blockedPointCloud

Point cloud made from discrete blocks

Since R2022a

Description

A blockedPointCloud object is a point cloud made from discrete blocks. Use blocked point clouds when a point cloud is too large to fit into memory. With a blocked point cloud, you can perform processing without running out of memory.

Creation

Syntax

bpc = blockedPointCloud(source,blockSize)

bpcs = blockedPointCloud(sources,blockSize)

bpc = blockedPointCloud(___,Name=Value)

Description

bpc = blockedPointCloud(source,blockSize) creates a read-only blockedPointCloud object from the specified source source with the specified block size blockSize. The source can be a pointCloud object or the name of a file or folder that contains point cloud data.

bpcs = blockedPointCloud(sources,blockSize) creates an array of blockedPointCloud objects from multiple sources sources with the specified block size blockSize. The length of bpcs is equal to the number of sources in sources.

bpc = blockedPointCloud(___,Name=Value) specifies the Adapter and AlternateFileSystemRoots properties using one or more name-value arguments.

Input Arguments

source — Source of point cloud data

pointCloud object | character vector | string scalar

Source of the point cloud data, specified as a pointCloud object, or as a character vector or string scalar specifying the name of a file or folder.

The blockedPointCloud function supports these source formats:

• Single LAS or LAZ file.

• pointCloud object.

• Name of file or folder that contains point cloud data.

sources — Sources of point cloud data

cell array of character vectors | string array | Fileset object

Sources of the point cloud data, specified as a cell array of character vectors, string array, or FileSet object. blockedPointCloud function creates an array of blockedPointCloud objects.

blockSize — Size of blocks

scalar | two-element row vector | three-element row vector

Size of the blocks, specified as a scalar, a two-element row vector, or a three-element row vector. The value you specify determines which dimensions the function blocks the point cloud along.

• Scalar — The function blocks the point cloud along the X-axis.

• Two-element row vector — The function blocks the point cloud along the X- and Y-axes.

• Three-element row vector — The function blocks the point cloud along the X-, Y- and Z-axes.

Properties

Adapter — Read and write interface for blocked point cloud object

LAS object | InMemory object | LASBlocks object | MATBlocks object

Read and write interface for the blocked point cloud object, specified as one of these adapter objects.

Source of Point Cloud Data	Adapter	Description
Single LAS/LAZ file FileSet object containing LAS/LAZ files	LAS	Store blocks in a single LAS file
A pointCloud object.	InMemory	Store blocks in a variable in main memory
Name of the folder which is the output of the apply or write function, stored using LASBlocks adaptor.	LASBlocks	Stores each block as a LAS file in a folder
Name of the folder which is the output of the apply or write function, stored using MATBlocks adaptor.	MATBlocks	Stores each block as a MAT file in a folder

You can also create your own adapter using the lidar.blocked.Adapter class.

To set this property, you must specify it at object creation.

Example: Adapter=lidar.blocked.LAS

AlternateFileSystemRoots — Alternate file system path

string array | character vector | cell array of character vectors

Alternate file system path for the files specified in the source, specified as a string array, character vector, or cell array of character vectors containing one or more rows. Each row specifies a set of equivalent root paths.

Example: AlternateFileSystemRoots=["Z:\datasets", "/mynetwork/datasets"]

Data Types: char | string | cell

BlockSize — Size of blocks

scalar | two-element row vector | three-element row vector

Size of the blocks, specified as a scalar, a two-element row vector, or a three-element row vector. The value you specify determines which dimensions the function blocks the point cloud along.

• Scalar — The function blocks the point cloud along the X-axis.

• Two-element row vector — The function blocks the point cloud along the X- and Y-axes.

• Three-element row vector — The function blocks the point cloud along the X-, Y- and Z-axes.

Data Types: double

ClassUnderlying — Class of underlying source

string

This property is read-only.

Class of underlying source, stored as a string scalar.

Data Types: string

SizeInBlocks — Size expressed as number of blocks

three-element row vector of positive integers

This property is read-only.

Size expressed as the number of blocks, specified as a three-element row vector of positive integers. The element of the vector specify the number of blocks in the X-, Y- and Z-axes respectively. This property is dependent on the BlockSize property. The value includes partial blocks.

Data Types: integer

Source — Source of point cloud data

pointCloud object | character vector | string scalar

This property is read-only.

Source of the point cloud data, specified as a pointCloud object, or as a character vector or string scalar specifying the name of a file or folder.

Data Types: char | string

XLimits — Range of coordinates along X-axis

two-element row vector

This property is read-only.

Range of coordinates along the X-axis, specified as a two-element row vector. The first and second elements represent the minimum and maximum values of point cloud coordinates along the X-axis, respectively.

Data Types: double

YLimits — Range of coordinates along Y-axis

two-element row vector

This property is read-only.

Range of coordinates along the Y-axis, specified as a two-element row vector. The first and second elements represent the minimum and maximum values of point cloud coordinates along the Y-axis, respectively.

Data Types: double

ZLimits — Range of coordinates along Z-axis

two-element row vector

This property is read-only.

Range of coordinates along the Z-axis, specified as a two-element row vector. The first and second elements represent the minimum and maximum values of point cloud coordinates along the Z-axis, respectively.

Data Types: double

Object Functions

apply	Process blocks of blocked point cloud
blocksub2roi	Convert block subscripts to ROI limits
gather	Collect blocks of blocked point cloud into workspace
getBlock	Read specific block of blocked point cloud
getRegion	Read arbitrary region of blocked point cloud
roi2blocksub	Convert ROI to block subscripts
write	Write blocked point cloud data to new destination

Examples

Create Blocked Point Cloud

Create a blocked point cloud from a LAZ file.

pcfile = fullfile(toolboxdir("lidar"),"lidardata", ...
                        "las","aerialLidarData.laz");
 
bpc = blockedPointCloud(pcfile,[50 50]);

Display the details of the blocked point cloud.

disp(bpc)

  blockedPointCloud with properties:

   Read-only properties.
             Source: "/mathworks/devel/bat/filer/batfs1904-0/Bdoc24a.2528353/build/matlab/toolbox/lidar/lidardata/las/aerialLidarData.laz"
            Adapter: [1x1 lidar.blocked.LAS]
       SizeInBlocks: [9 6 1]
            XLimits: [4.2975e+05 4.3015e+05]
            YLimits: [3.6798e+06 3.6801e+06]
            ZLimits: [72.7900 125.8200]
    ClassUnderlying: "pointCloud"

   Settable properties
          BlockSize: [50 50 53.0300]

Version History

Introduced in R2022a