[GRASS-dev] Re: Inclusion of r.surf.nnbathy in main svn: How to handle nn code ?

Hamish hamish_b at yahoo.com
Thu Sep 25 04:00:27 EDT 2008


Moritz Lennert wrote:
> As some of you will have seen a discussion was launched on the GRASS
> users list concerning the possible inclusion of r.surf.nnbathy into
> the main SVN.
> 
> However, the script needs Pavel Sakov's nn code. As Pavel changed jobs,
> the code is not available on the old web site anymore. However, he has
> sent me the code, and I've temporarily put it on my machine [1]. As 
....
> The question now is whether it would be possible to include the code
> directly into the GRASS tree. However, there seems to be a license
> issue:
> 
> Pavel Sakov wrote:
> > This question has been already discussed by GRASS developers a couple
> > of years ago, and the problem is the license of `triangle', which is
> > used for underlying Delaunay triangulation in `nn'. `triangle' is
> > freely available for non-commercial use only:

there is also the issue of the nnbathy license I asked about yesterday,
wrt transfer of copyright and the non-commercial use clause.
Does Pavel have the power to relicense his code as GPL?
If not, the user must always build it themselves regardless of the
status of triangle or a triangle replacement.


> > This is not a huge problem on its own. One could replace `triangle'
> > by `qhull', like it has been done some 5 years ago by Fernando Cardoso
> > (by memory) for integrating `nn' in Octave. However, `triangle' uses
> > exact arithmetics and never fails. Interpolating for DEMs, e.g. from
> > digitised contours creates a lot of numerically challenging
> > situations in regard to both triangulation and interpolation. I do
> > not know how robust qhull is in numerically extreme situations...

perhaps the recent Google SoC v.delaunay2 project by Martin Pavlovsky
could help here?
  http://trac.osgeo.org/grass/browser/grass-addons/vector/v.delaunay2


> > A quick way to proceed could be to maintain the
> > status-quo: host `nn' and let the end user decide
> > whether he can use `triangle' or not.

Unless the code is all GPL compatible I don't think we can host it on
the GRASS SVN or addons SVN. Perhaps at another OSGeo server or on
SourceForge? Personal websites are fine in the short term, but have a
habit of moving on after a few years and the code becomes lost.


Hamish



      



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