on the right). White-filled markers are for inner Galaxy LSFs where this quantity is not provided by their original catalogues. Inner Galaxy giant molecular filaments (GMFs) are highlighted with red dots. Coloured full lines mark the position of the spiral arms following Taylor & Cordes (1993) models, as adapted in Urquhart et al. (2021). The ‘Local’ arm (or spur) parameters are taken from Reid et al. (2019). Dotted coloured lines show the correspondent spiral arm loci from Reid et al. (2016), used to define the spiral arm associations in the inner Galaxy. Galactocentric circles drawn with black dotted lines are spaced 2 kpc apart. Cyan dashed arcs show loci with equal velocity between 20–120 km s⁻¹ (from the Galactic centre outwards) and spaced 20 km s⁻¹ apart. The cyan ‘X’ indicates the Galactic centre and ‘⊙’ the position of Sun. The figure was produced using the MW-PLOT package (available at https://milkyway-plot.readthedocs.io/en/latest/).