[TCMUG] open source image compression expert

[Howard Butler]

On Aug 24, 2010, at 11:10 AM, Brian Fischer wrote:

> Brian,
> These tools work pretty good.  http://www.cs.unc.edu/~isenburg/lastools/  I would say Martin Isenburg is leading this area.  We're considering using his tools in the Red River Basin app.

Martin's tools are technically not open source.  The source code is available, but they do not have a license.  They should be considered All Rights Reserved, and he could relicense them to whomever he wishes and leave you out in the cold.

> 
> Right now we have had good luck compressing the LiDAR with 7-zip.  That is what this app does on the zip and ship process.  http://gis.rrbdin.org/lidardownload/index.html 

Martin's laszip code has an LGPL license on it <http://hg.liblas.org/zip>, but it is not yet ready for prime time.  I have been working to integrate it into libLAS, but that work is not done yet.  High-volume lidar shops have also had good compression success with rar, which does an analysis pass of .las files that works well enough with .las file's rather cyclical nature.  Run-length compressors do not do so well with .las because there isn't usually long runs of data to squeeze out.  Martin's laszip code is compresses faster and tighter than rar, but as I said rather rough to use.