lidar 2018 tree canopy density and height analysis - houston-galveston area...
TRANSCRIPT
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Lidar 2018Tree Canopy Density and Height Analysis
Qian Song
HARC
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Data: 2014 TCEQ
LAS Point Classification
1 Processed, but unclassified
2 Bare-earth Ground
3 Low Vegetation (0.01m to 1.00m)
4 Medium Vegetation (1.01m to 3.00m)
6 Building
7 Low Point (noise)
9 Water
10 Ignored Ground
14 Culverts
17 Bridge Decks
5 High Vegetation (greater than 3.01m)
Image: https://environment.arlingtonva.us
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Tree CanopyDensity
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Tree Density - Methodology
1. Divide the study area into many small equal-sized units (Raster Dataset)
2. In each raster cell,
Density =The Number of Above Ground Points
The Total Number of Points
Tree Canopy Density =The Number of High Vegetation Points
The Number of High Vegetation Points + The Ground Points
![Page 5: Lidar 2018 Tree Canopy Density and Height Analysis - Houston-Galveston Area …h-gac.com/geographic-data-workgroup/documents/gdw-HARC... · 2019-11-04 · Height Analysis Qian Song](https://reader034.vdocument.in/reader034/viewer/2022042407/5f216b2fd4549020855bd055/html5/thumbnails/5.jpg)
Tree Density - Workflow
Las DatasetTree Canopy
Density Raster
Total Points Raster
Above Ground Points Raster
Las Point Statistics As Raster (Point Count)
Divide
Tips
• Convert any resulting NoData cells to 0
• Make sure one raster to be floating point to get floating-point output
Las Dataset Layer(Total)
Las Dataset Layer(Above Ground)
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Tree Density - Results
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Tree Density - Results
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Tree CanopyHeight
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Tree Height - Methodology
Digital Surface Model(DSM): the first return surface
First return of the High Vegetation Class
Digital Elevation Model(DEM): the bare earth surface
Canopy Height = DSM - DEM
![Page 10: Lidar 2018 Tree Canopy Density and Height Analysis - Houston-Galveston Area …h-gac.com/geographic-data-workgroup/documents/gdw-HARC... · 2019-11-04 · Height Analysis Qian Song](https://reader034.vdocument.in/reader034/viewer/2022042407/5f216b2fd4549020855bd055/html5/thumbnails/10.jpg)
Tree Height - Workflow
Las Dataset
Las Dataset to Raster DSM
DEM
Minus Tree Height
Las Dataset Layer(Above Ground &
First Return)
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Tree Height - Results
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Tree Height - Results
![Page 13: Lidar 2018 Tree Canopy Density and Height Analysis - Houston-Galveston Area …h-gac.com/geographic-data-workgroup/documents/gdw-HARC... · 2019-11-04 · Height Analysis Qian Song](https://reader034.vdocument.in/reader034/viewer/2022042407/5f216b2fd4549020855bd055/html5/thumbnails/13.jpg)
Houston Advanced Research Center (HARC)
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Wrap Up
• Tree Canopy Density and Height Processes and Results
• Other applications
– Flood Inundation Depth and Area
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Qian [email protected]
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