[Proj] libproj4 license and related hassles

Peter S Galbraith psg at debian.org
Thu Nov 13 14:45:57 EST 2008

Gerald I. Evenden <geraldi.evenden at gmail.com> wrote:

> Again, cries of dismay occured when I used the GSL in solving the
> inverse projection problem.  Again, my usage of the library was based
> upon using better material than I could code up without a great deal
> of effort and time.  Why reinvent the wheel? 

Because it's not your wheel.  You have admitted that it is good code
that you can use without any great effort or time.  The cost of using it
is that you respect the license of its author.  If you don't want to
license libproj under the GPL (which is perfectly fine!), then don't use
a GPL'ed library.

> 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.

Unfortunately "Ignorance of the law is not an excuse for breaking the

The MIT license is GPL-compatible in one way only.  You can take MIT
licensed materiel and add it to GPL'ed code (to create a larger code
under the GPL), but you can't take GPL'ed code and add it to MIT code
(to create a larger code licensed under the MIT license).

Hope this helps...


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