Extracting Canopies from LiDAR Data and RGBI

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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.

2COPYRIGHT © 2014 The City of Calgary

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


LiDAR Principles


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

LiDAR Principles


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


Point Cloud


Point Cloud


First & Last Returns

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First Return Last Return

COPYRIGHT © 2014 The City of Calgary

Last & Min Returns


RGBi

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


RGBi

• NDVI x 20


Point Cloud x RGBi

• NDVI x 20 x (last-min)


Point Cloud x RGBi

• NDVI x 20 x (last-min)


Shp and cleanup


Shp and cleanup


Canopies


Workbench


Thank You!

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• Questions?

• For more information:• Jairo [email protected] or • Camal [email protected]• The City of Calgary

mailto:[email protected]

mailto:[email protected]

Technology

Extracting Canopies from LiDAR Data and RGBI