Temporal leakage

privacy

Publishing a sequence of snapshots over time for the same fine-grained cell (even if each snapshot independently meets k-anonymity) can let an observer intersect the snapshots to re-identify an individual whose presence changed between them.

Detection

Compare successive published snapshots for the same cell; check whether the intersection of 'present in snapshot A and B' sets drops below the k-anonymity threshold.

Mitigation

Apply k-anonymity to the full published time series, not each snapshot independently
Add temporal noise or coarsen the time grain when publishing repeated cuts of the same fine cell

Affected conversions

Point → H3 exact
Raster → H3 approximate