Clustering results of the ch3-short cube (top) and the complete ch3 channel cube (bottom) for NGC 7172. Left panels: Median flux on a logarithmic scale of the ch3-short and ch3-all cube (top and bottom, respectively; see Appendix A). Middle panels: Cluster maps. Right panels: Median spectra per cluster on a logarithmic scale, normalised to the total integrated flux (see Sect. 2.2). The maps are centred on the original observed position (north is up and east to the left). The white star indicates the photometric centre. We assigned the same colours to the clusters and their respective spectrum. Colours were calculated automatically by dividing the ‘jet’ palette in MATPLOTLIB. We note that both the cluster colours and numbering are arbitrary, have no physical meaning, and are assigned independently in the top and bottom panels. We mark with dashed vertical grey lines the main emission lines, and with grey bands the PAH features in the spectrum. The wavelength is in rest frame.