Title

Glenthompson - LIDAR 

 

Time period

2016-03-152016-03-15 

 

Horizontal Accuracy

0.3m  

Vertical Accuracy

0.1m  

Code

MGA Zone 54 GDA94 

 

 

Title

LAS 1.3 

 

 

Topic category

• Elevation

 

Use limitation

General 

Classification

Unclassified  

 

Description

LiDAR was acquired over each project/site area. The acquired LiDAR strikes were transformed into an ellipsoid point cloud using a solution obtained from the onboard IMU and GPS and Victorian CORS network. The point cloud was then adjusted to AHD using AusGeoid09. Checks against an network of surveyed ground control resulted in further general and local adjustments where required. Reduction of the LiDAR data proceeded without any significant problems, Laser strikes were classified into ground and non-ground points using a single algorithm across the project area. Manual checking and editing of the data classification further improved the quality of the terrain model. 

 

Classification

Unclassified  

 

Attribute Quality

Positional Accuracy

Conceptual Consistency

Comments

Accuracy of the ground surface under dense canopy may be reduced due to diminished returns. Laser accuracy at swath edges may be reduced. Classification algorithms have been tailored for common terrain/vegetation combinations across the project area. Classification accuracy and ground definition may be less accurate in uncommon terrain/vegetation combinations. 

Missing Data

Comments

The point cloud data is complete for the defined project extent. Gaps may occur due to diminished returns over water, under canopy and on materials with low laser reflectivity, such as black roofing or swimming pools. 

Excess Data

 

Platform Type

Aerial  

Assembly

Single  

Tile Size

2 km  

 

 

Pulse Mode

Single 

Scan Rate (Hz)

66Hz  

Scan Frequency (kHz)

100kHz  

Scan Angle (degrees)

40degrees  

Footprint Size (m)

0.23m  

Point Density Target (pts/m2)

2points/m2  

Point Density Actual (pts/m2)

2points/m2  

Point Spacing Actual (pts/m)

0.70999998points/m2  

Ellipsoid Provided

1 

Ellipsoid Vertical Datum

AUSGEOID09  

Ellipsoid Format

LAS 1.3  

Geoid Vertical Datum

AUSGEOID09  

Additional Adjustments

Ground data in this dataset has been compared to 64 test points obtained by field survey and assumed to be error-free. The test points were distributed in a location on open clear ground. Comparison of the field test points with elevations interpolated from measured data resulted in a Mean Difference (m) of 0.292 and RMS (m) of 0.293. The mean difference at each site has been removed from the data. Final accuracy estimates after removing the mean offsets yielded a Mean Difference (m) of 0.001 and RMS (m) of 0.020. 

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	1