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Copernicus EU
Copernicus EU www.copernicus.eu
Copernicus EU
Copernicus Training and Information Session
10 and 11 may 2017 in Lund, Sweden
Green areas: numerous positive effects for sustainable metropolisSatellite images : an easy way to map vegetation
Dominique HEBRARD
Land Monitoring
Urban Heat Island
“Through the Urban Agenda for the EU, national governments, the European Commission, European institutions and other stakeholders will be working together for a sustainable, innovative and economically powerful Europe that offers a good quality of life.”http://urbanagendaforthe.eu
The green areas contribute of the quality of life for urban inhabitants.
Urban Agenda for the EU
Urban Agenda for the UE
U r b a n a g e n d a f o r t h e E U
Land Monitoring
The followings positive effects should be taken into account :
Green areas benefits are numerous
- limitation of floods- biodiversity conservation policies- inhabitant well-being and positive impacts on health- urban quality- cooling effect (urban heat island)
B e n e fi t s o f g r e e n a r e a s a r e n u m e r o u s
Land Monitoring
The Urban vegetation is usually not well known in the current database especially in the private areas. It’s an important lack of data for the public policies makers who need Inventory of the situation of their metropolis. They need also data to asses the efficiency of the strategies implemented.
K n o w l e d g e o f g r e e n a r e a s f o r u r b a n p l a n n e r s
Land Monitoring
Most of the optical earth observation satellites have sensors that are able to map the vegetation.
How satellite images can contributeto the knowledge of green areas ?
Vegetation is characterized by
- high absorbtion on the red - low absorption on Near Infrared.
H o w s a t e l l i t e d a t a c a n c o n t r i b u t e t o t h e k n o w l e d g e o f g r e e n a r e a s ?
Land Monitoring
A simple vegetation indicator called NDVI (Normalized Difference Vegetation Index) enables to map in a simple way the vegetation.
NIR : Near Infra-Red bandRED : Red Band
NDVI = NIR - REDNIR + RED
J. W. Rouse. “Monitoring the vernal advancement and retrogradation of natural vegetation,”Type ii report, NASA/GSFCT, Greenbelt, MD, USA, 1973. 12.1.1
lRVI (Ratio Vegetation Index) l RVI = NIR / RED
lDVI (Difference Vegetation Index) DVI = NIR - RED
l…..
Other vegetation index combining RED and NIR exist as :
H o w s a t e l l i t e d a t a c a n c o n t r i b u t e t o t h e k n o w l e d g e o f g r e e n a r e a s ?
Land Monitoring Of course channels red and infra-red are needed, but the resolution is
also a key issue.
Very High Resolution images are the best solution to map the vegetation, especially at the cadastral parcel level. - Pleiades (50 cm) fit to this need for urban areas- Sentinel 2 have a lower resolution (10 m). This lower resolution can fit for rural green areas and monitoring land consumption. Sentinel 2 are easy to get and it’s possible to choose easily the best season.
The season for the selected image has to be adpated, depending on the local climate. (eg: in France it should be good to select an image between march and september)
W h i c h i m a g e a r e r e l e v a n t f o r g r e e n a r e a s ?
Land Monitoring
Copernicus sources for Vegetation mapping
Satellite data•Copernicus Contributing MissionsOptical missions with NIR and Red bands as Pléiades with Very High Resolution for urban areas, or RapidEye, SPOT with High Resolution ...
•Sentinel-2 missionFull constellation will provide image with NIR (band8) and RED (band4) about every day at 10-20m spatial resolution
Copernicus Land Monitoring servicesCopernicus Global Land Service provides access to Pan-european High Resolution Layers of Forests and grassland maps from 20m resolution satellite imagery updated every 3 years.
Copernicus sources for Green Areas
Land Monitoring
Using satellite data to map green areas
DEMONSTRATION
Use of very high resolution optical satellite data to have a global view of Green areas in urban context.
Land Monitoring
Demonstration
Data used:Pléiades image acquired the 05-MAR-2014, orthorectified
Software used for the demo:
Qgis software is usedFree and Open Source Geographic Information System
Sentinel Application Platform (SNAP) Free Toolboxes made available by ESA
can be used for similar manipulation with Sentinel2
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Demonstration
> Open satellite dataDemonstration
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Demonstration> Adapt radiometric parameters to see the landscape in true colors
Demonstration
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Demonstration> Adapt radiometric parameters to see the landscape in true colors
Demonstration
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> Zoom in the area of interestDemonstration
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> NDVI computationDemonstration
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> NDVI computation
=NDVI=(PIR-R)/(PIR+R)
Demonstration
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> NDVI computationDemonstration
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> Vegetation extractionDemonstration
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> Vegetation layerDemonstration
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> Vegetation layer : create a mask of vegetation
Mask=1 if NDVI>0.3
Demonstration
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> Vegetation vector layerDemonstration
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> Vegetation vector layerDemonstration
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> Vegetation vector layerDemonstration
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> Vegetation vector layerDemonstration
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> Vegetation vector layerDemonstration
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> Vegetation vector layerDemonstration
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> Vegetation area estimationDemonstration
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> Vegetation area estimationDemonstration
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Outlook : a step towards more sophisticated products Contribution of Pléiades-HR images to the assessment of urban green infrastructures : dealing with urban ecological network issues and urban densification
Source : Pauline Crombette (LISST CIEU, CNES)
roughness coefficientVegetation : trees
Increase of the roughness ceof. Depending on the buidings and roads
Area with vegetation trees
ecological network
