[Proj] libproj4 license and related hassles

Frank Warmerdam warmerdam at pobox.com
Thu Nov 13 13:39:04 EST 2008

Gerald I. Evenden wrote:
> The GPL dilemma will arise again as I embark on building a better proj/lproj 
> mouse trap but in this case software requiring GPL licensed material is a 
> critical element of the program and cannot be simply edited out.
> My last comment relates to my pausing on the Wikipedia page related to the MIT 
> license ( http://en.wikipedia.org/wiki/MIT_license ) and the comment in the 
> second paragraph stating thst the MIT license is "GPL-compatible."  Not being 
> a lawyer I am note sure that I understand all of the ramification but I am 
> going to stop worrying about future encounters with GPL and consider any 
> problems between libproj4 and GPL non-existant.


Obviously you can do whatever you want.  But if you add non-optional
dependencies on GPL libraries to libproj4, then it essentially makes it
impossible for the library to be used in proprietary applications.
This in turn makes it difficult for me to ever make my hoped-for leap to
using libproj4 for my underlying projections support and just handling
stuff like datum shifting, coordinate system dictionaries and so forth
in what I currently call PROJ.4.

I will say that when the time comes there is nothing preventing someone
else for taking on the task of developing non-GPL replacements for the
components in question (or reworking libproj4 a bit to make them optional).
So, in that sense, using a GPL library now does not mean that libproj4 is
forever stuck using the library.

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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