Five Myths about LAS, LAZ, and “Optimized LAS”

The Open Letter by OSGeo was delivered to ESRI, OGC, and the ASPRS last week and the initial reponses – including an email from ESRI’s founder and president Jack Dangermond – are very encouraging. Attendees of last weeks’ ASPRS conference were discussing how to respond to ESRI’s proprietary “Optimized LAS” that threatens the achievements of the open LiDAR formats LAS and LAZ that the community has been using for many years now. Below five clarifications to five wrong statements overheard at these meetings:

1) Martin’s “LAZ” format is also proprietary.

Wrong. LAZ – just like LAS – is an open format. LAZ is defined by a well commented open reference implementation in C/C++ and described in a PE&RS paper published in February 2013. LAS is defined via a specification document but has no reference implementation. Both can be freely used by anyone and (re-)implemented on any operating system and in any programming language. For example, there is now a javascript version of LAZ that someone else created.

2) We have no argument because ESRI provides a free API for “Optimized LAS”.

Wrong. “Optimized LAS” can only be used via the mechanism, the programming language, and the operating system of ESRI’s choosing. This is the very definition of “proprietary format”. Here is what Wikipedia says:

A proprietary format is a file format of a company, organization, or individual that contains data that is ordered and stored according to a particular encoding-scheme, designed by the company or organization to be secret, such that the decoding and interpretation of this stored data is only easily accomplished with particular software or hardware that the company itself has developed. The specification of the data encoding format is not released, or underlies non-disclosure agreements.

In contrast an open format is a file format that is published and free to be used by everybody.

3) Martin’s “LAZ” format is only used by LAStools.

Wrong. Large parts of the LiDAR industry embrace LAZ and have added read & write support for the LAZ format using the open source code or the DLL. Examples are QT Modeler, Globalmapper, FME, Fugroviewer, ERDAS IMAGINE, ENVI LiDAR, Bentley Pointools, TopoDOT, FUSION, CloudCompare, Gexel R3, Pointfuse, …and many more. Notable exceptions are ArcGIS and the product line offered by Lewis Graham’s GeoCue group. We maintain an (incomplete) list of software with native LAZ support here.

4) ESRI has engineered “Optimized LAS” for the cloud and “LAZ” cannot compete.

Wrong. The extra functionality in “Optimized LAS” is a simple mash-up of LAZ with spatial indexing LAX, an optional spatial sort, and a few extra statistics. This is why ESRI’s format is also known as the “LAZ clone”. We were able to feature-match these minor engineering changes in an afternoon which – a few days later – resulted in this April Fools’ Day prank. In fact, LAZ has been used “in the cloud” for well over 4 years on OpenTopography – the first and probably the premier Web accessible LiDAR cloud service of our industry. It is also used by many other LiDAR download servers. We maintain an (incomplete) list of portals offering compressed LAZ here.

5) ESRI’s “Optimized LAS” does not prevent people from using LAS.

ESRI is one of the largest GIS training organizations. If they teach hundreds of LiDAR novices to “optimize” their “unoptimized LAS” files while simultaneously lobbying large LiDAR providers into switching from LAS or LAZ to zLAS they will effectively destroy the current success of our open formats. ESRI’s command of the GIS market can – little by little – turn their own proprietry format into the dominant way in which LiDAR point clouds are exchanged. Then we loose our open exchange formats. Hence, ESRI’s proprietary “Optimized LAS” format “threatens” what we have achieved with LAS (and LAZ): open LiDAR data exchange and incredible LiDAR software interoperability.

This is not an anti-ESRI campaign. We hope to work with ESRI to resolve this situation. Below an image and a quote from ESRI’s ArcNews Spring 2011 news letter about the importance of open formats, standards, and specifications …

ESRI: "Esri continues to advocate the need for open access to geographic data and functionality through support for widely adopted and practical standards and specifications. Esri follows an open system strategy for accessing and using geographic data and functionality."

“Esri continues to advocate the need for open access to geographic data and functionality through support for widely adopted and practical standards and specifications. Esri follows an open system strategy for accessing and using geographic data and functionality.” — ArcNews, Spring 2011

New LASliberator “frees” LiDAR from Closed Format

PRESS RELEASE (for immediate release)
April 20, 2015
rapidlasso GmbH, Gilching, Germany

The latest product by rapidlasso GmbH – creators of LAStools and LASzip – is an open source tool aiming to liberate LiDAR points locked-up in proprietary “Optimized LAS” – a highly controversial, closed LiDAR format. The new LASliberator can be downloaded here. It comes as both, a simple command line tool for scripting and with an easy-to-use graphical interface.

