LASzip - lossless LAS compression

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LASzip - lossless LAS compression

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Please note that libLAS links to the LASzip compression library while LASlib embeds the LASzip codebase.

Binaries

  • 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, as well as the source code and a makefile to build laszip on Windows, Linux, or MacOS.

Documentation

  • The LASzip paper and video from the ELMF 2011 presentation in Salzburg, Austria.

Development Source

Background

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 10-20 percent of the original size, accurately preserving every single bit. For example, compressing and decompressing the LAS file lidar.las with laszip.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 lidar.las lidar.laz
  • laszip lidar.laz 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 two APIs, libLAS and LASlib, with LASzip capability makes it very easy to add native LAZ support to your own software package.

Download LAZ data

© Copyright 2011, Martin Isenburg. Created using Sphinx 1.1.2.