Title

Melbourne Geoid - LiDAR 

Time period

2012-02-062012-03-09 

Horizontal Accuracy

0.3m  

Vertical Accuracy

0.1m  

Code

MGA Zone 55 GDA94 

Title

LAS 1.2 

Topic category

• Elevation

Use limitation

Restricted 

Classification

Restricted  

Description

Work flow stages: 1. Archived data from existing projects was retrieved (this included surrounding projects) 2. New areas of Test Points were surveyed and collected (5 new sites and 400 plus points) 3. Data was classified into ground and non-ground points using a single algorithim and modelled to AHD. Two separate versions were created using two different Geoid Models: 1. Ausgeoid09 and 2. Melbourne Geoid 4. An assessment of the Test Points against the modelled data was made. 5. A tilt in a general east-west direction was observed when the Test Points were compared to both the Ausgeoid09 and Melbourne Geoid datasets. 6. An adjustment tilt was applied to obtain a better fit to Test Points (+6cm at the western edge and -6cm at the eastern edge). 7. An assessment to validate adequate edge joins to adjacent projects was also undertaken. Work was conducted between September and November 2014 by AAM using original 2011 Melbourne Structural Vegatation LiDAR data as source data. Adjacent (edge-matched) projects include: Vic Coastal LiDAR, Geelong North - Anakie & Golden Plains LiDAR and the LARA LiDAR data (itself being reprocessed 2011 Melbourne Structural Vegatation LiDAR data). 

Classification

Unclassified  

Attribute Quality

Positional Accuracy

Conceptual Consistency

Comments

Both Ausgoid09 and Melbourne Geoid datasets meet all specifications and adhere to format and naming standards. The original source dataset for Melbourne Structural Vegetation LiDAR has a vertical accuracy of 0.2m (RMSE). The reprocessed datasets supplied in this project both have increased the vertical accuracy to 0.10m (RMSE). The dataset referenced to AHD using Ausgeoid09 reveals a marginally better fit to test points and should be used in preference to the Melbourne Geoid version. 

Missing Data

Comments

The LiDAR dataset is complete for the whole reprocessed AOI. LiDAR data from adjacent projects assessed in the edge matching process have not been supplied in this dataset. Cut-lines used to define overlap-merge zones between data sets have been supplied. Tilt adjustment details have been supplied with the project. 

Excess Data

Platform Type

Aerial  

Assembly

Single  

Tile Size

2 km  

Pulse Mode

Single Pulse 

Scan Rate (Hz)

45Hz  

Scan Frequency (kHz)

100kHz  

Scan Angle (degrees)

22degrees  

Footprint Size (m)

0.36000001m  

Point Density Target (pts/m2)

2points/m2  

Point Density Actual (pts/m2)

4points/m2  

Point Spacing Actual (pts/m)

0.5points/m2  

Ellipsoid Provided

0 

Geoid Vertical Datum

MELBOURNEGEOID08  

Additional Adjustments

A tilt was applied on top of the MelbourneGeoid model. The tilt is supplied with the project data set and ranges from -0.06m to 0.06m west to east. 

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	0	1	1	1	1	1	1	1	1	1	1	0