The GUI version of the LASliberaor has a simple and easy-to-use interface.

The GUI of the “LASliberator” has a simple, easy-to-use interface.

The LASliberator reads LiDAR points from closed “Optimized LAS” files that use the “.zlas” extension and converts them to open ASPRS LAS files that use the “.las” extension. Alternatively, the points can be stored to compressed LAZ files – using the open source LASzip compressor – that use the “.laz” extension. In addition, the tool creates tiny spatial indexing files that use the “.lax” extension. These can then be exploited for accelerated area-of-interest queries via open source LASindex when using LAStools or the latest version of the LASzip DLL.

Note that the LASliberator cannot entirely be open source as it depends on a particular proprietry library. The closed nature of the “Optimized LAS” format does not allow for a full open source implementation. It is therefore not possible to port the LASliberator to other operating systems or into other programming languages.

Selecing open in the GUI pops up a file selection dialogue allowing the user to find the file that is to be set free.

The user can select a file to liberate by pressing “open” in the GUI.

The new LASliberator comes on the heels of an outcry in the community over the LiDAR format fragmentation “Optimized LAS” is creating. It provides an immediate solution to go from closed zLAS to open LAZ for people whose LiDAR got stuck in yet-another-proprietary-format.

About rapidlasso GmbH:
Technology powerhouse rapidlasso GmbH specializes in efficient LiDAR processing tools that are widely known for their high productivity. They combine robust algorithms with efficient I/O and clever memory management to achieve high throughput for data sets containing billions of points. The company’s flagship product – the LAStools software suite – has deep market penetration and is heavily used in industry, government agencies, research labs, and educational institutions. Visit for more information.

The LAS format, the ASPRS, and the “LAZ clone” by ESRI

We are concerned about ESRI’s next moves in forcing yet another proprietary format into wide-spread deployment. Forwarded emails, retold conversations, and personal experiences suggest that sneaky tactics are being used to disrupt the harmony in open LiDAR formats that we have enjoyed for many years.

laz_and_lazclone_smallSome time has passed since we broke the news about the proprietary “LAZ clone” by ESRI. We were expecting the ASPRS to eventually comment on the issue. ESRI is promoting their lock-in product by the name of the open LAS specification (for which the ASPRS holds the copyright) calling their closed format “Optimized LAS“. We have been asked (in various forums) about the position of the ASPRS on this issue. ESRI’s use of LAS (*) makes it seem as if their “LAZ clone” was somehow an ASPRS thing (as evidenced by Harold’s comment). Despite ESRI’s media-blah-blah about “open and interoperable” they are – once again – luring the geospatial community to fall for a new proprietary format. So far the ASPRS has not released a statement on ESRI’s closed version of the LAS format.

The LAS Working Group (LWG) is part of the Lidar Division of the ASPRS. It has been maintaining the evolving LAS format from its 1.0 version that was (apparently as early as 1998) created by the LiDAR industry’s pioneers and eventually donated to the ASPRS (more recent LAS history is linked here). The good and early decisions of the LWG have created an incredible successful open data exchange standard for discrete LiDAR points that is nowadays supported by practically every software. “Kudos” to the original members for this achievement.

We did not join the LWG until 2011 to help avoid broken compatibility in LAS 1.4. After weathering the following “laser storm of 2011” the working group has been rather quiet. Its most recent activity was in 2013 for tendering the development of an official ASPRS LAS Validation Suite (LVS) that eventually resulted in ‘lasvalidate‘  – an open source LAS validator.

So who is this LWG? And why are they not commenting on such an important controvery like this “LAZ clone” with the seductive name “Optimized LAS”? The latest document on the Web pages of the LAS Working Group (LWG) lists the following people as members:


This list from 2011 is hopelessly out of date, but it should give you an idea of the composition of the LWG. Most likely rapidlasso is still a member of the LWG but it is hard to tell because there have not been any emails recently and because there are no regular meetings. In the past we had some real bad luck with bringing up issues directly with the LWG, so here we go:

Dear ASPRS and LWG,
we are the guardians of the open LiDAR data exchange
specification, the LAS format. What is our response
to the proprietary format called "Optimized LAS" that
is being agressively promoted by ESRI?

Dear concerned ASPRS member,
how would you like your organization to respond now
that a large geospatial company uses its dominance
to push a closed format into the market, sabotaging
the accomplishments of an open data exchange standard
maintained by the ASPRS.

