(r−v) diagrams of the Hii region G327.3–0.5 obtained from the ¹²CO(6–5) (left) and from the 1₁₁–0₀₀-p H₂O (right) data cubes. The radius axis is the distance to the shell expansion center, chosen to be the peak of the cm continuum emission. The black solid half-ellipse represents an ideal shell in (r−v) diagram with an expansion velocity of 5 km s^-1 centered on –50 km s^-1, the dashed white half-ellipse an ideal shell with an expansion velocity of 6.5 km s^-1 centered on –45 km s^-1.