skills/point-cloud-lidar/references/authoritative-sources.md

# Authoritative sources

- Last verified: 2026-07-19
- Review cadence: every 6 months
- Refresh triggers: LAS specification, USGS LiDAR specification, or PDAL major release

## Canonical sources

- [PDAL documentation](https://pdal.io/en/stable/) — point-cloud readers, filters, pipelines, and writers.
- [ASPRS LAS specification](https://lasformat.org/) — current published LAS format definition maintained by the ASPRS LAS Working Group.
- [USGS LiDAR Base Specification](https://www.usgs.gov/ngp-standards-and-specifications/lidar-base-specification-online) — quality, classification, and deliverable requirements.

Record acquisition type, LAS version and point format, CRS and vertical datum, units, density, class conventions, PDAL version, and every filter parameter.