We are worried that ESRI – beyond lobbying agencies to convert their current holdings to the proprietary “LAZ clone” or to tender future deliveries in the closed zLAS format – may also be trying to form strategic alliances with vendors of popular LiDAR processing packages. Many of these vendors are also members of the LAS Working Group and would be in a conflict-of-interest if they were to “sell out” to ESRI’s lock-in ambitions.

You can imagine the red flag that went up a few days ago when we saw a technical comment on a LinkedIn post by Gene Roe that suggested intimate familiarity with the capabilities of the “LAZ clone” by Lewis Graham who has been leading the LAS effort since 1998 and who is the chair of the LAS Working Group. That Lewis’ comment has since been removed did little to calm our worries. As a side note: Gene’s posts being titled “LAS Data Format” further dilutes the difference between open LAS and closed zLAS.

Please inform us (or comment below) about any lobbying you hear about. Given the agressive moves by ESRI – in face of our repeated attempts to reach out – we do not think we can afford to err on the side of caution any longer … (-;


(*) It is fair to note that our products such as LAStools, LASlib, and LASzip also use the name “LAS”. This is for historic reasons. That is what we called the simple package for reading, writing, and processing LAS files we created back in 2005 for our own research before releasing them as open source in 2007. During our postdoc years at UC Berkeley we did not anticipate that these tools would become so or that we would start a company a few years later …

Rapidlasso Announces LASzip “Compatibility Mode” For LAS 1.4

PRESS RELEASE (for immediate release)
October 6, 2014
rapidlasso GmbH, Gilching, Germany

Just in time for INTERGEO 2014 in Berlin, rapidlasso GmbH has completed the first prototype that extends the LASzip LiDAR compressor to the new point types 6 to 10 introduced with the LAS 1.4 specification. Sponsored in part by NOAA, this upgrade introduces the new “Compatibility Mode” for LAS 1.4 that deploys a clever point re-coding strategy so that legacy LiDAR software – without LAS 1.4 support – can readily read the new point types as well.

The new “Compatibility Mode” is realized by re-coding the new point types 6 to 10 of the LAS 1.4 specification into corresponding older point types 1, 3, 4 or 5 of the LAS 1.3 specification and by storing all new attributes (e.g. more classifications, higher-resolution scan angles, wider return counters, …) as “extra bytes”. This results in a lossless and forward-compatible format that has several advantages:
(1) existing legacy software can readily read the re-encoded LAS 1.4 files,
(2) the popular LASzip compressor can trivially compress and decompress re-encoded LAS 1.4 content,
(3) easier adaptation of the new LAS 1.4 point types by mitigating their impact on existing LAS 1.3 workflows, and
(4) extra time gives geospatial players the opportunity to jointly develop the final native LAS 1.4 compressor and avoid fragmenting compressed LiDAR into incompatible formats.

About LASzip:
The LASzip compressor is the de-facto industry standard for compressed LiDAR and supported by numerous software packages (see or picture below). This open source compression scheme achieves lossless compression ratios from 1:5 to 1:12 and processes several million points per seconds making it winner of the Geospatial World Award for LiDAR Processing in 2012 and runner up for most innovative product at the Wichmann INTERGEO 2012 Awards.

An ever-growing list of software with native LAZ support as well as LiDAR download portals serving LAZ is available at

First ever LiDAR Processing Model in QGIS using LAStools

We at rapidlasso had finally the chance to meet Victor Olaya of Boundless who created the Processing framework (formerly know as Sextante) that is now integral part of QGIS. On the last day of the joint workshop organized by Dr. Lene Fischer at the Forest and Landscape department of the University of Copenhagen that saw 2 days of LiDAR processing with LAStools followed by 2 days of GIS exercises with QGIS and Processing, we decided to do an impromptu, unscripted, and unplanned experiment in front of the course participants, doing something none of us had tested before:

We wanted to see if we would be able to use the existing LAStools and QGIS Processing functionalities to create a LiDAR Processing Model that would take a single LAZ or LAS file as input, find the bare-earth points with lasground, compute the height of each point above the ground with lasheight, look in the remaining points for buildings and vegetation with lasclassify, generate a set of polygons around the building points with lasboundary, and open the resulting shapefile in QGIS.

After some discussion a Processing Model was decided upon. Holding our breath we started it. SUCCESS! On the first try! It was a nice way to conclude our 4 days of LAStools and QGIS training as you see below … (-:

See this blog entry (also see the blog’s comment section) for information on how to add LAStools to your QGIS Processing toolboxes.

