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Spatial tools for LiDAR based watershed management and forestry analysis
1. Spatial tools for LiDAR
based watershed
management and forestry
analysis
Antonello Andrea, Franceschi Silvia,
Tonon Giustino and Comiti Francesco
FOSS4G-EU Como 16 July 2015
2. WHO AM I?
● co-founder of HydroloGIS with Andrea Antonello
● environmental engineer specialized in hydrology,
hydraulics and geomorphology
● PhD student of Science and Technology at the Free
University of Bolzano (Italy)
● developed scientific models contained in the
JGrassTools library in the field of:
– hydrology
– hydraulics
– forestry
● OSGeo Charter Member
3. JGRASSTOOLS
● geospatial library containing modules for:
– vector and raster processing
– geomorphology
– forestry
– mobile mapping connection
● it is the core behind the Spatial Toolbox of uDig GIS
● it can be used stand alone using the application
Stage (http://bit.ly/stage_downloads): Spatial
Toolbox And Geoscripting Ennvironment tool for
environmental modelling
10. WHAT IS LESTO?
● Open Source
● GIS aware
● library dedicated to
● sciences that make use of
● LiDAR data
Developed and maintained by HydroloGIS and the
team of prof. Tonon at the Faculty of Science and
Technology of the Free University of Bolzano (Italy).
Contains tools for handling high resolution LiDAR data
(LAS) and for LiDAR analysis related to forestry.
16. PREPROCESSING
Packaging including the available pre-processing operations
are:
● Utilities
– LasIndexer: creates indexes for LAS files
– LasInfo: prints out information of a LAS file/folder
18. PREPROCESSING
Packaging including the available pre-processing operations
are:
● Utilities
– LasIndexer: creates indexes for LAS files
– LasInfo: prints out information of a LAS file/folder
– LasOverviewCreator: creates a shp with overview
20. PREPROCESSING
Packaging including the available pre-processing operations
are:
● Utilities
– LasIndexer: creates indexes for LAS files
– LasInfo: prints out information of a LAS file/folder
– LasOverviewCreator: creates a shp with overview
– LasPointDensityExtractor: creates a shp with point
cloud density on a given grid
22. PREPROCESSING
Packaging including the available pre-processing operations
are:
● Utilities
– LasIndexer
– LasInfo
– LasOverviewCreator
– LasPointDensityExtractor
● Filter
– LasHeightDistribution: analyze the height distribution
and categorize the forest type
25. PREPROCESSING
Packaging including the available pre-processing operations
are:
● Utilities
– LasIndexer
– LasInfo
– LasOverviewCreator
– LasPointDensityExtractor
● Filter
– LasHeightDistribution
– LasHistogram: creates an histogram of the elevation
or intensity of all the points in the LAS file
28. PREPROCESSING
Packaging including the available pre-processing operations
are:
● Utilities
– LasIndexer
– LasInfo
– LasOverviewCreator
– LasPointDensityExtractor
● Filter
– LasHeightDistribution
– LasHistogram
– LasMerger: merges all the LAS file contained in a folder
in a single one
29. PREPROCESSING
Packaging including the available pre-processing operations
are:
● Utilities
– LasIndexer
– LasInfo
– LasOverviewCreator
– LasPointDensityExtractor
● Filter
– LasHeightDistribution
– LasHistogram
– LasMerger
– LasThresholder: extracts the points with values interval
30. RASTER
Raster package contains all the available modules to
interpolate and create a raster (DTM, DSM) from raw point
cloud. The different interpolation algorithms are
● AdaptiveTinFilter: the implementation of the adaptive TIN
method of Axelsons
● Las2BivariateRasterMosaic: uses the bivariate function to
interpolate a raster from the point cloud and creates a
mosaic of TIF
● Las2RasterInterpolator: interpolates a raster from LAS
points using the Inverse Distance Weight method
● LasOnRasterMapper: creates a raster by mapping max/min
elevation point in each pixel
● LasTriangulation2Dsm: creates a DSM from the
triangulation of the point cloud
34. BUILDINGS
This package contains a module to extract the vector data of
the buildings from a LAS file.
