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Coast and estuaries

Coastal mapping needs several vertical and temporal references: shoreline position depends on tide, wave conditions, datum, image date and the feature being digitised.

National/regional sources​

Useful starting points include:

  • MfE Data Service coastal hydrosystems and environmental-reporting layers
  • LAWA estuary-health monitoring
  • regional council coastal hazard/monitoring layers
  • LINZ nautical/topographic/coastline context
  • LINZ historical/current aerial imagery
  • LiDAR coastal terrain

A shoreline is not one universal line​

Possible shoreline indicators include vegetation edge, wet/dry line, cliff toe/top, mean-high-water concepts or mapped legal boundaries. Record which one was used before calculating movement.

Estuary monitoring​

LAWA publishes common estuary indicators including mud content, contaminants and macrofauna for monitored estuaries. Monitoring sites and sediment samples are not a complete surface of the whole estuary.

Change workflow​

Use imagery change over time plus LiDAR and council coastal datasets. If elevation or inundation is involved, verify the vertical datum.

Last reviewed: 26 August 2026

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