Airborne Laser Scanner (ALS) data was acquired from a fixed wing aircraft on: 15th, 20th, 22nd, 29th, 30th Nov 2018, 7th Dec 2018, 15th Jan 2019, 13th Feb 2019, using Aerial Surveys Optech Orion H300 LiDAR system.
- Scanner: Optech Orion H300
- Flying Height: 1300 m AMGL
- Scan Angle: ±30.0 degrees
- Scan Frequency: 41.5 Hz
- Pulse Rate: 100 kHz
- Swath Overlap: 35%
- Points Per Square Metre: 2.17
The LiDAR sensor positioning and orientation (POS) was determined using the collected GPS/IMU datasets and Applanix POSPac software.
Base Station: PP-RTX
Sounds Surveying Ltd field surveyed check sites that were used to verify the accuracy of the
processed ground dataset
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 coded by intensity. The data was found to fit well in position.
The point cloud data was then classified withTerraSolid 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 classification scheme below:
1 - Unclassified
2 - Ground
3 - Low Vegetation
4 - Medium Vegetation
5 - High Vegetation
6 - Building
7 - Low Noise
9 - Water
18 - High Noise
Lakes and large rivers were hydroflattened in the Bare Earth Digital Elevation Model.
The deliverables to LINZ were:
1m gridded bare earth digital elevation model (DEM)
1m gridded digital surface model (DSM)
Classified point cloud