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24.1.14. Point Cloud Extraction

Informacja

These algorithms are only available if QGIS uses the PDAL library version 2.5.0 or newer.

24.1.14.1. Granica

Exports a polygon file containing point cloud layer boundary. It may contain holes and it may be a multi-part polygon.

../../../../_images/point_cloud_boundary.png

Rys. 24.16 Extracting high vegetation and building polygons from an input point cloud layer

Parametry

Parametry podstawowe

Etykieta

Nazwa

Typ

Opis

Warstwa wejściowa

INPUT

[point cloud]

Input point cloud layer to calculate boundary for

Resolution of cells used to calculate boundary

Opcjonalne

RESOLUTION

[numeric: double]

Resolution of cells used to calculate boundary

Minimal number of points in a cell to consider cell occupied

Opcjonalne

THRESHOLD

[numeric: integer]

Minimal number of points in a cell to consider cell occupied

Granica

OUTPUT

[vector: polygon]

Domyślnie: [Zapisz do pliku tymczasowego]

Specify the point cloud file to use as output. One of:

  • Zapisz do pliku tymczasowego

  • Zapisz do pliku…

Parametry zaawansowane

Etykieta

Nazwa

Typ

Opis

Filter expression

Opcjonalne

FILTER_EXPRESSION

[wyrażenie]

A PDAL expression for selecting a subset of features in the point cloud data

Cropping extent

Opcjonalne

FILTER_EXTENT

[zasięg]

A map extent for selecting a subset of features in the point cloud data

Available methods are:

  • Calculate from layer…: uses extent of a layer loaded in the current project

  • Calculate from layout map…: uses extent of a layout map item in the active project

  • Calculate from bookmark…: uses extent of a saved bookmark

  • Use map canvas extent

  • Draw on canvas: click and drag a rectangle delimiting the area to take into account

  • Enter the coordinates as xmin, xmax, ymin, ymax

Wyniki

Etykieta

Nazwa

Typ

Opis

Granica

OUTPUT

[vector: polygon]

Output polygon vector layer with the point cloud boundary. Currently supported format is .GPKG.

Kod pythona

ID algorytmu: pdal:boundary

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.1.14.2. Gęstość

Exports a raster file based on the number of points within each raster cell - useful for quality checking of point cloud datasets.

../../../../_images/point_cloud_density.png

Rys. 24.17 Point density (number of points per 2x2 m) as a raster

Parametry

Parametry podstawowe

Etykieta

Nazwa

Typ

Opis

Warstwa wejściowa

INPUT

[point cloud]

Input point cloud layer to export

Resolution of the density raster

RESOLUTION

[numeric: double]

Domyślnie: 1.0

Cell size of the output raster

Tile size for parallel runs

TILE_SIZE

[numeric: integer]

Domyślnie: 1000

Size of the tiles to split the data into for parallel runs

Gęstość

OUTPUT

[raster]

Domyślnie: [Zapisz do pliku tymczasowego]

Specify the raster file to export the data to. One of:

  • Zapisz do pliku tymczasowego

  • Zapisz do pliku…

Parametry zaawansowane

Etykieta

Nazwa

Typ

Opis

Filter expression

Opcjonalne

FILTER_EXPRESSION

[wyrażenie]

A PDAL expression for selecting a subset of features in the point cloud data

Cropping extent

Opcjonalne

FILTER_EXTENT

[zasięg]

A map extent for selecting a subset of features in the point cloud data

Available methods are:

  • Calculate from layer…: uses extent of a layer loaded in the current project

  • Calculate from layout map…: uses extent of a layout map item in the active project

  • Calculate from bookmark…: uses extent of a saved bookmark

  • Use map canvas extent

  • Draw on canvas: click and drag a rectangle delimiting the area to take into account

  • Enter the coordinates as xmin, xmax, ymin, ymax

X origin of a tile for parallel runs

Opcjonalne

ORIGIN_X

[numeric: double]

Y origin of a tile for parallel runs

Opcjonalne

ORIGIN_Y

[numeric: double]

Wyniki

Etykieta

Nazwa

Typ

Opis

Gęstość

OUTPUT

[raster]

Output raster layer with number of points within each cell. Currently supported format is .TIF.

Kod pythona

ID algorytmu: pdal:density

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.1.14.3. Filtr

Extracts point from the input point cloud which match PDAL expression and/or are inside of a cropping rectangle.

../../../../_images/point_cloud_filter.png

Rys. 24.18 Filtering of high vegetation class from an input point cloud layer

Parametry

Etykieta

Nazwa

Typ

Opis

Warstwa wejściowa

INPUT

[point cloud]

Input point cloud layer to export

Filter expression

Opcjonalne

FILTER_EXPRESSION

[wyrażenie]

A PDAL expression for selecting a subset of features in the point cloud data

Cropping extent

Opcjonalne

FILTER_EXTENT

[zasięg]

A map extent for selecting a subset of features in the point cloud data

Available methods are:

  • Calculate from layer…: uses extent of a layer loaded in the current project

  • Calculate from layout map…: uses extent of a layout map item in the active project

  • Calculate from bookmark…: uses extent of a saved bookmark

  • Use map canvas extent

  • Draw on canvas: click and drag a rectangle delimiting the area to take into account

  • Enter the coordinates as xmin, xmax, ymin, ymax

Przefiltrowane

OUTPUT

[point cloud]

Domyślnie: [Zapisz do pliku tymczasowego]

Specify the point cloud file to export the data to. One of:

  • Zapisz do pliku tymczasowego

  • Zapisz do pliku…

Wyniki

Etykieta

Nazwa

Typ

Opis

Przefiltrowane

OUTPUT

[point cloud]

Output point cloud layer with the filtered features of the input point cloud layer. Currently supported formats are .LAS, .LAZ, .COPC.LAZ and .VPC.

Kod pythona

ID algorytmu: pdal:filter

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.