application of multi-source uav data to assess...

Application of multi-source UAV data to assess revegetation efforts on waste rock

Tim Whiteside, Renée Bartolo & James BoydenEnvironmental Research Institute of the Supervising Scientist

Outline of this talk• Background to the Trial

Landform at Ranger• Project aim• Data capture and analysis• Some preliminary results• Concluding comments &• What’s next

5 Jan 12

3

Location• Northern Australia

• Mining lease established before declaration of Kakadu National Park

• Surrounded by Kakadu National Park

• Tropical monsoonal climate with distinct wet & dry seasons

• ~1550 mm annual rainfall

Ranger Uranium Mine• Scheduled for closure

in 2026

• Final landform will be mostly waste rock

• Established a trial landform to understand waste rock behaviour

• Information about:

– Material transport

– Hydrology

– Vegetation

• Helps inform closure criteria, calibrate models etc.

Construction

Mixing

■ Construction 2008-2009■ Built in layers■ Waste rock & lateritic

material

■ Mixed using an excavator■ Levelled with large

bulldozer■ Estimated cost of $10

million

7

Trial Landform (TLF)

1 2 3 4

Plots 1&2 Waste rock only

Plots 3&4 Waste rock &laterite mix

Vegetation• Tubestock planted on EP1

& EP4 - March 2009

• Direct seeding occurred on EP2 & EP3 -July 2009

• Some infill planting -tubestock on EP1 & EP4 –Jan 2010

• Direct seeding had poor germination, infill planted with tubestock Jan 2011

• Relied in natural recruitment since

Need images of the vegetation Perhaps before and after

6 May 12

10 Dec 09

TLF vegetation now• On site for 8-9 years

• Tree stem diameters > 5 cm

• No understorey yet on plots 1&2

• Due to substrate plots 3&4 has understorey (mostly weeds) and is managed

To assess ongoing viability of an established revegetation effort on waste rock

Resilience – fire, seasonality, substrateSpecies composition

Using UAS data – major benefit is data frequency and full site coverage

Primary aim of this project

Bungee launch

Skycam UAV - Swampfox

Parachute recovery

3DRobotics – X8+

Gryphon Dynamics – X8 1400

Year Date Fixed Multi RedEdge HS LiDAR RGB

2016 17 May

28 July

14 October

16 November

2017 18 January

26 April

18 May

Data captures to date - TLFFixed wing flights at 100 m altMulti rotor MS and HS flights at 70 mLidar at 30 m

• RGB and multispectral data processed using Pix4D Mapper

• MS radiometric calibration to reference panel

• Up to 8 GCPs used – DGPS recorded

• All RGB and MS data co-registered to May 2016 data

Data processing

Multispectral time series

Controlled burn18-19 May 2016

Multispectral time series

Multispectral time series

Multispectral time series

Multispectral time series

Multispectral time series

Object-based analysis of cover pre- and post-burn

• Multiresolution segmentation

• Random Forest classifier

• Accuracy assessment

• RGB data used for segmention

• Based on mainly on multispectral data

• Point based from mosaic

Object-based approach

Features used

Random Forest parameters

AccuraciesTrees vs non-trees92% accuracy

Weeds vs non-weeds85% accuracy200 stratified random points per class

AccuraciesTrees vs non-trees91% accuracyWeeds vs non-weeds95%200 stratified random points per class

Building up a field reference dataset

Conclusion

• UAV data enables high temporal analysis of rehabilitation sites at the plant level.

• Enables the monitoring of seasonal effects (eg phenology, water stress), plant fate and fire effects for the whole of a site.

So far:

• Strengths

‒ Coverage for whole of site ~ 30 min

‒ Cost effective multi-temporal data set

• Challenges

– Remote locality

– Terrain

– Erectophile leaves

– Sparse canopies

– Wind and thin stems

Strengths and challenges

Further work• Continued data collection including hyperspectral

and LiDAR data

• Using the multi-temporal UAV data to describe:

‒ Further analysis of structural, spectral and textural information to discriminate tree and ground cover

‒ Plant object fate analysis as site matures further

‒ Surface behaviour – including particle movement

Thank you.

Any questions?