Topic category

• Elevation

Use limitation

General 

Classification

Unclassified  

Description

LiDAR was acquired in ellipsoid co-ordinates by logging against a position solution obtained from the onboard IMU and GPS and the Victorian CORS network. The LiDAR was then checked against an ellipsoid control composed of surveyed ground control points and adjusted if required. The ellipsoid co-ordinates were then reduced to AHD using AusGeoid09 (Beta 7 and V1.01). Checks against AHD control resulted in a further general and local adjustments where required. An automated algorithm, tailored to the project, was used to classify ground and non ground returns. The results were manually checked using intensity imagery and the algorithm adjusted and the process reiterated until a clean ground surface was produced. Points more than 30cm above the classified ground surface are classified as non ground. 

Classification

Unclassified  

Attribute Quality

Positional Accuracy

Conceptual Consistency

Comments

Accuracy of the ground surface under dense canopy may be reduced. Laser accuracy at swath edges may be reduced. There is no difference in the processing of returns over water and over land. 

Missing Data

Comments

Gaps in the point cloud may have occurred due to gate range restrictions over areas with large terrain elevation differences. These were reflown to ensure full coverage. Gaps may occur due to diminished returns over water and materials with low laser reflectivity, such as black composite roofing. 

Excess Data

Platform Type

Aerial  

Assembly

Single  

Tile Size

1 km  

Scan Rate (Hz)

37Hz  

Footprint Size (m)

0.36000001m  

Point Density Actual (pts/m2)

2points/m2  

Ellipsoid Provided

0