Bottom-up trajectory generators lose the long tail: ScaleTraj picks a movement scale before it picks a destination cell
Individual-level trajectory generators can produce plausible single traces, yet once many individuals are aggregated their displacement distribution often misses the heavy tail of real data. ScaleTraj splits next-location prediction into two steps: a Scale Selection Head decides which spatial scale a move belongs to, and a Scale-Aware Cell Selection Head predicts the destination conditioned on that scale. On GeoLife and Tencent Beijing it lowers both the Scale Fidelity Profile error and the deviations of the fitted truncated power-law parameters relative to the compared model-driven and data-driven baselines.