Download pdf - 2013 ASPRS Track, Monitoring Ponderosa Pine Health Using Satellite Imagery by Kathleen Johnson

DigitalGlobe Proprietary and Business Confidential

Monitoring Ponderosa Pine Health Using Satellite Imagery


DigitalGlobe 2

• Kathleen Johnson*

• Greg Hammann

• Rachana Ravi

*[email protected]

• Keith Bol

• Barbara Morey

Monitoring Ponderosa Pine Health Using Satellite Imagery

Team Participants:


Goals & Objectives

3

• To Demonstrate the capabilities of WV02 8-bands for vegetation health/stress assessments

• Document the extent of tree stress from 2010 through 2013 in the White Ranch Park Area, using satellite imagery.

• Test Case for DG classification system applied to vegetative health studies

• Look for evidence of new Mountain Pine Beetle Activity

DigitalGlobe


4

World View-2

DigitalGlobe

TABLE 1: WorldView -2 Bands

Band

#

Name Wavelength

(nm)

1 Coastal 400-450

2 Blue 450-510

3 Green 510-580

4 Yellow 585-625

5 Red 630-690

6 Red Edge 705-745

7 NIR1 770-895

8 NIR2 860-1040

PAN Panchromatic 450-800


Jefferson County Preliminary Study: Elk Meadow Park

5 DigitalGlobe


Elk Meadow: Dwarf Mistletoe Damage

6

False Color: Healthy Trees are Bright Red

Natural Color: Damage is Visible

DigitalGlobe

JUNE 2010 JUNE 2012


Jefferson County Research Site: White Ranch Park

7 DigitalGlobe


Ground Truth Assumptions:

8

•Ground Truth for Dwarf Mistletoe acquired December 2010 (Rawhide and Sawmill Ridges)

• Treatment for mistletoe control started after ground truth acquisition (Spring 2011-Present)

•Mountain Pine Beetle was discovered during the Winter Survey in 2010, and treatment began at that time.

DigitalGlobe


White Ranch Park: Ground Truth

9 DigitalGlobe


Parasites:

10

Dwarf Mistletoe (Arceuthobium vaginatum)

Mountain Pine Beetle (Dendroctonus ponderosae)

DigitalGlobe


Pre-Processing:

11

• Imagery Selection (4): - 10JUNE24, 11AUGUST23, 12MAY24, 13AUGUST14

•Bundle Adjustment -Orthorectification (30 m DEM)

-Co-registration

•Atmospheric Correction (DG-ACOMP)

DigitalGlobe


12

Normalized Difference Vegetation Index (NDVI)

NDVI = (rNIR – rRED)/(rNIR + rRED) Brightness = Health

Vegetative Indices

DigitalGlobe

TABLE 4. Summary of Vegetative Indices applied to the JCOS Forestry Problem

Index Formula Bands Reference

Normalized Difference

Vegetative Index NIR1 NDVI-1

(NIR1 - Red)/(NIR1 + Red)

7-5 Rouse et al. (1974)

Shamsodinni et al. (2010)

Normalized Difference

Vegetative Index NIR2 NDVI-2

(NIR2 - Red)/(NIR2 + Red)

8-5 Rouse et al. (1974)

Shamsodinni et al. (2010)

Red Edge NDVI (Red Edge - Red)/(Red Edge + Red) 6-5 Filchev (2010)


13

JUNE 2010 AUGUST 2013 CHANGE

NDVI Results & Change Detection

DigitalGlobe

Table 7. Change Detection Color Codes

BLUE Negative Change:

YELLOW Neutral/Positive Change:


Classification Model:

14

•DG Classification-Supervised

•Decision Tree Classifiers: • Robust to outliers

• Applies the same rule at each Node

• Compares well to Non-linear Classifiers

• Random Forest – Ensemble Tree Method • (Random Forest: Breiman 2001)

•Use WEKA Scorer to Evaluate Models • http://www.cs.waikato.ac.nz/ml/weka/

DigitalGlobe


Random Forest – 20 Trees:

15

•A stable model builder with little data preprocessing

•Does not require a normal distribution

• Relies upon balanced class sample size

• Ensemble decision tree method (employs multiple trees)

•Most robust decision tree method for outliers

• Competitive with nonlinear classifiers such as neural networks

DigitalGlobe


16

Classification Results: Accuracy and Precision

DigitalGlobe

Imagery Accuracy Kappa Statistic

10JUNE24 93.17 0.92

11AUG23 93.47 0.92

12MAY24 93.88 0.93

13AUG14 89.69 0.88

95% Confidence Interval


Ponderosa Health: Random Forest-20

17

10JUNE24 11AUGUST23

DigitalGlobe

Table 8. Classification Codes

ORANGE Unhealthy/Stressed

GREEN Healthy

Yellow-Green Broadleaf

12MAY24 13AUGUST14



18

10JUNE24 11AUGUST23

DigitalGlobe



GREEN Healthy




19

12MAY24 13AUGUST14

DigitalGlobe



GREEN Healthy



Ponderosa Health: Pine Beetle Treatment

20

10JUNE24 11AUGUST23

DigitalGlobe



GREEN Healthy



Ponderosa Health: Pine Beetle Treatment

21

12MAY24 13AUGUST14

DigitalGlobe



GREEN Healthy



DigitalGlobe 22

Summary of Classification Results

10JUNE24 11AUGUST23 12MAY241 3AUGUST14


Conclusions:

23

• Ponderosa Pines within White Ranch Park have shown signs of accumulated stress: - Mistletoe,

- Pine Beetle

- Drought (Fa11 2011-Spring 2013)

- Tree stress was severe enough to be visible in natural color imagery in many instances.

- Through time, the total number of trees has been reduced by remediation activities

• DG Classification results were more reliable than NDVI Change Detection: - Performed at > 90% accuracy except in the case of the 2013, where some of

the ground truth had been removed by mistletoe remediation.

DigitalGlobe


Conclusions:

24

• This Study lays the foundation for continuing forestry studies across the Foot Hills region, using satellite imagery:

- Identify additional areas to be examined for mistletoe infestation and

remediation

- Can identify potential Pine Beetle attacks early IF we can capture imagery during the proper stages of the Life Cycle (need March snow free imagery)

DigitalGlobe


Acknowledgments:

25

• JCOS: Keith Bol, Barbara Morey

• Project Sponsor: Kumar Navulur, NGP Director

• My Manager: Giovanni Marchisio, Data Mining Director

• DG Classification Training: Rachana Ravi, Kris Koperski

• Data Pre-Processing: Chuck Chaapel, Donnie Marino

DigitalGlobe


Thank You Questions/Discussion