Radial distributions of the oxygen abundances in NGC 628. Panels of columns 1–2: radial distributions of abundances estimated through the R calibration (Col. 1) and S calibration (Col. 2). Panels of rows a–d: abundances based on the IFU measurements from PINGS (row a), from CALIFA survey (row b), from PHANGS survey (row c), and from VENGA survey (row d). The grey points denote the abundances for the individual H II regions (panels of rows a, b, c) or individual spatial samplings (panels of row d), and the dark circles mark the median value in bins of 0.1 in R/R₂₅ and the scatter of each bin. The red crosses in each panel designate the median values for the slit-spectra-based abundances (O/H)_R and (O/H)_S together) and come from Fig. 2.