Anisotropic spacing of drumlins: transverse quasi-regularity at the bedform scale versus along-flow clustering in the BRITICE record

Direction-resolved point-pattern analysis of 41,702 drumlins from the BRITICE v2 record of Great Britain. Drumlin spacing is strongly anisotropic: isotropic nearest-neighbour statistics are clustered (Clark–Evans R ≤ 1 in all nine coherent fields analysed; bedforms in along-flow trains), while the across-flow pair correlation shows hard-core exclusion and a characteristic transverse spacing λ⊥ ≈ 250 m, of the same order as the drumlin width. Compared with a width-matched hard-rod (Tonks-gas) steric null, the transverse first-neighbour spacing is largely accounted for by steric exclusion, with only weak longer-range periodicity beyond it; the pattern is not hyperuniform. Isotropic spacing regularity is therefore a weak diagnostic of subglacial bed-instability theories. Includes all analysis code, the derived drumlin-centroid dataset and figure-generation scripts.