8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

1/23

Supervising Scientist - working to protect the environment from the impacts of uranium mining

www.environment.gov.au/ssd

A rule-set driven approach to classifying

vegetation from high spatial resolution imagery

Dr T Whiteside*, Dr R Bartolo# & G Staben+

* Remote Sensing Scientist, Spatial Sciences and Data Integration

# Program Leader, Spatial Sciences and Data Integration+NT Department of Natural Resources, Environment, The Arts and Sport

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

2/23

2Supervising Scientist Division

A vegetation map of the Magela floodplain

Ramsar wetland Dynamic vegetation cover

Downstream from Ranger minesite

Ecological risks

Weeds

Fire

Ferals

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

3/23

3Supervising Scientist Division

Vegetation map

GEOBIA approach Partitioning

Step-wise

Processing and analysis specific to region

Robust rule-set Transferrable (hopefully)

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

4/23

4Supervising Scientist Division

Study site

Magela Creek floodplain

"

"

!

JABIRU

OENPELLI

JABILUKA MINE

NorthernTerritory

!Darwin

!

!

!Jabiru

PineCreek

Darwin

0 10050 km

Mining Lease Boundary

Major Roads

Rivers

Kakadu National Park Boundary

Coastal Floodplains

Arnhem Land Plateau

m0 5 102.5 Kilometres

AlligatorRiversRegion

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

5/23

5Supervising Scientist Division

Data

WorldView-2 multispectral DEM

Mask of town and mine

,, s

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

6/23

6Supervising Scientist Division

Issues

Differing view angle for Region 1 Mixed cover on floodplain

Water

Some cloud cover/shadow

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

7/237Supervising Scientist Division

WorldView-2

0.5 m Panchromatic - 1 band 2 m Multispectral - 8 bands

surface reflectance

Red edge and 2 NIR bands

http://worldview2.digitalglobe.com/docs/spectralResponseOverview.pdf

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

8/238Supervising Scientist Division

Conceptual process diagram

Segment

Masks

Classify

Single classobjects?

No

Finish class

Yes

Split imagein objects

Based onclass rules/thresholds

Do objects

still contain amix of

classes?Iterativesegmentation/classification

approach

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

9/239Supervising Scientist Division

Mask out minesites and township

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

10/2310Supervising Scientist Division

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

11/2311Supervising Scientist Division

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

12/2312Supervising Scientist Division

Apply water mask

Threshold segmentation Pixels with low NIR1 values

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

13/2313Supervising Scientist Division

Delineate Floodplain using DEM

90 m SRTM DEM 10 m 2004 AP DEM

6 m threshold

10 m DEM90 m DEM

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

14/2314Supervising Scientist Division

FloodplainDEM - 6m threshold

10 m DEM90 m DEM

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

15/2315Supervising Scientist Division

6m threshold

10 m DEM90 m DEM

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

16/2316Supervising Scientist Division

5 m threshold

10 m DEM90 m DEM

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

17/2317Supervising Scientist Division

Cloud mask

Based on FDI (Bunting and Lucas 2006) FDI= NIR2 (Red Edge+ Blue)

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

18/2318Supervising Scientist Division

Now for the hard part

Indices and ratios based on mean spectralvalues of objects

Relative not absolute values (where possible)

Four spectral ratios/indices used:

NDVI

FDI

R/RE (NIR2+RE)-B

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

19/2319Supervising Scientist Division

Initial segmentation

Conditional quadtree segmentation topdown

Multiscale segmentation based on spectral

variance - NDVI standard deviation

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

20/2320Supervising Scientist Division

All masks applied

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

21/2321Supervising Scientist Division

Radiometric issue Region 1

1st classification

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

22/2322Supervising Scientist Division

Nth classification

8/2/2019 201230 White Side, Tim a Rule-set Driven Approach to Classifying Vegetation From High Spatial Resolution Imagery

23/23

Next steps

Refine classification - eg Region 1 Accuracy assessment

Non-floodplain vegetation

Applying rule-set to 2011 WV-2 data