Results for GalA. a) HI surface density in M_⊙ pc^-2 from the combined VLA observations. The spacing between the contours is 5 M_⊙ pc^-2. b) Line-of-sight velocity map of HI observed using the VLA. The Δv spacing between the contours is 14 km s^-1. c) Velocity dispersion map. The spacing between the contours is 5 km s^-1. d) Rotation curve of the HI disc observed with the VLA. The curves are obtained from the tilted ring model described in the text. e): HI residual velocity field. The contours are at −10, 0 and 10 km s^-1. f) Stellar surface density map obtained from the B-band luminosity determined from IFU observations and a colour-dependent mass-to-light ratio (Bell et al. 2003). In these maps, north is at the top and east is on the left-hand side.