LAS (file format)

LAS (file format)
Name	LAS
Extension	.las, .laz
Type	Point cloud data format
Owner	ASPRS
Released	2003
Latest release	1.4

LAS (file format) is a public binary format for storage of three-dimensional point cloud data, primarily produced by airborne and terrestrial lidar sensors. It standardizes point attributes such as position, intensity, return number, and classification to enable interoperability between manufacturers, research groups, and government agencies. The format is maintained by the American Society for Photogrammetry and Remote Sensing and is widely used in mapping, surveying, forestry, civil engineering, and cultural heritage projects.

Overview

LAS is designed as an open, vendor-neutral container for lidar point observations acquired by systems from vendors such as Optech, Leica Geosystems, Riegl, and Teledyne and used by organizations like USGS, NASA, NOAA, and the European Space Agency. It provides a header describing coordinate offsets, scaling, creation software, and system identifiers plus a sequence of fixed-size point records. The format supports classification schemes aligned with standards used by agencies including FEMA, Ordnance Survey, and Natural Resources Canada, enabling integration with datasets from programs like National Elevation Dataset, Copernicus Programme, and DigitalGlobe acquisitions.

File format specification

The LAS specification defines file structure elements such as a public header block, variable length records, and point data records, with versions evolving to add fields for GPS time, color, and waveform packets. The header records metadata including file signature, GUIDs, system identifier, generating software, creation day/year, and offsets required for coordinate reconstruction, compatible with coordinate reference systems from agencies like EPSG and authorities like OGC. Point record formats (0–10 across versions) enumerate attributes—X, Y, Z integer coordinates with scale factors, intensity, return number, classification, scan angle, user data, and point source ID—so that processing tools from Esri, Fugro, Bentley Systems, and Trimble can read consistent binary layouts.

Coordinate systems and point data records

Coordinates in LAS are stored as scaled integers with scale and offset parameters in the header, allowing encoding of local projects tied to spatial references such as WGS 84, NAD83, and national grids like Ordnance Survey National Grid or EPSG:3857 when combined with auxiliary metadata. Point data records include multiple return information used in canopy penetration studies applied by organizations like US Forest Service and FAO, and classification codes used for ground/vegetation/building separation in workflows deployed by consultancies including AECOM and research groups at ETH Zurich and CSIC. Advanced point types incorporate RGB color for photogrammetric fusion used by teams at Airbus and Pix4D and waveform or time series attributes leveraged in projects at JPL and NOAA NMFS.

Compression and variants (LAZ)

LAZ is a lossless compressed variant of the format produced by the open-source LASzip compressor originating from the ISPRS community and maintained in tools by groups including Martin Isenburg and projects associated with LAStools. LAZ reduces storage and transfer costs for large lidar collections such as national inventories by factors often between 10× and 5× depending on point complexity, enabling distribution in repositories hosted by OpenTopography, USGS Earth Explorer, and regional portals like NLCD and INSPIRE. Compression retains all point attributes and supports streaming and indexing extensions used by cloud platforms from Amazon Web Services, Google Cloud, and Microsoft Azure for scalable processing.

Software and tool support

A broad ecosystem supports the format, including GIS suites like Esri ArcGIS, QGIS, point-cloud libraries such as PDAL, legacy suites like LAStools, and processing engines from Terrasolid and LASTools GUI variants. Visualization and editing tools include CloudCompare, Potree, and enterprise systems from Bentley, enabling integration with building information modeling workflows used by Autodesk and mapping platforms from Hexagon AB. Scientific programming languages and libraries—Python (programming language) bindings, R (programming language) packages, and C/C++ SDKs—provide read/write access for researchers at institutions like MIT and Stanford University.

Applications and use cases

LAS underpins applications in flood modeling and hydraulic mapping used by USACE and FEMA, forestry inventory and biomass estimation in projects by CIFOR and European Environment Agency, urban planning and cadastre mapping conducted by municipal authorities such as City of New York and London Boroughs, and archaeology and cultural heritage surveys executed by teams at British Museum and Smithsonian Institution. It is central to transportation corridor design by firms like AECOM and Jacobs Engineering, coastal change analysis by NOAA offices, and renewable energy siting analyses for companies involved with Ørsted and Vestas.

History and development

The format was introduced in the early 2000s under ASPRS stewardship to remedy proprietary fragmentation in lidar data exchange; major milestones include version 1.0 publication, subsequent additions of GPS time and waveform support, and the 1.4 release adding extended point formats for RGB and full waveform packet descriptors. Community contributors from academic centers such as University of Minnesota, industry partners like Leica Geosystems, and standards bodies including ISPRS and OGC have shaped extensions and best practices. Adoption accelerated with national lidar programs in the United States, United Kingdom, Canada, and EU member states under initiatives like INSPIRE, driving ecosystem tooling and compressed variants that support modern geospatial data infrastructures.

Category:Geospatial file formats