Geocarto Tree Monitoring System (GTMS)

Enhances monitoring and management of individual trees

Reveals internal warning signs for arborists to undertake field diagnosis and treatment

Tree Stress Monitoring in Hong Kong

Monitoring tree stress from space using WorldView-2 or WorldView-3 high resolution satellite data

 

 

Time-saving and Cost-effective 

New technology to detect 3 Warning Signs revealed by stressed trees before collapse

New!

We have added the following new charts in the gallery demonstrating our study on stressed trees.

Chart 21   Spectral Reflectance Reveals Tree Stress

Chart 22   Spectral Reflectance Analysis of a Stressed Tree, 2010-2016

Chart 23   Reflectance Analysis Reveals Warning Signs

Chart 24   Warning Signs Revealed by a Stressed Tree

Chart 25   Changes in the Health Condition of a Stressed Tree

Chart 26   Deterioration of a Stressed Tree

Chart 27   What do Stressed Trees reveal before Collapse

Chart 28   What do Stressed Trees reveal before Collapse generated with AComp Data

Chart 29   Collapsed tree in Fanling

Chart 30   Collapsed tree in Berlin

Chart 31    Collapsed tree in Cincinnati

Chart 32   Collapsed tree in Chiswick

Chart 33   Collapsed tree in Düsseldorf

Chart 34   Collapsed tree in Maisons-Alfort

Chart 35   Collapsed tree in Singapore

Chart 36   Collapsed tree in Sydney

Chart 37   Collapsed tree in Whittier

Chart 38   Collapsed tree in Vancouver

Chart 39   Collapsed tree in Singapore

Chart 40   Collapsed tree in Singapore

Chart 41   Removed tree in Lei Yue Mun Park

Chart 42   Stonewall Tree in Forbes Street

Chart 43   A Stressed Tree Before Death

Chart 44   Highly Fluctuating Health Condition Before Collapse

Chart 45   Biotic and Abiotic Factors

Chart 46   Collapsed Tree in Pasadena

Chart 47   Collapsed Tree in Stubbs Road

Introducing WorldView-2 & WorldView-3
Providing satellite data to cover the whole HKSAR in a single pass​

(Image Copyright © DigitalGlobe)

WorldView-2 is the first high-resolution 8-band multispectral commercial satellite. Operating at an altitude of 770 km, WorldView-2 provides data of 40 cm to 50 cm panchromatic resolution and 1.85 m multispectral resolution. The satellite has an average revisit time of 1.1 days and is capable of collecting up to 1 million square km of 8-band imagery per day.

WorldView-3 is the first high resolution super-spectral commercial satellite. Operating at an altitude of 617 km, it provides data of 30 cm panchromatic resolution, 8 bands of 1.24 m multispectral resolution, and 8 additional SWIR (Shortwave Infrared) bands of 7.5 m resolution. The satellite has an average revisit time of less than 1 day and is capable of collecting up to 680,000 square km of 8-band data per day.

Both satellites are able to act like a paintbrush, sweeping back and front to collect very large continuous area of panchromatic imagery of 50 cm to 30 cm resolution and multispectral imagery of 1.85 m to 1.24 m resolution in a single pass. The whole Hong Kong region of 60 km and 60 km can be covered in 5 strips in just one pass.

Spectral Reflectance Analysis

Detects 3 warning signs revealed by stressed trees before collapse caused by biotic and abiotic factors. The warning signs are (1) drop of NIR-1 and NIR-2 reflectances, (2) shift of red edge band to shorter wavelength and (3) reduced absorption in red band.

Stress caused by biotic and  abiotic factors

Revealed by spectral reflectance curves

Healthy Trees

Stressed Trees

1

Drop in NIR-1 and NIR-2 reflectance

Due to degraded leaf cellular structure

NIR

2

Shift of red edge band to shorter wavelength

Due to reduced chlorophyll

Red Edge

3

Reduced absorption in red band

Due to reduced chlorophyll

Red

Case Studies

All the following trees showed the above 3 warning signs before collapse

Tree on steep slope

Tree on stone wall

Tree on level ground

Case 1 - Tree on steep slope

We studied a stressed tree on a steep slope in Lower Albert Road near former Central Government Offices. It collapsed on 20 July, 2015.

 

The spectral reflectance curves in this case were generated from the WorldView-2 data collected on 25 May, 2010 and 17 April, 2015. All 3 warning signs were revealed before its collapse.

2010

2015

Case 2 - Tree on stone wall

We studied a stressed tree on a stone wall in Bonham Road near Centre Street. It collapsed on 22 July, 2015.

 

The spectral reflectance curves in this case were generated from the WorldView-2 data collected on 25 May, 2010 and 17 April, 2015. All 3 warning signs were revealed before its collapse.

2010

2015

Case 3 - Tree on level ground

We studied a stressed tree on level ground in Bonham Road near King's College. It collapsed on 19 April, 2015.

 

The spectral reflectance curves in this case were generated from the WorldView-2 data collected on 25 May, 2010 and 17 April, 2015. All 3 warning signs were revealed before its collapse.

2010

2015

Explore our charts

Chart 1

Chart 1

How is Hong Kong region imaged in one pass?

