Correlation between CH and OH column densities derived using the WF deconvolution algorithm toward (clockwise from top left) AGAL010.624 − 00.384, AGAL034.258+00.154, AGAL327.293 − 00.579, AGAL330.954 − 00.182, AGAL332.826 − 00.549 and AGAL351.58 − 00.352. The different markers indicate contributions from spiral-arm (in blue), and inter-arm gas (in red). The linear regression is shown by the blue dashed line along with N(OH)/N(CH) ratios of 0.1, one and 10. Secondary x-axis represents H₂ column densities obtained using the CH/H₂ abundance ratio given by Sheffer et al. (2008). The corresponding Pearson’s correlation coefficients are given in the lower-right corners.