Various quantities for the CDM (right-hand side) and fSIDM (left-hand side) haloes (the colours are the same as in Fig. 1) are shown as a function of r̃_ell. First row: shape profile as the ratio of the major and minor axis is shown. The mass tensor was measured within ellipsoids. Second row: density profile is shown as inferred from the ellipsoids used for the shape measurement by taking the differences in mass and volume between two consecutive ellipsoids. Third row: number of particles enclosed in the ellipsoid is shown. Fourth row: shape sensitivity, ξ, is shown according to Eq. (9). Here the vertical line indicates the criterion above which the shape was measured accurately, ξ = 10.