T–T scatter plots between Type-1, Type-2, Commander CO maps and the Dame et al. (2001) CO J = 1 → 0 map, smoothed to 1deg FWHM and pixelized with a HEALPix resolution parameter N_side = 64. The panels show correlations for J = 1 → 0 (top left), J = 2 → 1 (top right) and J = 3 → 2 (bottom left) line maps; the bottom right panel show correlations between the baseline 1deg FWHM Commander CO maps and the (smoothed) Type-1, Type-2 and the high-resolution Commander J = 2 → 1 map.