liblwgeom, spatialite and GPL

[j.kn...@rocketmail.com]

Hello there,

I have a question regarding the compilation of spatialite with lwgeom:
- lwgeom is part of postgis and therefore GPL
- lwgeom can only be built as a static library

as far as I understand the GPL this means that upon compiling/linking spatialite together with lwgeom, spatialite also becomes GPL only (which is okay for spatialite as it is tri-licensed). But doesn't this then conflict when trying to use such spatialite with any other software/library which is not GPL e.g. when compiling gdal to use sqlite/spatialite ...? Then gdal will use spatialite which is now GPL and then GDAL suddenly is GPL (is this even possible?) which might inflict other software which uses gdal (that used to be X/MIT) ... etc. etc.? Shouldn't lwgeom be LGPL?

I'm a bit confused - can somebody help me? :)

Best,
 Jim

[a.fu...@lqt.it]

> I have a question regarding the compilation of spatialite with
> lwgeom:
> - lwgeom is part of postgis and therefore GPL
>

yes, true

> - lwgeom can only be built as a static library
>

seems to be true only on Windows; on Linux a shared library seems to
be created.
anyway: static or dynamic linkage has no relevance at all for GPL.

> as far as I understand the GPL this means that upon compiling/linking
> spatialite together with lwgeom, spatialite also becomes GPL only
> (which is okay for spatialite as it is tri-licensed).
>

yes, that's right

> But doesn't this then conflict when trying to use such spatialite
> with any
> other software/library which is not GPL e.g. when compiling gdal to
> use
> sqlite/spatialite ...?
>

I see no conflict at all; the GPL has a "viral/infective" clause.
so any further library or sw component linked to liblwgeom (either
statically or dynamically) will be immediately "infected", and will
automatically become GPLed.

anyway, you are obviously free to *not* enable liblwgeom at all;
spatialite supports the --disable-lwgeom configuration option exactly
for this reason.

> Then gdal will use spatialite which is now GPL
> and then GDAL suddenly is GPL (is this even possible?) which might
> inflict other software which uses gdal (that used to be X/MIT) ...
> etc. etc.?
>

the GPL "viral" clause always takes full precedence; if you decide
including a GPLed library, all the resulting sw will be GPLed.

please note: many GDAL pre-built distributions require GEOS support;
but GEOS is LGPLed, so the net result is that such distros are
implicitly
LGPLed, and aren't any longer X/MIT.

> Shouldn't lwgeom be LGPL?
>

I personally agree with your opinion: as a general rule adopting the
LGPL for any library seems to be more appropriate.
anyway, this mailing list obviously has no authority at all to discuss
this problem. You've eventually to ask this question to the PostGIS
developers.

bye Sandro

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[j.kn...@rocketmail.com]

Hello Sandro,

thanks for the quick reply.

I see no conflict at all; the GPL has a "viral/infective" clause.
so any further library or sw component linked to liblwgeom (either
statically or dynamically) will be immediately "infected", and will
automatically become GPLed.

anyway, you are obviously free to *not* enable liblwgeom at all;
spatialite supports the --disable-lwgeom configuration option exactly
for this reason.

Of course. On the other hand, the lwgeom features are interesting to have. :)
 

please note: many GDAL pre-built distributions require GEOS support;
but GEOS is LGPLed, so the net result is that such distros are
implicitly
LGPLed, and aren't any longer X/MIT.

I don't think that this holds in general: if it is dynamically linked, then it is not a derivative work and hence the LGPL does not apply to the "work that uses the Library" (https://en.wikipedia.org/wiki/GNU_Lesser_General_Public_License) - at least that's how I'm currently understanding LGPL

> Shouldn't lwgeom be LGPL?
>

I personally agree with your opinion: as a general rule adopting the
LGPL for any library seems to be more appropriate.
anyway, this mailing list obviously has no authority at all to discuss
this problem. You've eventually to ask this question to the PostGIS
developers.

Will do.

Best,
 Jim