● LasOnDtmBuildingExtractor: based on the identification
of the holes in the ground generated by cutting all the
points with an elevation on the ground over a given
threshold
● the output shapefile can be cleaned from noise data and
smoothed on the boundaries
37. FLIGHTLINES
Modules to separate different flightlines inside a LAS file:
● FlightLinesExtractor: creates different las files for each of
the different flightlines inside the single las
● FlightLinesIntensityNormalizer: normalize intensity values
between different flightlines considering the position of
the aircraft (x,y,z)
39. VEGETATION
Extrapolation of the whole forest biometric data (e.g.
forest biomass) can be obtained through two
approaches:
● area-based approaches (AB): forest attributes are
estimated by relating plot data to ALS data by
statistically procedure
● individual tree crown (ITC) approaches: ITC
approaches can use both raster CHM and point ALS
data and are aimed to detect position and main
characteristics of each single tree. Single-tree
records can then be aggregated at plot, forest,
watershed or regional scale.
40. VEGETATION
Extrapolation of the whole forest biometric data (e.g.
forest biomass) can be obtained through two
approaches:
● area-based approaches (AB): forest attributes are
estimated by relating plot data to ALS data by
statistically procedure
● individual tree crown (ITC) approaches: ITC
approaches can use both raster CHM and point ALS
data and are aimed to detect position and main
characteristics of each single tree. Single-tree
records can then be aggregated at plot, forest,
watershed or regional scale.
41. VEGETATION MODULES
The available modules for single tree extraction are
based on the identification of local maxima:
● RasterMaximaFinder: identifies local maxima on
raster input data
47. VEGETATION MODULES
The available modules for single tree extraction are
based on the identification of local maxima:
● RasterMaximaFinder: identifies local maxima on
raster input data
● PointCluodMaximaFinder: identifies local maxima on
point cloud input data
51. VEGETATION MODULES
The available modules for single tree extraction are
based on the identification of local maxima:
● RasterMaximaFinder: identifies local maxima on
raster input data
● PointCluodMaximaFinder: identifies local maxima on
point cloud input data
● WatershedAlgorithm: delineates the crowns of the
trees based on raster data
54. DATA VISUALIZATION TOOLS
● profiles of the LAS data considering 4 main directions
● position of the measured trees
● position of the extracted trees with highlighted the
type of the tree: true positive, false positive
58. APPLICATION: STUDY AREA
high local variety in
forest structure
AURINA VALLEY
VEGETATION:
●Norway spruce (Picea abies)
●Larch (Larix decidua)
●Stone pine (Pinus cembra)
AREA = 10 km2
65. WATERSHEAD MANAGEMENT
● GIS-based tool for predicting the magnitude of LW
transport during flood events at any given section
within a river basin
● two main processes related to wood debris:
– LW recruitment from hillslopes
– LW transport/propagation along the network
66. SHALSTAB
model
Unstable slopes connected
to fluvial network
CONNECTIVITY
model
AREAS THAT
PROVIDES LW
Channel
widening
Slope
instability
EXTREME EVENTS
INPUTS AND PROCESSES OUTPUTSLEGEND
LW TRANSPORT DURING FLOODS
67. SHALSTAB
model
Unstable slopes connected
to fluvial network
CONNECTIVITY
model
AREAS THAT
PROVIDES LW
TREE HEIGHT AND
FOREST STAND VOLUME
CHM and
semi-empirical model
Channel
widening
Slope
instability
EXTREME EVENTS
INPUTS AND PROCESSES OUTPUTSLEGEND
LW TRANSPORT DURING FLOODS
68. LW TRANSPORT DURING FLOODS
SHALSTAB
model
Unstable slopes connected
to fluvial network
CONNECTIVITY
model
AREAS THAT
PROVIDES LW
TREE HEIGHT AND
FOREST STAND VOLUME
CHM and
semi-empirical model
CRITICAL SECTIONS
AND LW VOLUME
Channel
widening
Slope
instability
EXTREME EVENTS
INPUTS AND PROCESSES OUTPUTSLEGEND
Volume and dimensions
of available LW
LW propagation
Field data
monitoring LW transport
70. JGRASSTOOLS: INPUT
● digital models of the terrain and vegetation: DTM,
DSM, FSV
● DTM derived geomorphology attributes: TCA,
slope, connectivity, watershed delineation
● extension of the bankfull area: area covered by
water during standard flow conditions
● position and dimensions of bridges and dams: field
survey or available cadaster
● superficial geology: rock and deposits (erodible)
72. LW PROPAGATION
● identifies the critical section for the transit of LW in
the given stream network
● based on the comparison between the length of the
logs and channel width
74. ● finalize the implementation of a Particle Swarming
Optimizer for automatic calibration of the models
● improve the propagation algorithm to consider also the
height of the water in the rivers
● connect the results of the elaboration of LiDAR data for
the evaluation of the volume, height and diameter of the
logs in each section
FUTURE PLANS