Svarbu

Vertimas yra bendruomenės pastangos, prie kurių jūs galite prisijungti. Šis puslapis šiuo metu išverstas 46.28%.

28.1.14. Taškų debesies ištraukimas

NEW in 3.32

Pastaba

Šie algoritmai galimi tik jei QGIS naudoja PDAL bibliotekos 2.5.0 ar naujesnę versiją.

28.1.14.1. Ribos

Eksportuoja poligono failą su taškų debesies sluoksnio ribomis. Jame gali būti skylės ir tai gali būti kelių dalių poligonas.

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

Fig. 28.16 Aukštos augmenijos ir pastatų poligonų ištraukimas iš įvesties taškų debesies sluoksnio

Parametrai

Baziniai parametrai

Užrašas

Pavadinimas

Tipas

Aprašymas

Įvesties sluoksnis

INPUT

[taškų debesis]

Įvesties taškų debesies sluoksnis ribų skaičiavimui

Resolution of cells used to calculate boundary

Optional

RESOLUTION

[number]

Resolution of cells used to calculate boundary

Minimal number of points in a cell to consider cell occupied

Optional

THRESHOLD

[number]

Minimal number of points in a cell to consider cell occupied

Boundary

OUTPUT

[vector: polygon]

Numatytas: [Įrašyti į laikiną failą]

Nurodykite taškų debesies failą, kurį naudoti kaip išvestį. Vienas iš:

  • Įrašyti į laikiną failą

  • Įrašyti į failą…

Advanced parameters

Užrašas

Pavadinimas

Tipas

Aprašymas

Filter expression

Optional

FILTER_EXPRESSION

[expression]

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

Cropping extent

Optional

FILTER_EXTENT

[extent]

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

Išvestys

Užrašas

Pavadinimas

Tipas

Aprašymas

Boundary

OUTPUT

[vector: polygon]

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

Python code

Algorithm ID: 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.

28.1.14.2. Density

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

Fig. 28.17 Point density (number of points per 2x2 m) as a raster

Parametrai

Baziniai parametrai

Užrašas

Pavadinimas

Tipas

Aprašymas

Įvesties sluoksnis

INPUT

[taškų debesis]

Input point cloud layer to export

Resolution of the density raster

RESOLUTION

[number]

Default: 1.0

Cell size of the output raster

Tile size for parallel runs

TILE_SIZE

[number]

Default: 1000

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

Density

OUTPUT

[raster]

Numatytas: [Įrašyti į laikiną failą]

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

  • Įrašyti į laikiną failą

  • Įrašyti į failą…

Advanced parameters

Užrašas

Pavadinimas

Tipas

Aprašymas

Filter expression

Optional

FILTER_EXPRESSION

[expression]

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

Cropping extent

Optional

FILTER_EXTENT

[extent]

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

Optional

ORIGIN_X

[number]

Y origin of a tile for parallel runs

Optional

ORIGIN_Y

[number]

Išvestys

Užrašas

Pavadinimas

Tipas

Aprašymas

Density

OUTPUT

[raster]

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

Python code

Algorithm ID: 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.

28.1.14.3. Filter

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

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

Fig. 28.18 Filtering of high vegetation class from an input point cloud layer

Parametrai

Užrašas

Pavadinimas

Tipas

Aprašymas

Įvesties sluoksnis

INPUT

[taškų debesis]

Input point cloud layer to export

Filter expression

Optional

FILTER_EXPRESSION

[expression]

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

Cropping extent

Optional

FILTER_EXTENT

[extent]

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

Filtered

OUTPUT

[taškų debesis]

Numatytas: [Įrašyti į laikiną failą]

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

  • Įrašyti į laikiną failą

  • Įrašyti į failą…

Išvestys

Užrašas

Pavadinimas

Tipas

Aprašymas

Filtered

OUTPUT

[taškų debesis]

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

Python code

Algorithm ID: 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.