[sf-lug] need advice: GPL licensing question

Rick Moen rick at linuxmafia.com
Thu Sep 13 12:00:32 PDT 2007

Quoting Catherine Jones (cathjone at eskimo.com):

> Just went to hear RMS and came away enlightened but confused.

You're really tempting me to say something unkind, catty, and unfair
about Richard frequently having that effect on people -- that's a heck
of a straight line -- but I'm going to try to resist.

Actually, I think you're just tripping over some slightly non-obvious
points of law.  I might be able to help.

> Here's my problem. I'm writing a textile-design program (pre-alpha
> tarball available at patternand.org) that the requires following to
> run:
> (1) my own Python code (released under GPL v3)
> (2) some files I wrote containing numerical data in XML format; this
>     data describes some sample polygons and ways to arrange them on a
>     flat surface - ideas that I believe (and hope) are common math
>     knowledge in the public domain

1.  Just a minor point in passing:  _ideas_ are not subject to copyright.
(They might in theory be patentable, if they can be used for practical
inventions.)  Copyright covers particular expressive (as opposed to
functional) elements within creative works.  

Collections of data thus are not considered creative works, and do not
give rise to copyright title.  So, that's your basic answer.[1]

If that's all you care about, stop reading here.  What follows is
related licensing/law geekery.

2.  When I say "give rise to", I'm referring to the way copyright
automatically comes into existence whenever you create any creative work 
"in fixed form", e.g., written down, in any of the eight categories of
creative work specified in the Copyright Act (literary works, musical
works, dramatic works, pantomimes and choreographic works, pictorial /
graphic / sculptural works, motion pictures, sound recordings, and
architectural works). 

In olden days, you couldn't own a copyright on a creative work without
it having a copyright statement, like "Copyright (C) Rick Moen 2007".
Then the USA joined an international treaty regime called the Berne
Convention on Copyrights, which changed that by making copyright title
pop into existence _automatically_ the moment you create a work in any
of the eight covered categories, and put it "in fixed form" (i.e., not
just in your head).

_But_ the important thing to note is that data collections, per se, have
never been regarded as creative works.  Hence, they never have had
copyright titles. (ownership interests).

3.  Merely putting two creative works together, e.g., on the same disk
drive, or using a program on a separate body of data, or on a separate
program, imposes no requirement, per se, that their licensing (if any)
be compatible.  According to copyright law, the owner of Work A's
copyright has no right to tell you what you may or may not do with Work
A in connection with someone else's Work B _unless_ you are creating a
"derivative work" based on Work A.  Creation of derivative works is a
right reserved by law to the copyright owner.  You need Work A's
permission to do that.

What's a "derivative work"?  That's a subtle question of law, and you'll
find some links in my http://linuxmafia.com/kb/Licensing_and_Law/
category, if you're interested.  To a first approximation, it means 
making a new creative Work B that includes substantive amounts of the
expressive (as opposed to purely functional) elements of copyrighted
Work A.  Either literal or non-literal copying can do this.

4.  But, anyway, if it's _your_ work, you needn't care if you're mixing
two works that you've issued to the public under incompatible licences,
because you don't need a licence to use your own works, and didn't need
to consent to the licence to get the ability to use them as you see fit.
So, even if there were a licence conflict between your GPLed program and
your dataset, that would not be a problem for _you_.  It would only be a
problem for any downstream recipients of that bundle (who, unlike you,
would not be the copyright owner).

[1]  Strictly speaking, only an attorney may lawfully answer your
question the way you posed it (i.e., give you legal advice on a specific 
real legal problem you have).  My remarks have therefore been about
generic points of law without saying specifically how they apply to your

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