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

[Moritz Lennert]

Hello,

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 
Pavel says:

> This is a mature code, developed since 1999 or 2000. I do not expect much development other than
> fixing occasional bugs, which are reported at a rate < 1 / year (incidentally, I am fixing a minor bug right now).
> 
> I will be very happy if you could host this library. Just let me know how to submit an upgrade when it becomes available.

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:

On 24/09/08 10:34, 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:
> 
> "Distribution of this code as part of a commercial system is permissible ONLY BY DIRECT ARRANGEMENT
> WITH THE AUTHOR."
> 
> 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...
> 
> 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.

Any suggestions on how to deal with this ?

Moritz