Emission line ratio diagnostic grids from the mappings 5.1 photo-ionization code for a plane-parallel geometry with P_k = 5.0 and κ = ∞. Each circle corresponds to one simulation with a specific abundance and ionization parameter. Small crosses indicate the location of each of the 556 circular apertures, color-coded as a function of the combined (where suitable) abundance value derived from both diagnostics. Orange crosses mark the apertures for which pyqz could not derive a reliable abundance: either from an overly large discrepancy between both grids, or because the estimates fall outside both grids.