Released by LINZ under Creative Commons Attribution 4.0 New Zealand (CC BY 4.0) with:
Following Attribution: "Sourced from the LINZ Data Service and licensed by Gisborne District Council for re-use under CC BY 4.0." For details see: https://www.linz.govt.nz/data/licensing-and-using-data/attributing-elevation-or-aerial-imagery-data
Data Acquisition: LiDAR survey was collected using Aerial Surveys Optech Orion H300 LiDAR system. The original data comprised 5 blocks and was combined into one dataset before publishing.
Please refer to survey reports for survey specifications.
Data Processing: The LiDAR sensor positioning and orientation (POS) was determined using the collected GPS/IMU datasets and Applanix POSPac software.
Please refer to survey reports for benchmark and base station information.
The POS data was combined with the LiDAR range files and used to generate LIDAR point clouds in NZTM and ellipsoidal heights. This process was undertaken using Optech LMS LiDAR processing software. The data was checked for completeness of coverage. The relative fit of data in the overlap between strips was also checked.
Please refer to survey reports for height accuracy summary statistics.
The positional accuracy of the LiDAR data has been checked by overlaying Sounds Surveying Ltd surveyed data over the LiDAR data displayed as first return TIN surface. The data was found to fit well in position.The point cloud data was then classified with TerraSolid LiDAR processing software into ground and above ground returns using automated routines tailored to the project landcover and terrain.
All product deliverables supplied in terms of NZTM map projection and NZVD2016 vertical datum.
Classification of the point cloud followed the clasification scheme below: 1 - Unclassified 2 - Ground 7 - Low Noise 9 - Water 18 - High Noise
All points that did not fall into one of these classification types were reclassified to follow LAS 1.4(6) specification.
LINZ also removed bridges found in the Digital Elevation Model. Lakes and large rivers were hydroflattened in the Digital Elevation Model.
Issues in the DEM and DSM tiles were fixed by LINZ and involved the removal of spikes and dips, data voids, edge artefacts between block deliverables and bridges in the DEM.
The deliverables to LINZ were:
1m gridded bare earth digital elevation model (DEM) 1m gridded digital surface model (DSM) Classified point cloud