airborne laser scanning (als) data processing and its usage for forest cover and forest stand...
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Airborne Laser Scanning (ALS) data processing and its usage for forest cover and forest stand parameter estimation
Géza Király1, Gábor Brolly1
1University of West Hungary Faculty of ForestryDepartment of Surveying and Remote SensingH-9400 SOPRON, Bajcsy-Zs u. 4.
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Methodology 1.
Planning the survey and getting the permissionExecution of the surveyPre-processingFilteringRelative orientationAbsolute orientation
ProcessingDigital Surface Model (DSM)Digital Terrain Model (DTM)normalised Digital Surface Model (nDSM)
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Methodology 2.
Forest parameters extractionArea-based methodsStand heightsCrown closureStem density
Individual tree based methodsNumber of single treesSingle tree heightsCrown projection area
Processing of imagery data
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INMEIN project (HUSK/1101/1.2.1/0141)Execution of the survey: 2013.09.08.
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File (‚Adatlap’) – MH GEOSZ
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ExecutionPoint density (0 – 40 points/m2)
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• ~1900 images have been captured parallel
• True-colour images (RGB)
• ~10 cm resolution• Mono- and stereo-
photogrammetric evaluation
Image-based forest cover
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Relative orientation
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Digital Elevation ModelsDigital Terrain ModelDTM
Normalised Digital Surface Model – nDSM
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Adaptive TIN method
nDSM = DSM-DTM
Digital Surface ModelDSM
Fitting parabola method
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Digital Surface Model (DSM)
Functional model Tree height Single crowns Semi-continuous surface
Properties Highest points of the crowns Smooth surfaces inside the crowns Drop down to the ground between the crowns
Polynomial Approximation Approximation Local point filtering Maximum 2nd order surfaces
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Digital Terrain Model (DTM)
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Normalised Digital Surface Model (nDSM) and its detail
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Normalised Digital Surface Model, Canopy Height Model (nDSM – CHM)
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𝑛𝐷𝑆𝑀=𝐷𝑆𝑀−𝐷𝑇𝑀
HGFV cc
where:V: Volume of the stand (m3)Fc: form number for crown projection areaGc: Sum of crown projection area (m2)H: average stand height (m)
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Segmentation of the crownsInverse watershed
modelling Jenson and Domingue 1988Gougeon 1995Hyyppä, Inkinen 1999
Sinkpoints -> tipWatershed -> crown
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ResultsForest stand heightDistribution of the relative
heights of the points90% perc:29.25 m (39 m/34 m)
Delineation of sub-stands
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ResultsCrown-closure
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0.00 20.00 40.00 60.00 80.00 100.000
20
40
60
80
100
120
Z (üzemterv)
Z (üzemterv)
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ResultsDelineation of sub-stands
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ResultsNumber of treesOld stand:383 (227)
Reforestation:582 (100)
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ResultsVolume
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Reference measurements2014.04.03Kisbodak18P19C19E
National Forest Inventory method
Terrestrial Laser ScanningField Survey (ERTI)
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Further tasks
Reference data collection and processingForm-number determination for poplar standsCombination of Laser Scanning data with imagery data for improving automatic forest cover maps and forest parameters determination
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THANKS FOR YOUR ATTENTION!Further info: [email protected]
Acknowledgements:
INMEIN - HUSK/1101/1.2.1/0141
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