Linewidth-size (top) and mass-size (bottom) relations for the clouds and apertures. Clouds are shown in blue, and the symbol size is proportional to the cloud mass. The error bars are as described in Sect. 2.3. Apertures are shown in orange, with error bars indicating the standard deviation between the apertures. The solid blue line shows a fit to the cloud data, the dashed orange line shows a fit to the aperture data, and the dotted grey line shows the fit from Larson (1981).