LiDAR Data in New Zealand: Free Access and Practical Uses
New Zealand offers extensive free LiDAR coverage through the LINZ Data Service. This data is transforming everything from flood modelling to forestry management.
Light Detection and Ranging (LiDAR) technology uses laser pulses fired from aircraft to create incredibly detailed 3D models of the earth's surface. New Zealand has invested heavily in LiDAR data capture over the past decade, and the results are freely available to anyone through the LINZ Data Service and the OpenTopography platform.
What LiDAR Data Looks Like
A typical LiDAR survey produces a point cloud — millions of individual 3D points representing the ground surface, vegetation, buildings, and other features. The raw point cloud is classified into categories: ground, vegetation, buildings, water, and so on. From the ground-classified points, a bare-earth Digital Elevation Model (DEM) can be generated.
The resolution is impressive. Many New Zealand LiDAR datasets have point densities of 2-8 points per square metre, with vertical accuracy of 100-200mm. This is far more detailed than contour data derived from aerial photography.
Accessing Free LiDAR Data
The LINZ Data Service (data.linz.govt.nz) hosts LiDAR-derived DEMs and point clouds for much of New Zealand. Coverage has been expanding rapidly, particularly after the Canterbury earthquakes drove a need for accurate elevation data for rebuild planning and flood modelling.
Regional councils have also been major commissioners of LiDAR data. Horizons (Manawatu-Whanganui), Hawke's Bay, Canterbury, and Otago all have extensive coverage. The data is typically available in LAS/LAZ format for point clouds and GeoTIFF for raster DEMs.
Practical Applications
The uses are wide-ranging:
- Flood modelling: Accurate elevation data is essential for predicting where floodwaters will go. LiDAR-derived DEMs are the foundation of most flood hazard assessments in New Zealand.
- Coastal erosion: Repeat LiDAR surveys can quantify coastal change over time, measuring cliff retreat and beach volume changes.
- Forestry: LiDAR can measure tree heights, canopy density, and estimate timber volumes without setting foot in the forest.
- Archaeology: Subtle earthworks and archaeological features invisible under vegetation can be revealed in LiDAR hillshade models.
- Infrastructure planning: Road and rail corridor surveys, pipeline route selection, and dam site investigations all benefit from high-resolution terrain models.
Processing LiDAR Data
Free tools like CloudCompare, LAStools, and QGIS can handle LiDAR data. For larger datasets and more sophisticated analysis, commercial packages like Esri ArcGIS Pro, Trimble Business Center, and Global Mapper offer comprehensive LiDAR processing capabilities. The learning curve is moderate — anyone comfortable with GIS should be able to work with LiDAR-derived products within a few hours of practice.