H I scale height (top panel) and surface density (bottom panel) profiles for our fiducial H I model of the Milky Way. Profiles for QI and QIV are shown in red and blue respectively. The top panel shows the best-fit values to the data (points with error-bars) and the profiles derived by smoothing the latter to 0.2 kpc of resolution (thin solid lines), while only the smoothed profiles are shown in the bottom panel. The thick solid black lines show the mean profiles. For comparison, we show the density profiles determined by Binney & Merrifield (1998; dashed line), Nakanishi & Sofue (2003; dotted line) and Kalberla & Dedes (2008; dot-dashed line), all re-scaled to R_⊙ = 8.3 kpc.