Chart 2

Chart 2

How are spectral reflectance curves generated?

Chart 3

Chart 3

What are the spectral signatures shown by different materials?

Chart 4

Chart 4

What is the spectral reflectance pattern shown by different tree species?

Chart 5

Chart 5

How is stressed condition revealed?

Chart 6

Chart 6

What is the difference in NIR and SWIR reflectance?

Chart 7

Chart 7

Can WV-2 and WV-3 data be used to monitor the same tree?

Chart 9

Chart 9

Why is there greater difference in red edge reflectance between 2011 and 2014?

Chart 8

Chart 8

What are the warning signs revealed by a tree before collapse?

Chart 10

Chart 10

Which tree shows the greatest variation in NIR reflectance?

Chart 12

Chart 12

What are the warning signs shown?

Chart 11

Chart 11

Which tree shows the least variation in NIR reflectance?

Chart 13

Chart 13

What are the warning signs shown?

Chart 14

Chart 14

What are the warning signs shown?

Chart 15

Chart 15

What are the warning signs shown?

Chart 16

Chart 16

What are the warning signs shown?

Chart 17

Chart 17

Tree in Good Condition

Chart 18

Chart 18

Contrast between Two Trees

Chart 19

Chart 19

What do stressed trees reveal before collapse?

Chart 20

Chart 20

What variations are shown in the spectral reflectance curves of the three trees: 2, 3 and 6?

Chart 21

Chart 21

How does an integrated approach enhance tree monitoring and management?

Chart 22

Chart 22

When did the tree become aggravated?

Chart 23

Chart 23

What warning signs are revealed?

Chart 24

Chart 24

What warning signs are revealed?

Chart 25

Chart 25

What warning signs are revealed?

Chart 26

Chart 26

What warning signs are revealed?

Chart 27

Chart 27

What do Stressed Trees reveal before Collapse

Chart 28

Chart 28

What do Stressed Trees reveal before Collapse generated with AComp Data

Chart 29

Chart 29

Collapsed tree in Fanling

Chart 30

Chart 30

Collapsed tree in Berlin

Chart 31

Chart 31

Collapsed tree in Cincinnati

Chart 32

Chart 32

Collapsed tree in Chiswick

Chart 33

Chart 33

Collapsed tree in Düsseldorf

Chart 34

Chart 34

Collapsed tree in Maisons-Alfort

Chart 35

Chart 35

Collapsed tree in Singapore

Chart 36

Chart 36

Collapsed tree in Sydney

Chart 37

Chart 37

Collapsed tree in Whittier

Chart 38

Chart 38

Collapsed tree in Vancouver

Chart 39

Chart 39

Collapsed tree in Singapore

Chart 40

Chart 40

Collapsed tree in Singapore

Chart 41

Chart 41

Removed tree in Lei Yue Mun Park

Chart 42

Chart 42

Stonewall Tree in Forbes Street

Chart 43

Chart 43

A stressed tree before death

Chart 43a

Chart 43a

Chart 44

Chart 44

Detected highly fluctuating health condition of a tree prior to collapse

Chart 45

Chart 45

Biotic and Abiotic Factors

Chart 46

Chart 46

Collapsed Tree in Pasadena

Chart 47

Chart 47

Collapsed Tree in Stubbs Road

 

Data Cost

(AComp data and "Lossless" pansharpened data)

Satellite

Resolution

Number of Bands

Cost of satellite data per km

Name

WorldView-2

WorldView-3

Company

DigitalGlobe, Inc

Launch Date

2009-10-8

2014-8-13

Coverage

Satellite data of 60km x 60km to cover the whole HKSAR can be acquired in a single pass

Panchromatic

50 cm

30 cm

Multispectral

1.84 m

1.24 m

More than 90 days

US$ 19

Less than 90 days

US$ 24

US$ 29 (8 bands)

US$ 34 (8 bands)

Geocarto is the sole reseller of WorldView-2 & WorldView-3 satellite data in Hong Kong and Macau.

Questions

Questions and answers on Tree Stress Study

Thank you for viewing these tree stress study charts.  They are designed to explain the applications of high resolution satellite remote sensing technology in monitoring tree stress in Hong Kong. The following questions cover the main points presented in the charts.  Can you answer these questions? 

  1. What is the difference in the number of spectral bands between WoldView-2 and WorldView-3 data?

  2. Can WorldView-2 and WorldView-3 data be used together for monitoring the same tree?

  3. What is the main function of hyperspherical direction cosine transformation (HSDC)?

  4. What is the highest spectral reflectance of healthy Chinese banyan (Ficus microcarpa) shown in the charts?

  5. What is the lowest spectral reflectance of stressed Chinese banyan shown in the charts?

  6. What is Red Edge Shift?

  7. Is there a drop in NIR spectral reflectance due to reduction in chlorophyll?

  8. What are the warning signs shown in the spectral reflectance curves of stressed trees before collapse?

View the answers

CONTACT US

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Room 1302, 13/F, Trend Centre,
29-31 Cheung Lee Street,

Chai Wan, Hong Kong

 

Tel.:    (852) 2546 4262
Email:    geocarto@geocarto.com

 

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