Cross sections of CO emission (or FIR 250 μm emission), extinction-corrected GALEX NUV emission (young stars with a mean age of 10 Myr; the hatched region corresponds to lower and upper limits of extinction) and Spitzer 3.6 μm NIR emission (characterising the overall stellar mass distribution) for the spiral segments. The horizontal axis shows the distance from the spine of the given spiral segment. Negative distances correspond to the inner side of a segment (closer to the galactic centre). The vertical axis shows the relative intensity of the corresponding star formation tracer. Narrow peaks in NIR emission distributions are due to local stars.