extracting canopies from lidar data and rgbi

CONNECT. TRANSFORM. AUTOMATE.

Canopy Extraction Using LiDAR and RGBi

Jairo CastilloData Analyst (The City of Calgary)

Camal DharamdialLead, Business Development & Innovation (The City of Calgary)

Canopy Cover - Why

• The Municipal Development Plan (MDP) and Calgary Transportation Plan (CTP) approved by Council has Canopy Coverage as one of the Fourteen indicators of Watershed Health.

• Council expectation is to increase metric percent of tree canopy to 14-20% in 60 years

• The best report we have is from UFORE metrics – 1998 – 7.2% of Canopy.

• We need to validate this and set a baseline in 2014.

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ProcessWhy use LiDAR and Imagery?• LiDAR maps through canopy• LiDAR is independent of sun angle • LiDAR can be collected, day or night• Our process will use is RGBi combined with LiDAR

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LiDAR Principles

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• Range = (travel time * speed of light) / 2.0• Range + pointing direction + GNSS + IMU XYZ

LiDAR Principles

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Outgoing laser pulse One or more return pulses Intensity of each return pulse

Outgoing laser pulse

First return

Second return

Third return

Fourth return

Bookmarks

• Point Cloud• First and Last Returns• RGBi• Point Cloud x RGBi• Shp polygons and Cleanup

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Point Cloud

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Point Cloud

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First & Last Returns

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First Return Last Return

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Last & Min Returns

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RGBi

• Decompose RGBi• NDVI=(nir-red)/(nir+red)

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RGBi

• NDVI x 20

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Point Cloud x RGBi

• NDVI x 20 x (last-min)

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Point Cloud x RGBi

• NDVI x 20 x (last-min)

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Shp and cleanup

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Shp and cleanup

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Canopies

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Workbench

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Thank You!

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• Questions?

• For more information:• Jairo jairo.castillo@calgary.ca or • Camal camal.dharamdial@calgary.ca• The City of Calgary