Location of the strips and boxes used for fitting vertical radio continuum intensity profiles overlaid on the LOFAR map of NGC 891. The red lines denote the measured scale heights of the thick disc for each strip, the blue lines denote the measured scale heights of the thin disc for each strip. We use three strips with a width in terms of the effective radius r_e of 2/3 r_e. For NGC 891, we calculate the average intensity in 60 boxes per strip, each box with a height of 3″, corresponding to approximately half of our angular resolution.