While on the subject of handling large LiDAR datasets, I would be interested in hearing from people who are using the LiDAR Compressor from LizardTech. I have not heard or seen very much about this product since its introduction last year. The claim is 25% of the file size with 100% of the data – lossless.
If you have any experience working with this product please let us all know.
Have tried it, but not in production. Reduction of filesize is 25-35% – however the problem is that most software does not support this new format yet, so only LizardTechs software can work with the data. GlobalMappper (www.globalmapper.com) have decent support for the new format (if you download the latest patch from the forums). Regarding accuracy I am also curious.
Thanks STH, I was wondering about software support. Given the drop in the cost of disk space for our work flow being able to access the data in a timely manner trumps any need for a reduction in file size.
Martin Isenburg’s LasTools (http://www.cs.unc.edu/~isenburg/lastools/) has a LAS compression utility (lazip) which has pretty good performance and ~10:1 lossless compression ratio. The guy’s smart and it’s free.
I haven’t seen any comparisions with it vs the LizardTech compressor but it’s probably a good start before jumping down the LizardTech pay per use rabbit hole.
Thanks for your nice words, Wolf. One year ago my LASzip compressor was only an experimental / academic prototype. In the meantime I completely rewrote it to be a well-designed, backwards compatible, and maintainable coder that can handle the LAS 1.X spec as it evolves. The LASzip compressor is free (with a LGPL license), has been integrated into two open source libraries (libLAS and LASlib), and will soon show up in major vendor products. More info on: http://laszip.org/
The free LASzip compressor is now in version 2.0.2 allowing random access decompression which is a major improvement over version 1.0. It already has native support in FME 2012, TopoDOT, LAStools, and more and more vendors will be adding it in their next releases.
The largest collection of LAZ content is provided by the DNR Minnesota. You will soon find LIDAR for the entire state online as compressed LAS. Here the growing list of counties that are completed:
- ftp://lidar.dnr.state.mn.us/data/raw/county/dodge/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/douglas/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/faribault/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/fillmore/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/freeborn/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/houston/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/jackson/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/lesueur/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/martin/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/mower/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/murray/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/nobles/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/olmsted/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/pine/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/pope/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/rice/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/rock/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/steele/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/wabasha/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/waseca/laz/
- ftp://lidar.dnr.state.mn.us/data/raw/county/winona/laz/