Processing LiDAR data:

Fusion tutorial

Douglas Bolton Rory Tooke

Nicholas Coops

University of British Columbia

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• Open/Visualize LiDAR data in Fusion

• Derive surface products (2 m) - Digital elevation model (DEM)

- Digital surface model (DSM)

- Canopy height model (CHM)

• Extract LiDAR data for polygons and plots - Calculate LiDAR metrics for plots

• Calculate gridded LiDAR metrics - Apply existing models in ArcGIS to derive biomass, volume, etc. from

gridded metrics

• Learn to work with multiple LiDAR tiles

Tutorial Objectives

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LiDAR data used in this tutorial

Discrete return LiDAR data collected in 2010 over the Malcolm Knapp Research Forest

- Collected by McElhanney Consulting Services Ltd using a ALS50-II Leica system

- Average of 3.1 pulses/m2

- Multiple returns per pulse

- Aerial photos were collected on the same flight

Malcolm Knapp Research Forest - UBC Research Forest

- Located in the Coast Western Hemlock biogeoclimatic subzone near Maple Ridge, BC

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• Open/Visualize LiDAR data in Fusion

• Derive surface products (2 m) - Digital elevation model (DEM)

- Digital surface model (DSM)

- Canopy height model (CHM)

• Extract LiDAR data for polygons and plots - Calculate LiDAR metrics for plots

• Calculate gridded LiDAR metrics - Apply existing models in ArcGIS to derive biomass, volume, etc. from

gridded metrics

• Learn to work with multiple LiDAR tiles

Tutorial Objectives

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Step 1: Extract probable ground returns (Groundfilter)

Step 2: Create surface from ground returns (GridSurfaceCreate)

Lidar visualizations produced with FUSION/LDA software – USDA Forest Service

Digital Elevation Model (DEM)

6 6 Lidar visualizations produced with FUSION/LDA software – USDA Forest Service

Digital Surface Model (DSM)

Create a digital surface model (CanopyModel)

7 7 Lidar visualizations produced with FUSION/LDA software – USDA Forest Service

Digital Surface Model (DSM)

Create a digital surface model (CanopyModel)

8 8 Lidar visualizations produced with FUSION/LDA software – USDA Forest Service

Digital Surface Model (DSM)

Create a digital surface model (CanopyModel)

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Visualization for

Malcolm Knapp Research Forest

Digital Surface Model (DSM)

Create a digital surface model (CanopyModel)

10 Lidar visualizations produced with FUSION/LDA software – USDA Forest Service

Digital Surface Model (DSM)

Create a digital surface model (CanopyModel)

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Height (m)

Point

elevation

Surface

elevation

Point

height above

surface

Lidar visualizations produced with FUSION/LDA software – USDA Forest Service

Canopy Height Model (CHM)

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Height (m)

Lidar visualizations produced with FUSION/LDA software – USDA Forest Service

33.0 m 35.9 m

34.4 m 35.6 m 40.7 m

34.8 m

Canopy Height Model (CHM)

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Lidar Point Cloud for Alex Fraser Research Forest

Lidar visualizations produced with FUSION/LDA software – USDA Forest Service

Plot level analysis

Extract LiDAR data for plots (Clipdata)

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Lidar Point Cloud for Alex Fraser Research Forest

Plot level analysis

Extract LiDAR data for plots (Clipdata)

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High Volume Site Low Volume Site

Hei

ght

(m)

86% 16%

Calculate Cover Metrics

Cover Above 2 m

Calculating Lidar metrics

Calculate metrics (Cloudmetrics)

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High Volume Site Low Volume Site

Hei

ght

(m)

27 m 15.6 m

Calculate Height Metrics

Mean Height

Calculating Lidar metrics

Calculate metrics (Cloudmetrics)

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High Volume Site Low Volume Site

Hei

ght

(m)

30 m 21 m

Calculate Height Metrics

75th Percentile

Calculating Lidar metrics

Calculate metrics (Cloudmetrics)

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High Volume Site Low Volume Site

Hei

ght

(m)

33.5 m 29 m

Calculate Height Metrics

95th Percentile

Calculating Lidar metrics

Calculate metrics (Cloudmetrics)

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High Volume Site Low Volume Site

Hei

ght

(m)

0.19 m 0.50 m

Coefficient of Variation

Measure of the structural diversity

Calculating Lidar metrics

Calculate metrics (Cloudmetrics)

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Plot Level Analysis

Forest Attributes Gross Stem Volume Basal Area Mean height Dominant height Loreys height Wood biomass Bark biomass Stem biomass Foliage biomass Branches biomass Crown biomass Total above-ground biomass

Lidar Metrics 75th height percentile 95th height percentile Mean Standard deviation Coefficient of variation Cover above 2 meters

Linear model

Forest Attribute = exp(b0 + b1ln(x1) + b2ln(x2)…bnln(xn)

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Calculating Gross Stem Volume

Step 1: Calculate gridded metrics

Step 2: Apply Statistical model

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Model form we often use:

Attribute = exp(b0 + b1ln(x1) + b2ln(x2) + …bnln(xn)) X BCF

Model to derive net volume (m3/ha) for Malcolm Knapp

Net Volume =

exp(-33.6579 + (2.0058 * Ln("Elevation_P95.asc")) + (7.1162 * Ln("Elevation_Cover_at_2m.asc"))) * 1.0872

Example model to apply