readers.las

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readers.las#

The LAS Reader supports reading from LAS format files, the standard interchange format for LIDAR data. The reader does NOT support point formats containing waveform data (4, 5, 9 and 10).

The reader also supports compressed LAS files, known as LAZ files or LASzip files. In order to use compressed LAS (LAZ), your version of PDAL must be built with one of the two supported decompressors, LASzip or LAZperf. See the compression option below for more information.

Note

LAS stores X, Y and Z dimensions as scaled integers. Users converting an input LAS file to an output LAS file will frequently want to use the same scale factors and offsets in the output file as existed in the input file in order to maintain the precision of the data. Use the forward option on the writers.las to facilitate transfer of header information from source to destination LAS/LAZ files.

Note

LAS 1.4 files can contain datatypes that are actually arrays rather than individual dimensions. Since PDAL doesn’t support these datatypes, it must map them into datatypes it supports. This is done by appending the array index to the name of the datatype. For example, datatypes 11 - 20 are two dimensional array types and if a field had the name Foo for datatype 11, PDAL would create the dimensions Foo0 and Foo1 to hold the values associated with LAS field Foo. Similarly, datatypes 21 - 30 are three dimensional arrays and a field of type 21 with the name Bar would cause PDAL to create dimensions Bar0, Bar1 and Bar2. See the information on the extra bytes VLR in the LAS Specification for more information on the extra bytes VLR and array datatypes.

Warning

LAS 1.4 files that use the extra bytes VLR and datatype 0 will be accepted, but the data associated with a dimension of datatype 0 will be ignored (no PDAL dimension will be created).

Default Embedded Stage

This stage is enabled by default

Streamable Stage

This stage supports streaming operations

Example#

[
    {
        "type":"readers.las",
        "filename":"inputfile.las"
    },
    {
        "type":"writers.text",
        "filename":"outputfile.txt"
    }
]

Options#

_`filename`

LAS file to read [Required]

count

Maximum number of points to read. [Default: unlimited]

override_srs

Spatial reference to apply to the data. Overrides any SRS in the input itself. Can be specified as a WKT, PROJ or EPSG string. Can’t use with ‘default_srs’. [Default: none]

default_srs

Spatial reference to apply to the data if the input does not specify one. Can be specified as a WKT, PROJ or EPSG string. Can’t use with ‘override_srs’. [Default: none]

_`start`

Point at which reading should start (0-indexed). Useful in combination with ‘count’ option to read a subset of points. [Default: 0]

_`extra_dims`

Extra dimensions to be read as part of each point beyond those specified by the LAS point format. The format of the option is <dimension_name>=<type>[, ...]. Any valid PDAL type can be specified.

Note

The presence of an extra bytes VLR when reading a version 1.4 file or a version 1.0 - 1.3 file with use_eb_vlr set causes this option to be ignored.

_`use_eb_vlr`

If an extra bytes VLR is found in a version 1.0 - 1.3 file, use it as if it were in a 1.4 file. This option has no effect when reading a version 1.4 file. [Default: false]

compression

May be set to “lazperf” or “laszip” to choose either the LazPerf decompressor or the LASzip decompressor for LAZ files. PDAL must have been built with support for the decompressor being requested. The LazPerf decompressor doesn’t support version 1 LAZ files or version 1.4 of LAS. [Default: ‘none’]

ignore_vlr

A comma-separated list of “userid/record_id” pairs specifying VLR records that should not be loaded.

fix_dims

Make invalid dimension names valid by converting disallowed characters to ‘_’. Only applies to names specified in an extra-bytes VLR. [Default: true]

nosrs

Don’t read the SRS VLRs. The data will not be assigned an SRS. This option is for use only in special cases where processing the SRS could cause performance issues. [Default: false]

threads

Thread pool size. Number of threads used to decode laz chunk tables (Default: 7)

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