Title

Greater Melbourne LiDAR - Point Cloud 

 

Time period

2017-11-282018-10-27 

 

Horizontal Accuracy

0.2m  

Vertical Accuracy

0.1m  

Code

MGA Zone 55 GDA2020 

 

 

Title

Other 

 

 

Topic category

• Elevation

 

Use limitation

General 

Classification

Unclassified  

 

Description

The IMU and post processed airborne GPS logs were used to generate the LiDAR point cloud from the waveform instrument data. Raw LiDAR swaths were levelled to establish internal consistency, merged and 1km x 1km tiles in LAS v1.2 format were created. An automatic classification algorithm was applied in TerraScan software to produce an initial classification of ground (2) and unclassified (1). High and low noise points were automatically classified and allocated to class 7. The ground classification was improved manually by visually scanning the ground surface and reassigning points from ground to unclassified to remove spikes and by assigning unclassified points to ground where the ground surface lacked sufficient detail to describe the terrain (i.e. large TIN triangles). The classification of ground points was to the ICSM level 2 standard (98% accuracy with respect to ground points). On completion of the ground classification automatic algorithms were used to classify unclassified points to low vegetation (3), medium vegetation (4), high vegetation (5), buildings (6), water (9) and bridge (10). Ground points were confirmed and retained. The classification accuracy was not measured empirically. Upon successful classification, the dataset was converted from ellipsoidal to orthometric using AusGeoid09, and tiles were regenerated to 1km x 1km and LAS v1.4. 

 

Classification

Unclassified  

 

Attribute Quality

Positional Accuracy

Conceptual Consistency

Comments

The data adheres to the logical rules of data structure, attribution and relationships as per project specifications. Dataset provided as LAS 1.4. 

Missing Data

Comments

Point cloud dataset is complete for the defined project extent. 

Excess Data

 

Platform Type

Aerial  

Assembly

Mosaic  

Tile Size

1 km  

 

 

Pulse Mode

Multipulse 1-8 

Scan Rate (Hz)

178Hz  

Scan Frequency (kHz)

400kHz  

Scan Angle (degrees)

30degrees  

Footprint Size (m)

0.12m  

Point Density Target (pts/m2)

8points/m2  

Point Density Actual (pts/m2)

8points/m2  

Point Spacing Target (pts/m)

0.34999999points/m2  

Point Spacing Actual (pts/m)

0.38points/m2  

Ellipsoid Provided

1 

Ellipsoid Vertical Datum

GRS80 Ellipsoidal (ITRF2005)  

Ellipsoid Format

Other  

Geoid Vertical Datum

AUSGEOID09  

Additional Adjustments

Provided as LAS 1.4 

Environmental Conditions

Project was specified to be flown in appropriate environmental conditions, free of cloud, fog and heavy smoke haze. 

Tidal Conditions

Coastal areas were specified to be captured within 2 hours of low tide. 

Class Level

2 

Classification

Class Level	Class 0 - Unclassified	Class 1 - Default	Class 2 - Ground	Class 3 - Low Vegetation	Class 4 - Medium Vegetation	Class 5 - High Vegetation	Class 6 - Buildings/Structures	Class 7 - Low/High Points	Class 8 - Model Key Points	Class 9- Water	Class 10 - Bridge	Class 12 - Flightline Overlap Points
2	1	1	1	1	1	1	1	1	1	1	1	0