[OSGeo-Standards] Please review: Open Letter asking to avoid format fragmentation in LiDAR standards

Sat Apr 11 06:24:16 PDT 2015

Has ESRI explained why they are creating a new format? In reading the
discussion so far it sounds like there is an assumption that the issue is
with FastAC, but there may be other reasons. And is the ESRI format open?

ESRI has created a new format for Geocon datum grid shift files that seems
like a significant improvement over the original. Their github pages [1] offers
a logical explanation of why they are creating a new format, a useful set
of tools, and an Apache license.

[1] https://github.com/Esri/geocon-file-routines

Rich

On Sat, Apr 11, 2015 at 6:43 AM, Sebastiaan Couwenberg <sebastic at xs4all.nl>
wrote:

> On 04/11/2015 01:19 PM, Even Rouault wrote:
> > Le samedi 11 avril 2015 12:18:39, Sebastiaan Couwenberg a écrit :
> >> On 04/11/2015 09:24 AM, Cameron Shorter wrote:
> >>> I forgot to share URL:
> >>> http://wiki.osgeo.org/wiki/LIDAR_Format_Letter
> >>
> >> Are you aware of the legal issue in LASzip which likely contributed to
> >> ESRI developing their own alternative?
> >>
> >> LASzip contains code from the FastAC algorithm which allows distribution
> >> but not modification.
> >>
> >> The FastAC license is therefor incompatible with the LGPL-2.1+ license
> >> used for LASzip which guarantees the right to modification.
> >
> > I believed the LGPL only guarantees the right to modification to the
> source
> > code that is licenced under LGPL, or am I wrong ? LGPL can (and does) put
> > constraints on code that uses it, but why/how could it put constraints
> on code
> > it uses ?
>
> The LGPL-2.1+ [1] defines a library as follows:
>
> "
>  A "library" means a collection of software functions and/or data
>  prepared so as to be conveniently linked with application programs
>  (which use some of those functions and data) to form executables.
>
>  The "Library", below, refers to any such software library or work
>  which has been distributed under these terms.  A "work based on the
>  Library" means either the Library or any derivative work under
>  copyright law: that is to say, a work containing the Library or a
>  portion of it, either verbatim or with modifications and/or translated
>  straightforwardly into another language.  (Hereinafter, translation is
>  included without limitation in the term "modification".)
> "
>
> [1] http://spdx.org/licenses/LGPL-2.1+
>
> The FastAC code in LASzip is part of the "collection of software
> functions" and therefor considered integral part of the library.
>
> The LGPL guarantees the right to modify "any portion" of the library:
>
> "
>  2. You may modify your copy or copies of the Library or any portion
>  of it, thus forming a work based on the Library, and copy and
>  distribute such modifications or work under the terms of Section 1
>  above, provided that you also meet all of these conditions:
>
>     a) The modified work must itself be a software library.
>
>     b) You must cause the files modified to carry prominent notices
>     stating that you changed the files and the date of any change.
>
>     c) You must cause the whole of the work to be licensed at no
>     charge to all third parties under the terms of this License.
>
>     d) If a facility in the modified Library refers to a function or a
>     table of data to be supplied by an application program that uses
>     the facility, other than as an argument passed when the facility
>     is invoked, then you must make a good faith effort to ensure that,
>     in the event an application does not supply such function or
>     table, the facility still operates, and performs whatever part of
>     its purpose remains meaningful.
>
>     (For example, a function in a library to compute square roots has
>     a purpose that is entirely well-defined independent of the
>     application.  Therefore, Subsection 2d requires that any
>     application-supplied function or table used by this function must
>     be optional: if the application does not supply it, the square
>     root function must still compute square roots.)
> "
>
> The license for the FastAC portion does not allow modification making it
> incompatible with LGPL.
>
> The changes made to the FastAC source code included in LASzip can also
> be considered a violation of the FastAC license. But since those changes
> are quite minimal it can be argued that the FastAC terms do not apply,
> only a court ruling can settle this argument.
>
> Since the FastAC authors would like their work to be used in open source
> projects they are unlikely to make a case about the modifications made
> to their code in LASzip, but it's entirely within their rights under the
> current license terms.
>
> The FastAC terms make LASzip undistributable because the LGPL gives
> permissions to recipients of the library to modify it and disallows
> restricting these rights:
>
> "
>  10. Each time you redistribute the Library (or any work based on the
>  Library), the recipient automatically receives a license from the
>  original licensor to copy, distribute, link with or modify the Library
>  subject to these terms and conditions.  You may not impose any further
>  restrictions on the recipients' exercise of the rights granted herein.
>  You are not responsible for enforcing compliance by third parties with
>  this License.
> "
>
> The FastAC license does restrict these rights in violation of this clause.
>
> > Similar situation: I can write GPL/LGPL code that works on Windows and
> links
> > against Windows system libraries, which don't give right to
> modification, but
> > it doesn't invalidate the fact that I chose GPL/LGPL license for my code
> and
> > doesn't prevent anyone using it under their terms.
>
> The license for the Windows libraries are leading in this example, if
> their license terms contains a clause like the LGPL about a "work that
> uses the Library" those terms are applicable to the GPL/LGPL code that
> use the Windows libraries.
>
> > For Debian, I can understand that it doesn't want to distribute code
> licensed
> > with free license that uses code with a not-free license. But from the
> point
> > of view of a proprietary software editor, if you don't need to make any
> > modification to the FastAC code, what's the issue ?
>
> As explained above the LGPL allows modification of "any portion", which
> in the case of LASzip is not applicable, because the FastAC portion does
> not allow modification. This is the root of the problem.
>
> A proprietary software vendor needs to comply with the Free Software
> licenses of the works it includes in their product. GPL licensed works
> are out of the question because inclusion of only portions of the code
> makes their entire product the GPL code is included in a derivative work
> to which the terms of the GPL apply.
>
> The proprietary software vendor can only include LGPL licensed works
> because only linking to the library does not make their product a
> derivative work of the library. If they make modifications to the LGPL
> licensed work, those modifications do fall under the LGPL license and
> therefore require source code for the modification be made available.
>
> The current FastAC license doesn't allow that portion to be modified,
> preventing anyone from making improvements. If the FastAC code was
> freely licensed, ESRI could have improved the algorithm instead of being
> forced to develope an alternative for example.
>
> Kind Regards,
>
> Bas
>
> --
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-- 
Richard W. Greenwood, PLS
www.greenwoodmap.com
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