My name is Toby Clewett and I use GIS technology for geospatial analysis and modelling at Sunshine Coast Council. Last year, our GIS team captured the interest of our region – when we decided to survey tree heights across the area. At the time, none of us imagined it would lead to the discovery of a new environmental icon: Queensland’s tallest tree.
Dubbed ‘Big Bob’ – in honour of long-serving Sunshine Coast councilor and former mayor Bob Abbot – the 73 metre giant was found hidden in the rugged forest of Conondale National Park, using a combination of GIS and Light Detection and Ranging (LiDAR) technology.
You can read more about how we made the discovery here – but basically, in addition to finding ‘Big Bob’, we were also able to generate an extremely accurate picture of what Conondale National Park actually looks like – right down to the rocks, shrubs, landslips and former forestry tracks of the bare landscape. The two videos below show a visualisation of LiDAR data from the area:
- Visualisation of Vegetation GIS Mapping using LiDAR; and,
- Vegetation Mapping using LiDAR Point Cloud Data – 3D Visualisation.
However, we wanted to be sure of the accuracy of the method – and after an off-track field trip, we were able to get cold, hard proof that it works!
Late last year, we thought we would put the GIS and LiDAR solution to the test, by conducting a ‘quality assurance’ exercise. Together with my colleagues – Dean Derby and Lee King – we took Julia and David Pennisi (who are two famous Australian tree climbing champions… known as ‘climbing arborists’), out to the tree to climb and measure it!
It was incredible to witness David climbing to within four metres of the highest branch, and then using an aluminium extension pole to hoist a tape measure to the highest branch.
Communicating via CB radio with Lee at the base of the tree, David dropped the tape measure and we were able to establish the height at 72.84 metres – just 6 centimetres different to the 72.90 metres measured by LiDAR.
It was a fun and fascinating exercise – and proved once and for all just how accurate we can be by leveraging GIS and LiDAR technologies to get a clear and detailed picture of the landscape and its features.
If you’re interested in LiDAR technology you might also like to check out my university thesis – ‘Application of LiDAR Technology Mapping for Vegetation Management – A Survey of south-east Queensland’s Professionals’.
Toby Clewett, Geospatial Analyst, Sunshine Coast Council.