Access to data
Will the LIDAR point clouds be publicly available?
Point clouds are expected to be available on the LINZ Data Service by the end of 2025. Digital elevation models, digital surface models, intensity data and aerial imagery will also be available.
Will aerial imagery be publicly available?
Yes, aerial imagery will be made available on the LINZ Data Service. Digital elevation models, digital surface models, point cloud data and intensity data will also be available.
Flights
How high and fast does the plane fly?
The aircraft generally fly about 500 metres above the ground, at speeds of 130 knots or 240 km/hour. There have been occasions when the aircraft have flown higher, at 600 metres. This was in accordance with flight restrictions over the Cape Kidnappers Gannet Colony and the Royal Albatross colony at Harrington Point on the Otago Peninsula.
What types of planes are being used?
The two New Zealand based and operated aircraft are a Rockwell Turbo Commander and a Reims-Cessna F406 Caravan II.
Joining land and sea data
Land and seafloor elevation data are often on different vertical datums. How will the two be joined together at the land/sea interface?
The LiDAR data collected for the programme, across the land/sea interface, is in terms of the New Zealand Vertical Datum 2016 (NZVD2016). Topographic LiDAR collected as part of other programmes, such as PGF LiDAR, is generally in terms of NZVD2016, so joining these two datasets together will be straight forward.
The biggest challenge arises when we want to join our existing bathymetry data, that may be in a different vertical datum, such as Mean Sea Level or Lowest Astronomical Tide.
We are currently working on addressing this challenge through a piece of work called ‘Joining Land and Sea’, which is a part of our programme scope. This will provide a tool that will enable users to shift data from one vertical datum to another, supporting seamless mapping and modelling across our entire coastline.
Quality
What do you check during QA?
During the QA process we check the data accuracy against existing high resolution bathymetric and topographic data. We also check the classification and density of the point clouds, that there are no artifacts in the DEMs and DSMs and that all metadata has been correctly encoded.
Scope
How much of New Zealand’s coastline are you mapping?
The scope of the programme is to map up to 40% of New Zealand’s coastline extending, nominally, 200m inland of the Mean High-Water Spring (MHWS) coastline and seaward to a water depth of 25m, nominally, 200m inland of the Mean High-Water Spring (MHWS) coastline and seaward to a water depth of 25m. This coverage is just over 10,000 square kilometres.
Can additional areas be added to the programme scope?
When preparing for this programme we had conversations with key stakeholders to identify the areas to be mapped. The objective of the programme is to map up to 40% of New Zealand’s coastline and we need to work within our budget to achieve this.
It is unlikely that additional areas can be accommodated within the programme scope, however if external stakeholders have funding available, we are happy to discuss your requirements and can be contacted at 3DCM@linz.govt.nz.
How did you determine the programme scope?
The programme scope focuses on coastal areas with substantial population and/or vulnerable infrastructure such as significant roads, rail, electricity grids, and pipework. Key stakeholders were consulted in the identification of the areas to be mapped, ensuring we are focussing on the highest priority areas.
Technology and performance
What challenges have you encountered using the LiDAR technology?
When planning the work, we were fully aware of the challenges of the New Zealand environment, especially surf zones and turbidity which can affect collecting bathymetry.
As LiDAR uses laser light to penetrate the water, aeration from surf or suspended sediment particles causing turbidity, will prevent the light from reaching the seafloor. To overcome these challenges, we have included a number of re-flights to fill in any gaps caused by surf and/or turbidity.
During the planning stages, LINZ and the suppliers used satellite imagery and ocean environmental data to analyse and assess water clarity for each month. This informed which areas should be mapped when. However, the summer of 2025 was not great and meant the aircraft moved around the country making the most of the weather and environmental conditions.
What types of LiDAR are used in coastal mapping?
Topographic LiDAR maps land features using near-infrared lasers and bathymetric LiDAR uses green lasers to penetrate water and map the seabed. Both suppliers are using sensors from the same manufacturer, Leica. The sensors are the Chiroptera 5X and the HawkEye 5X.
Why is LiDAR used in coastal environments?
LiDAR is ideal for coastal zones because it can rapidly cover large areas, mapping both the land and seafloor, producing a seamless dataset. It also reduces the risk associated with using boats to map the shallow water, which in some areas may not have been mapped before.
What factors affect LiDAR performance in coastal areas?
Water clarity (turbidity), tide levels, sun angle (to avoid glare off the sea surface), weather conditions, survey altitude and flight path planning.
What happens if the LiDAR doesn’t reach 25m depth?
If the LiDAR can’t map to the 25m depth due to turbidity or other environmental conditions, even after re-flights, we will use multi-beam echo sounders fitted to small boats to fill in the gaps.
Timeframes
When will you map the areas not started or not complete?
The 3DCM programme runs until June 2027. Our suppliers are scheduled to be back in New Zealand flying from October 2025- May 2026, weather dependent. Any scope not completed in the coming season will be completed late 2026/early 2027.