Positions of all 685 galaxies in the Hα sample. Galaxies represented by star symbols are not in galaxy groups, while square symbols are in poor groups and triangle symbols are in rich groups. Galaxies considered inside filaments (under 2.70 Mpc from the spine of a given filament) have opaque symbols and thicker black edges while those outside the filament have translucent symbols and thinner black edges. We have indicated the Virgo cluster as a black circle. The radius corresponds to the virial radius of 1.55 Mpc (McLaughlin 1999). In the left panel, we give the 13 filaments studied in Castignani et al. (2022b) in different colours and use the same colours to mark galaxies as being nearest to a given filament. In the right panel, we colour both the filaments and galaxies by line-of-sight distance to highlight the complex 3D structure determining filament membership.