[OSGeo-Discuss] GIS_Libraries

[Christopher Schmidt]

On Tue, May 05, 2009 at 11:24:47AM -0500, P Kishor wrote:
> On Tue, May 5, 2009 at 11:06 AM, Daniel Ames <amesdani at isu.edu> wrote:
> > Nenad,
> > The OSGeo projects use a variety of licenses. You'll see LGPL, MPL, GPL,
> > MIT, and others. If you are developing commercial tools, you'll need to
> > avoid GPL (someone correct me if I'm wrong.)
> 
> ----
> Disclaimer: IANAL. Get legal advice from your lawyer before embarking
> on your million dollar enterprise.
> ----
> 
> I'll correct you, because, as stated above, you are misrepresenting at
> best, and wrong at worst. ;-)
> 
> GPL does not prevent you from making money. GPL only requires that if
> you modify the code that is under GPL, then you must redistribute the
> modified code under GPL. Granted this may not be easy to figure out in
> real world scenarios, but consider the following --
> 
> Let's say ShapeLib is published under GPL (I don't know whether or not
> it is; this is only for illustration purpose). Let's say, MapServer
> utilizes ShapeLib, but doesn't modify ShapeLib, but uses ShapeLib as
> is. Let's say, MapServer's creator decides to make millions off of
> MapServer, Inc. He is under no obligation to release the source code
> of MapServer, but he is obligated to release the source code of
> ShapeLib, which is no big deal, because the source code of ShapeLib is
> already available to anyone.
> 
> On the other hand, let's say, ShapeLib is modified to perform better,
> or differently, for MapServer. Now, there is an obligation to release
> the source code to the modified version of ShapeLib no matter what the
> value of that value-added might be. That is what the GPL obligates.
> MapServer itself is still governed by whatever license that its
> creator decides to apply.

Er, I think you're confusing the GPL and the LGPL. What you have just
described is the situation with the LGPL, but not with GPL.

Because MapServer integrates ShapeLib (I'm assuming from your
description above that it does) then MapServer is also required to be
released under the GPL, because shapelib is linked to MapServer.
MapServer -- as it is linking ShapeLib -- is *also* required to be
released under the terms of the GPL, even if the MapServer code itself
was not.

(For the record, no part of shapelib or MapServer is released under the
GPL, to the best of my knowledge, so this is simply a straw man, not a
practical discussion.)

Any time your code includes GPL code, all of the code that incorporates
it must also be treated under the GPL.

This does *not* prevent you from making money. It simply means you also
have to give source code to the people you give object code to, and that
they are then able to do the same to others, if they choose to do so.
Red Hat makes a large amount of money by doing exactly this, for example
-- though they don't make money off giving you the software, and it
seems unlikely that much software can be 'sold' when it's under the GPL.
(It's not impossible, though -- especially when things like 'compiling
on Windows' come in to play.)

Regards,
-- 
Christopher Schmidt
Web Developer