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28.1.14. Point Cloud Extraction

NEW in 3.32

备注

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

28.1.14.1. Boundary

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

图 28.16 Extracting high vegetation and building polygons from an input point cloud layer

参数

Basic parameters

标注

名称

类型

描述

输入图层

INPUT

[point cloud]

Input point cloud layer to calculate boundary for

Resolution of cells used to calculate boundary

可选

RESOLUTION

[数字]

Resolution of cells used to calculate boundary

Minimal number of points in a cell to consider cell occupied

可选

THRESHOLD

[数字]

Minimal number of points in a cell to consider cell occupied

Boundary

OUTPUT

[vector: polygon]

默认: [保存到临时文件]

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

  • 保存到临时文件

  • 保存到文件…

Advanced parameters

标注

名称

类型

描述

Filter expression

可选

FILTER_EXPRESSION

[expression]

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

Cropping extent

可选

FILTER_EXTENT

[范围]

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

输出

标注

名称

类型

描述

Boundary

OUTPUT

[vector: polygon]

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

Python代码

Algorithm ID: pdal:boundary

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

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

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

参数

Basic parameters

标注

名称

类型

描述

输入图层

INPUT

[point cloud]

Input point cloud layer to export

Resolution of the density raster

RESOLUTION

[数字]

默认值：1.0

Cell size of the output raster

Tile size for parallel runs

TILE_SIZE

[数字]

Default: 1000

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

Density

OUTPUT

[栅格]

默认: [保存到临时文件]

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

  • 保存到临时文件

  • 保存到文件…

Advanced parameters

标注

名称

类型

描述

Filter expression

可选

FILTER_EXPRESSION

[expression]

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

Cropping extent

可选

FILTER_EXTENT

[范围]

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

可选

ORIGIN_X

[数字]

Y origin of a tile for parallel runs

可选

ORIGIN_Y

[数字]

输出

标注

名称

类型

描述

Density

OUTPUT

[栅格]

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

Python代码

Algorithm ID: pdal:density

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

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

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

参数

标注

名称

类型

描述

输入图层

INPUT

[point cloud]

Input point cloud layer to export

Filter expression

可选

FILTER_EXPRESSION

[expression]

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

Cropping extent

可选

FILTER_EXTENT

[范围]

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

[point cloud]

默认: [保存到临时文件]

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

  • 保存到临时文件

  • 保存到文件…

输出

标注

名称

类型

描述

Filtered

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.

Python代码

Algorithm ID: pdal:filter

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。