This layer contains the DEM for LiDAR data from the Cheviot area captured in 2015. The DSM is available as layer [Canterbury - Cheviot LiDAR 1m DSM (2015)](http://data.linz.govt.nz/layer/3549). The index tiles are available as layer [Canterbury - Cheviot LiDAR Index Tiles (2015)](http://data.linz.govt.nz/layer/3571). The LAS point cloud and vendor project reports are available from [OpenTopography](https://portal.opentopography.org/datasets?loc=New%20Zealand).
Lidar was captured for Environment Canterbury Regional Council by Aerial Surveys on 1 April 2015, under survey name Hurunui. The datasets were generated by Aerial Surveys and their subcontractors. The survey area includes the Cheviot township area. Data management and distribution is by Land Information New Zealand.
Data comprises: •DEM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout •DSM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout •Point cloud: las tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout
Planned pulse density is 1.3 pulses/square metre.
Vertical accuracy specification is per the ICSM LiDAR Acquisition Specifications and Tender Template NZ Version March 2011.
Vertical datum is NZVD2016.
Data Acquisition: Airborne Laser Scanner (ALS) data was acquired from a fixed wing aircraft on 1 April 2015, using Aerial Surveys' Optech Orion H300 LiDAR system.
The LiDAR sensor positioning and orientation (POS) was determined using the collected GPS/IMU datasets and Applanix POSMMS software. This work was all undertaken in NZGD2000 coordinate system using the data collected from the following basestations:
Project: Ecan Cheviot Date of Capture: 1/4/15 Base Station Type/Owner: Global Surveys Bench Mark: GSCV Base Station Position: 42 48 46.88210 S 173 16 44.94167 E 85.7327 Ell Height Ant Height : 0.00 Phase Center Output LAS Projection: TM2000 Height: WGS84 Ellipsoid
Validation was carried out using the guidelines contained in the ICSM specification template as required for this program.
Vertical Accuracy Validation: The height accuracy of the LiDAR points was checked using check points collected during the ground control survey
Horizontal Accuracy Validation 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.
All product deliverables were initially supplied in terms of NZTM and Lyttelton 1937 height datum.
Classification of the point cloud followed the classification scheme below: 0 - Created, never classified 2 - Ground 12 - Flight line overlap points 14 - Above_Ground
Re-processing: In 2016 the data was reprocessed by Aerial Surveys for LINZ relative to the NZVD2016 vertical datum, and supplied as 1:1000 nominal scale (2500 720m high x 480m wide subtiles per full NZ Topo50 sheet). Lakes and 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
Data hosted by OpenTopography was re-classified: the Above_Ground (14) points were reclassified as Unassigned classification (1)