Weights of FASHI north galaxies. Left panel: Blue line shows the normalised surface density as a function of the rms noise of the FASHI galaxies in each pixel. We weighted each galaxy with the reciprocal of the best-fitting rms noise dependence function to correct the surface density to be homogeneous, shown as red line. Right panel: Weights in different pixels for FASHI north. We only used pixels with the weights in the range of 0.5–2 to prevent heavily weighted galaxies ending up assigned to less-sampled regions.