[postgis-users] liblwgeom and LGPL?

Paul Ramsey pramsey at opengeo.org
Fri Mar 29 11:05:12 PDT 2013


On the licensing issue: PostGIS is GPL. Liblwgeom is part of PostGIS.
Liblwgeom is GPL. That's not going to change.

On the discomfort issue: Spatialite deciding to make Liblwgeom an
(optional?) dependency has the effect of causing the Spatialite
license regime for people who activate the option. For existing users
of Spatialite, I can imagine that would be a disconcerting
development. And the consequence for them is, they will have to
remember to not activate the Liblwgeom option in their build from now
on, or learn to live with the GPL.

You have accidentally mis-stated the effect of the PostGIS/Liblwgeom
GPLv2 license when you said "If you don't change the library you are
free to use it in your own program without that program becoming GPL."
Those are the terms of the *L*GPL, not the GPL. If you use Liblwgeom
in your program, your program must conform to the GPL, which means
that *if you distribute it*, you must also distribute the source. Note
that the GPL does not require you to *publish* your source, it
requires you to include the source when you distribute the program:
organizations just often find that publishing is more cost and space
effective than including source in distribution.

P.

On Thu, Mar 28, 2013 at 6:12 PM, Brian H Wilson <brian at wildsong.biz> wrote:
> This thread is veering off topic and I feel responsible. I am an ardent
> supporter of GPL, open source, and PostGIS.
> I was trying to explain how a "traditional" software company might react to
> a shift in licensing. I promote open source, I contribute to it when I can.
> So far I have not been able to convince my traditional employer to open
> source things I have done for him, but I am getting much closer. My attitude
> is "give back, and help it get even better."
>
> But let's drop that part -- Jim's ORIGINAL question was (in part)
>
>
> " Which means, that when I want to link lwgeom to another piece of software
> (I'm thinking of spatialite here), this again needs to be GPL and when I
> then want to link spatialite together with e.g. gdal this again becomes GPL
> etc. etc. -- "
>
> MY understanding is that you can use GPL libraries without making your
> derived program GPL -- spatialite or GDAL in this case -- see the "GPL
> licensing exception". This gets into the whole GPL V1/V2/V3 thing. Which
> license covers liblwgeom? It looks like it's GPL V2. Parts are under more
> permissive licenses. (eg GDAL).
>
> From the wikipedia page: http://en.wikipedia.org/wiki/GPL_linking_exception
>
> " Craig Mundie, Microsoft Senior Vice President has described the GPL as
> being "viral".[81] Mundie argues that the GPL has a "viral" effect in that
> it only allows the conveyance of whole programs, which means programs that
> link to GPL libraries must themselves be under a GPL-compatible license,
> else they cannot be combined and distributed.
>
> In the views of Richard Stallman, Mundie's metaphor of a "virus" is wrong as
> software under the GPL does not "attack" or "infect" other software.
> Stallman believes that comparing the GPL to a virus is an extremely
> unfriendly thing to say, and that a better metaphor for software under the
> GPL would be a spider plant: If one takes a piece of it and puts it
> somewhere else, it grows there too.[82][83][84]"
>
> Spatialite itself is also GPL V2 _or_ LGPL _or_ Mozilla Public license. I
> consider this a little confusing but I am not worried! They just want to
> make it easy for you to use and prevent it from being locked up or patented.
>
> I think the real answer to Jim is "no" -- if you create a work that uses
> spatialite and liblwgeom as libraries then you are working entirely within
> the framework spelled out by GPL V2. Go for it! Is there someone (Paul
> Ramsey? PostGIS foundation?) who can make this unequivocal?  If you don't
> change the library you are free to use it in your own program without that
> program becoming GPL.
>
> When I use open source code in a library and I make a change to the library,
> I always send the change back.
>
> Personally I want people to use the work I do, so my own leaning is towards
> licenses like X/MIT, Apache, BSD and so on that are not confusing. As in:
> "Do anything you want with this. If you break it you can keep both pieces."
>
> Gotta go, spouse dragging me away from computer for family dinner, cheers --
>
> Brian
>
>
>
>
>
>
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