Wellington LiDAR 1m DSM (2013-2014)

Data Acquisition:
Airborne Laser Scanner (ALS) data was acquired from a fixed wing aircraft between 2013 and 2014 using Aerial Surveys' Optech ALTM 3100EA LiDAR system.

Project Scope:
Acquisition and delivery of Raw LiDAR Point Cloud Data over the entire Wellington region extending to 100m offshore
Acquisition of urban specification (high resolution) LiDAR data: Ground model of +/-0.1 to 0.15m in z (1 sigma) with a resolution of 1.3 points per square metre.
Post processing of the LiDAR data with data being delivered in separate flight lines using newly acquired ground control.

Survey Specification:
 Scanner: Optech ALTM 3100EA
 Flying height: 1000m AMGL
 Scan Angle: +/- 18.8 degrees
 Scan Frequency: 53Hz
 Pulse Rate 100kHz
 Swath Overlap: 50%
 Points Per Sqm: 1.73

Data processing:
The positional data collected from each flight by the POS-AV510 GPS/IMU system was processed using the Applanix POSMMS application.

The ground control survey was carried out by the registered surveyors C&R Surveyors.

All product deliverables supplied by Aerial Surveys in terms of NZTM map projection and Wellington 1953 Vertical Datum. The data was converted from NZGD2000 ellipsoidal heights into the local height system using the LINZ NZGeiod09 and Wellington 1953 offset.

The point cloud data was classified by Landcare Research per the modified ASPRS classification scheme below, using an automated (Level 1) classification process:

1 - Unassigned
2 - Ground
4 – Vegetation
9 – Water


Re-processing:
In 2016 the data was reprocessed by Landcare Research for LINZ relative to the NZVD2016 vertical datum, and the DEM and DSM supplied as 1:1000 nominal scale (2500 720m high x 480m wide subtiles per full NZ Topo50 sheet).The deliverables to LINZ were:

1m gridded bare earth digital elevation model (DEM)
1m gridded digital surface model (DSM)
Classified point cloud