LASzip - free and lossless LiDAR compression

LASzip - a free open source product of rapidlasso GmbH - quickly turns bulky LAS files into compact LAZ files without information loss. Terabytes of LAZ data are now available for free download from various agencies making LASzip, winner of the 2012 Geospatial World Forum Technology Innovation Award in LiDAR Processing and runner-up for innovative product at INTERGEO 2012, the de-facto standard for LiDAR compression.


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The LGPL-licensed LASzip library is easiest integrated via the DLL that is in the LASzip subdirectory of the LAStools distribtion. Other options are to link LASzip via the BSD-licensed libLAS library or to work with the LASlib library which fully integrates and enhances the LASzip codebase with spatial indexing, filters, transforms, geo-referencing, … of LAS and LAZ files.


  • See OSGeo4W for Windows .lib and include files to compile LASzip into your own application. libLAS binaries through OSGeo4W also link LASzip.
  • For explicit compression (decompression) of LAS (LAZ) files a Windows binary laszip.exe is available (command-line only laszip-cli.exe), as well as source code, examples, and makefiles to build your own LASzip on Windows, Linux, or MacOS.


  • The LASzip paper and video from the ELMF 2011 presentation in Salzburg, Austria. An interview with editor Christine Grahl of POB magazine.

LASzip is a compression library that was developed by Martin Isenburg for compressing ASPRS LAS format data in his LAStools. It has been provided as an LGPL-licensed stand-alone software library to allow other softwares that handle LAS data to read and write LASzip-compressed data. The BSD-licensed libLAS and the LGPL-licensed LASlib can take advantage of LASzip to read and write compressed data.

LASzip is completely lossless. It compresses bulky LAS files into compact LAZ files that are only 7-20 percent of the original size, accurately preserving every single bit. For example, compressing and decompressing the LAS file lidar.las with laszip.exe (command-line only laszip-cli.exe) as shown below results in lidar_copy.las that is bit-identical to lidar.las. However, the small size of lidar.laz makes it much easier to store, copy, transmit, or archive large amounts of LIDAR.

  • laszip -i lidar.las -o lidar.laz
  • laszip -i lidar.laz -o lidar_copy.las

LASzip compression can be many times smaller and many times faster than generic compressors like bz2, gzip, and rar because it knows what the different bytes in a LAS file represent. Another advantage of LASzip is that it allows you to treat compressed LAZ files just like standard LAS files. You can load them directly from compressed form into your application without needing to decompress them onto disk first. The availability of the LASzip DLL and two APIs, libLAS and LASlib, with LASzip capability makes it easy to add native LAZ support to your own software package.