Multi-return LiDAR and PPK photogrammetry along 14 km of open coast to establish a repeatable erosion baseline for hazard planning.
◇ Challenge
Dune toe and cliff-edge positions were being tracked from ad-hoc ground walks and historic aerials — no consistent vertical datum, no way to quantify volume loss between storms.
◇ Approach
Three tide-windowed VTOL flights per epoch with PPK corrections tied to LINZ marks. LiDAR classified to bare-earth beneath dune vegetation; orthomosaics stitched at 2.4 cm GSD for visual change detection.
◇ Outcome
A three-epoch surface-difference model showing 38,000 m³ of net sand loss across two winter storm sequences, delivered as GeoTIFF and 12d-ready contours for the council's hazard overlay review.