LAS/LAZ with 24 bytes of extra bytes fails to load with LAS reader error Extra byte specification exceeds point length beyond base format length #62496
Description
What is the bug or the crash?
Certain LAZ files with many extra bytes will not load in QGIS, which returns the error readers.las: Extra byte specification exceeds point length beyond base format length.
This particular file has 8 extra bytes fields, for 24 additional bytes on top of the base 30 bytes for LAS 1.4 format 6, for 54 bytes per point in total. It has 5 floating point fields, two unsigned chars and one unsigned short.
The error is triggered whether using LAS or LAZ format.
Other viewers, including LP360 and one in-house do not reject this file. lasvalidate and other LAStools raise no errors. pdal info --all (PDAL 2.9) processes the file without error.
This sample file is a tiny clip from a much larger file, and identifying information has been removed. It still triggers the error.
Invalid Data Source : F:/Data/Repros/QGIS Extra Bytes/sample.laz is not a valid or recognized data source, error: "readers.las: Extra byte specification exceeds point length beyond base format length."
Steps to reproduce the issue
- Drag the sample file into QGIS, OR
Layer > Add Layer > Add Point Cloud Layer...and select the file - Observe the error bar and message in the messages window.
Versions
Observed with two QGIS versions:
3.40.8 from Latest QGIS LTS downloadable installer
| QGIS version | 3.40.8-Bratislava |
| QGIS code revision | efaf8952e0 |
| Libraries | |
| Qt version | 5.15.13 |
| Python version | 3.12.11 |
| GDAL version | 3.11.0 — Eganville |
| PROJ version | 9.6.2 |
| EPSG Registry database version | v12.013 (2025-05-26) |
| GEOS version | 3.13.1-CAPI-1.19.2 |
| SQLite version | 3.46.1 |
| PDAL version | 2.9.0 |
| PostgreSQL client version | unknown |
| SpatiaLite version | 5.1.0 |
| QWT version | 6.3.0 |
| QScintilla2 version | 2.14.1 |
| OS version | Windows 11 Version 2009 |
| Active Python plugins | |
| db_manager | 0.1.20 |
| grassprovider | 2.12.99 |
| MetaSearch | 0.3.6 |
| processing | 2.12.99 |
3.44.0 from latest OSGeo4W
| QGIS version | 3.44.0-Solothurn |
| QGIS code revision | 5d9ba037df1 |
| Libraries | |
| Qt version | 5.15.13 |
| Python version | 3.12.11 |
| GDAL version | 3.11.0 (Compiled) 3.11.1 (Running) — Eganville |
| PROJ version | 9.6.2 |
| EPSG Registry database version | v12.013 (2025-05-26) |
| GEOS version | 3.13.1-CAPI-1.19.2 |
| SQLite version | 3.46.1 |
| PDAL version | 2.9.0 |
| PostgreSQL client version | 17.3 |
| SpatiaLite version | 5.1.0 |
| QWT version | 6.3.0 |
| QScintilla2 version | 2.14.1 |
| OS version | Windows 11 Version 2009 |
| Active Python plugins | |
| GroupStats | 2.2.7 |
| <SNIP!> | <SNIP!> |
| quick_map_services | 0.21.2 |
| RasterAttributeTable | 1.2 |
| rasterstats | 0.4.3 |
| SRTM-Downloader | 3.2.3 |
| db_manager | 0.1.20 |
| MetaSearch | 0.3.6 |
| processing | 2.12.99 |
Supported QGIS version
- I'm running a supported QGIS version according to the roadmap.
New profile
- I tried with a new QGIS profile
Additional context
No response