Esri and rapidlasso develop joint LiDAR compressor

PRESS RELEASE (April Fools’ Day)
April 1, 2014
rapidlasso GmbH, Gilching, Germany

In a positive spin of events, Esri and rapidlasso are announcing to join forces and together develop a LiDAR compressor for LAS 1.4 in open source avoiding unnecessary format fragmentation. Their new “LASeasy” tool not only compresses but also optimizes LAS files for efficient area-of-interest queries. LASeasy extends the popular LASzip compressor to handle LAS 1.4 content and includes the tiny spatial indexing *.lax files into the *.laz file via Extended Variable Length Records (EVLRs). More importantly, LASeasy provides new features such as optional spatial sorting and precomputed statistics – motivated by Esri – that allow exploiting LiDAR in the cloud.

To minimize disruption in existing workflows, their joint effort uses a clever strategy that capitalizes on the natural “break” in the ASPRS LAS format from version 1.3 to 1.4. LAS files compressed by Esri will automatically be upgraded to the new point types introduced with LAS 1.4 (and be losslessly downgraded on decompression). LiDAR software already supporting LAZ will instantly be able to read all LiDAR produced by Esri with the same DLL update that will be needed to access future compressed LAS 1.4 content – achieving maximum compatibility with minimal disruption for users of ArcGIS, LASzip, and the larger LiDAR community,

Martin Isenburg, chief scientist and CEO of rapidlasso GmbH, was all smiles during the announement. “Yes, I had some hard feelings when hearing about their ‘LAZ clone‘ because our presumed open dialogue suddenly felt so very one-sided,” he said, “So over Martin Luther King weekend I proposed this LAS 1.4 trick as a joint development quoting MLK’s ‘We must accept finite disappointment, but never lose infinite hope’ and that seemed to resonate with them.” Speaking on the condition of anonymity an executive of Esri’s management added “For a global geospatial player like us it can happen that we do something ‘evil-by-accident’. We occasionally need someone like Martin to poke some good-natured fun at Esri to remind us of our values.”

LASeasy optimizes LAS files by reordering points along an adaptive space-filling curve for efficient LiDAR queries in the cloud. To access the corner of the LiDAR tile only the points shown in blue need to be loaded and decompressed.

LASeasy optimizes LAS files by reordering points along an adaptive space-filling curve for efficient LiDAR queries in the cloud. To access the corner of the LiDAR tile only the points shown in blue need to be loaded and decompressed.

Warming up for ILMF 2014, rapidlasso puts lean yet plush “LASlayers” on LiDAR

February 14, 2014
rapidlasso GmbH, Gilching, Germany

As a sweet foretaste to ILMF 2014, the creators of LAStoolsLASzip, and PulseWaves are announcing “LASlayers” already on Valentine’s Day. The new functionality nicely complements their popular and widely-used LiDAR compressor making the compressed LAZ files editable for most practical purposes. LASlayers significantly reduce I/O load for writing modification to LAS or LAZ files, especially when batch-processing LiDAR tiles on many cores in parallel or when sending changes to LiDAR files across bandwidth-limited networks.

Conceptually LASlayers add

LASlayers store modifications and additional  attributes to raw LAS or LAZ files in small LAY files avoiding to replicate data that has not changed.

Most point attributes (e.g. coordinates, intensities, scan angles, GPS times, etc.) are not modified when processing LiDAR. LASlayers avoids re-writing the unchanged portions of LAS or LAZ by storing only the actual differences layer by layer to a new “LAY” file. Changing the point classifications or deleting a few points, for example, can be done with LAY files that are just a tiny fraction of the size of a new LAS or LAZ file. Adding new attributes such as RGB colors or the height-above-ground with LASlayers means only this new information needs to be written.

This also provides simultaneous access to different versions of the data: a LiDAR server or a Web portal can store only a single copy of the raw LiDAR and apply LASlayers as needed on-the-fly, for example, to replace ellipsoidal with orthometric elevations or to add RGB colors.

Even users of other LiDAR processing software can readily take advantage of LASlayers with the new “laslayers.exe” tool that computes the difference between a raw and a modified LAS or LAZ file and expresses it as a LAY file (assuming the point order has not changed). A typical use case is the exchange of modifications to LiDAR files between remote locations such as a vendor in Australia or Canada and a data processing center in China or India. Instead of up- and downloading the entire modified LAS or LAZ files, only the much smaller LAY files need to be send back and forth.

A fully featured prototype of LASlayers is available (10 MB including data) together with three simple exercises that illustrate the concept and allow interested parties to test it already today on their own data.