[Kstars-devel] VSOP data and the GPL

[Jason Harris]

Hello,

On Wednesday 25 January 2006 02:18, Mike McGavin wrote:
> I noticed that KStars includes some VSOP87 catalogue data in the
> source tree.  I was hoping somebody could clarify the state of VSOP87
> data and the GPL.
Seems like we go through this for all of our data files, so here we go 
again. :)  Seriously, though, thanks for bringing it up, we want to be sure 
we're doing the right thing.

> I sent a query to the CDS service for astronomical catalogues, which
> distributes the VSOP87 data online.  I've included the full response
> from Sebastien Derriere at the CDS at the end of this post.  To
> summarise, though, he said I was allowed to redistribute the data
> freely, as long as I acknowledged the source, and as long as it was
> *not* distributed under the GPL.  (Note that he's speaking more on
> behalf of the CDS than the copyright holders, I think.)
That is a really weird answer for them to give you.  I have asked them about 
usage of other catalogs before, and never got that answer.  I suppose they 
are worried about the data being modified.  

> I'm certainly not a GPL lawyer, but my understanding was that this
> would make the VSOP87 data incompatible with the GPL, at least if
> obtained via the CDS.  
Yes, that seems clear from the answer given.

> If it's incompatible, it could complicate 
> matters when it comes to distributing the VSOP87 data in GPL'd
> software which (if I understand the correctly) would require
> re-releasing the data under the GPL.
You could distribute the data separatelly, but that's not very user-friendly.

> It's occurred to me that the data might easily have been released in a
> GPL-compatible way through some other path that didn't involve the
> CDS, such as directly from the copyright holders.  
That is in fact the case for us.  We got the VSOP87 data from NASA's 
Astronomical Data Center, which catalogs electronic versions of data tables 
from astronomy journals (just like the CDS; in fact the CDS was originally a 
mirror of ADC).  However, unlike the CDS, ADC explicitly puts the data they 
publish into the public domain:
http://adc.gsfc.nasa.gov/adc/questions_feedback.html#policies

I would send you the link to ADC's publication of the VSOP87 data, but 
unfortunately, NASA got out of this business in 2002.  They now simply 
provide a link to CDS for data tables!  It's really frustrating that CDS is 
publishing the data with restrictions.  As the ADC said in the above FAQ, 
"The data are for scientific use only and have no commercial value."

> It's also occurred 
> to me that raw data such as that in the VSOP87 and other catalogues
> might not be legally copyrightable in the way that the response to my
> query implied, although I'm not personally qualified to judge this.
> I'm not aware of either of these possibilities, but I'm also not sure
> where to start looking for them.
Yeah, we've had similar thoughts as these kinds of issues came up.  Genrally, 
we've tried to err on the side of caution.  It does seem like we spend a lot 
of effort accomodating people that are asserting some level of ownership over 
the laws of physics. :(

So, you have a couple of options:

(1) obtain the VSOP87 data from KStars.  I puposefully left off any copyright 
information on these files, because I got them from the public domain via the 
ADC, and as far as I am concerned, they are still in the public domain.

(2) contact the authors and explain the situation.  A quick google search 
turned up this site: http://www.bdl.fr/imcce_en.html, which the authors seem 
to be associated with somehow.  They publish the VSOP data on their FTP 
server:  ftp://ftp.imcce.fr/pub/ephem/planets/vsop87
but the README contains no information on copyright or usage.  It does, 
however, give the email addresses of the authors.
My guess is that they will tell you to go ahead and use the data (and won't 
understand what the fuss is about). 

I have a friend at CDS; he was the person I asked about GPL usage a few years 
ago.  He said he was pushing for an explicit allowance for GPL projects at 
that time.  Maybe I'll contact him again to see what happened.

Hope that helps,
Jason

-- 
Jason Harris
jharris at 30doradus.org