De-projected image of the disk taking into account the measured disk inclination and height and assuming a power-law profile for the disk height structure. The red circle indicates the radial distance at which the spiral pitch angle was measured. For both spirals we indicate with a radial (cyan or green) arrow where we consider the intersection of the red circle with the spiral arm. The azimuthal cyan and green arrows indicate the measured spiral pitch angles for the western and southern arms respectively. This de-projection is based on the H-band data set.