What is the LAS Format?
The LAS file format is a public file format for the interchange of 3-dimensional point cloud data data between data users. Although developed primarily for exchange of lidar point cloud data, this format supports the exchange of any 3-dimensional x,y,z tuplet. This binary file format is an alternative to proprietary systems or a generic ASCII file interchange system used by many companies. The problem with proprietary systems is obvious in that data cannot be easily taken from one system to another. There are two major problems with the ASCII file interchange. The first problem is performance because the reading and interpretation of ASCII elevation data can be very slow and the file size can be extremely large even for small amounts of data. The second problem is that all information specific to the lidar data is lost. The LAS file format is a binary file format that maintains information specific to the lidar nature of the data while not being overly complex.
The LAS 1.4 Specification was approved by the ASPRS Board on November 14, 2011, and is the most recent approved version of the document. Download the latest revision at the following link:
ASPRS LAS 1.4 Format Specification R15 July 9 2019
[Update: July 26, 2013] The lidar mapping community now has the ability to customize the LAS file format to meet their application-specific needs. The mechanism that makes this possible is the LAS Domain Profile which is a derivative of the base LAS v1.4 specification that adds (but does not remove or alter existing) point classes and attributes. For example the Topo-Bathy Lidar Domain Profile adds point classification values for bathymetric point (e.g. seafloor or riverbed; also known as submerged topography) water surface derived water surface submerged object IHO S-57 object and bottom-not-found depth. Extra Byte Variable Length Records (EXTRA_BYTES or Extra Byte VLRs) are added for pseudo-reflectance uncertainty water column depth figure of merit and processing specific flags. We anticipate the release of additional domain profiles in the future; proposed additional domain profiles should be provided utilizing the LAS Domain Profile Description Template.
[Update: March 27, 2019] Maintenance of the ASPRS LAS Specification moved onto GitHub, a collaborative development platform. This transition was motivated by the need for (1) greater transparency into the LAS Working Group decision-making process, (2) a historical archive of design rationale, (3) increasing industry collaboration and communication, (4) a reliable communication platform for updates, and (5) a straightforward revision history between versions. This platform was used to develop Revision 14 of the LAS 1.4 specification and represents a significant usability and aesthetic upgrade.
Work on LAS 2.0 has been suspended indefinitely.
To download copies of superseded ASPRS LAS specifications go to:
Superseded ASPRS LAS 1.4 Format Specification R14 March 26 2019 (PDF)
Superseded ASPRS LAS 1.4 Format Specification R13 July 15 2013 (PDF)
Superseded ASPRS LAS 1.3 Format Specification October 24 2010 (PDF)
Superseded ASPRS LAS 1.2 Format Specification September 2 2008 (PDF)
Superseded ASPRS LAS 1.1 Format Standard May 7 2005 (PDF)
Superseded ASPRS LAS 1.0 Format Standard May 9 2003 (PDF)
Follow this link to register for a unique LAS key: https://www.asprs.org/Misc/LAS-Key-Request-Form.html