Perimeter-area relationship where the two parameters have been summed over all the 5σ-RoIs identified in each ALMAGAL field. The black and green lines represent Eq. (1) in the case of a single circular shape or where the assumed perimeter is distributed for five circular shapes. The red and blue lines indicate the cases for a single ellipse with aspect ratio a.r. = 3 and 10 elliptical shapes with a.r. = 5. The vertical dashed(dotted) lines show the median area of the 7M+TM2+TM1 beam for the far/(near) sources (from Sanchez-Monge et al. 2025).