[GRASS5] GRASS connecting to external software

[Roger Bivand]

On Tue, 14 Mar 2006, Markus Neteler wrote:

> jan at intevation.de wrote:
> 
> >On Tuesday 14 March 2006 00:45, Markus Neteler wrote:
> >  
> >
> >>Let me ask again:
> >>
> >>how could a (say, fictive) project such GRASS-ABM, written
> >>in JAVA and not GPLed for whatsoever reason, make use of
> >>GRASS modules?
> >>
> >>I hope that the answer isn't: "use a proprietary GIS".
> >>    
> >>
> >
> >the answer should be: "GRASS-ABM should better go for a
> >GPL compatible license to take advantage of GRASS".
> >
> >I would like to see the GRASS team defend this and take
> >it as a strong benefit rather than trying to help others to keep
> >their developments separate from GRASS.
> >
> >The easier to use GRASS without being
> >GPL compatible the less contributions GRASS will receive
> >in the mid term.
> >
> >Does the benefit of GRASS-ABM using GRASS really weight
> >out this? I don't know.
> >  
> >
> It was an example for existing problems. I have spoken quite a few times to
> people who were interested to connect to GRASS, to invest even money into
> further GRASS development, but then went away since this didn't want to
> or could not (because they were not owner) publish their piece of software
> under GPL.
> 
> More users = more developers, for sure. And we definitely need more
> developers.
> 
> >>In my opinion we should work on a solution for this
> >>problem.
> >>    
> >>
> >
> >Tell GRASS-ABM that they should either think about a GPL
> >compatible license or on some "bridging" layers under a GPL compatible
> >license. The latter is sort of a grey area, but depending on
> >the actual needs of GRASS-ABM there can be practical solutions.
> >  
> >
> That's why I try to push the SWIG interface idea. But I am not sure if this
> works as a (legal) bridge.

The summary here:

http://news.hping.org/comp.lang.python.archive/35539.html

looks positive, I think you are on the right track. It's about "copying, 
distribution or modification of GPLed code", and if the interface doesn't, 
it should help. In the quoted summary:

"Our approach to thsi issue has been to instruct end users to obtain third
party GPLed code from its original source, and to install both it and our
non-GPLed code (it is Mozilla licensed) on their system. In that way what
we are doing cannot possibly be construed as "copying, distributing or
modifying" that third-party GPLed code. Rather, our code just calls it at
run-time on the end user's system."

and:

"... if your non-GPLed SWIG source code needs to use GPLed header files,
there is nothing to stop you distributing your code to an end user, and
then instructing the end user to download the GPLed coded needed by your
non-GPLed code, and to then compile everything, all within teh confines of
their system. Provided that the end results of this compilation are not
then distributed to anyone else, then the GPL is not violated, not in
letter nor in spirit."

For "distribution" this is awkward, but is possible. As the note says, GPL 
is not worried about use outside of "copying, distribution and 
modification".

Roger

> 
> Markus
> 
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no