Compressing and decompressing LiDAR data with LASTools

LiDAR files are quite large. LASTools provides an efficient way to compress and decompress them.

LiDAR files with the .las extension are not compressed. Those with .laz are compressed.

Compressing

• Open the Windows command prompt:Win + X then select Command prompt
• Navigate to the project folder: CD C:\GossanHill
• My project folder contains these items:

29/03/2017  04:32 PM           946,176 las2las.exe
28/03/2017  09:25 AM           913,408 las2txt.exe
29/03/2017  04:19 PM           999,424 lasinfo.exe
28/03/2017  09:26 AM           966,656 laszip.exe
30/03/2017  08:17 PM     1,186,327,293 Merged.las

• Enter a command like this: laszip Merged.las
• laszip is the program to run
• Merged.las is the file to act upon

The program runs for a little while, then you’ll see that a new file Merged.laz has been created. It is roughly 15% the size of the uncompressed file. If there’s already a Merged.laz file, then it will be over-written.

Decompressing

The reverse process is virtually the same. Use the same command, but provide a .laz file as an input. Here’s an example: laszip Merged.laz. If there’s already a Merged.las file, then it will be over-written.

This article is part of the Orienteering Mapping with LiDAR, Smartphones and Free Tools series.

Polite and constructive responses are always welcome.