[Proj] Geo Transfoms and calculations

Charles Wilson proj at cwilson.fastmail.fm
Mon Jan 5 23:29:25 EST 2009

Charles Karney wrote:
> Gerald I. Evenden wrote:
>> 5.  What's a poor jerk like me supposed to do?  For example, on the
>> geodetic program I am currently finishing up I want to put 'readline'
>> on the front end for obvious reasons; BUT wait, that uses GPL.  Arrgh!
>> I can hear the bitching and moaning now.  At the moment I have a
>> simple procedure called 'readline' as a substitute but gee, is the
>> name possible copyrighted too?

There's a similar BSD-licensed library called editline, which is a
"autotool- and libtoolized port of the NetBSD Editline library
(libedit)." In addition to its own native el_* interface, it provides a
mostly-complete implementation of the rl_* readline interface in


It depends on lib[n]curses or libtermcap (but then, so does readline

> A commercial entity which wants to incorporate your code into its
> proprietary code will need to find a substitute for the GPL library, of
> course.  Or, as you noted, you might provide a lame substitute yourself
> (a dummy version of readline or simple-minded implementations of GSL
> functions).

Legally Gerald can do anything he wants -- including weave GSL so
tightly into proj that for all intents and purposes proj becomes defacto
GPL -- even if its own intrinsic code is nominally MIT.

However, there are a lot of commercial entities which currently use the
proj library.  Gerald is graciously being considerate of the needs of
existing users, and is trying to find a workable middle ground that
doesn't impose too much of a burden on his limited time (e.g. no
re-inventing the GSL wheel), but doesn't heavily limit existing
commercial users (so, only judicious use of GSL/readline in
#ifdef-outable ways).  My hope is that these #ifdef-out sections don't
grow to encompass large swaths of existing proj functionality -- but
it's only a hope.

People have always complained about the divide between the permissive
open-source and copy-left communities, ever since RMS invented the
latter. That won't change...and the divide won't go away -- and it's
hard to straddle the boundary.  Gerald is just the latest voice to join
the chorus.


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