Considering GEOS

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Considering GEOS

Mateusz Loskot
Administrator
Hi,

When I found GGL and started to work with it, I got an idea of porting
some of GEOS [1] algorithms to GGL. GEOS is licensed under the terms of
LGPL. I decided to discuss [2] a bit if there is possibly some
compatibility with Boost License, to confirm there is even a point of
thinking of this. It looks it's not easy to answer such question
and there are potential problems and conflicts on the level of law.

Perhaps you will find the discussion interesting.

[1] http://trac.osgeo.org/geos/
[2] http://lists.osgeo.org/pipermail/geos-devel/2009-April/thread.html
--
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
--
Mateusz Loskot
http://mateusz.loskot.net
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Considering GEOS

Barend Gehrels
Hi Mateusz,

> When I found GGL and started to work with it, I got an idea of porting
> some of GEOS [1] algorithms to GGL.
Actually I had seen that and had to think about it. Personally I don't
think it is really useful to us. Our approach is totally different from
theirs. In the past I've looked to some implementations (not GEOS but
e.g. geometryalgorithms). It is possible but in the end they turn out to
be completely rewritten. It is justed an "influence" like reading an
article.

Besides that I'm afraid that if we "copy" GEOS code we'll also get (a
part of) its performance.

Finally there is the license issue.

It might seem attractive because they have much more (= all OGC)
operations implemented. However, if we continue the step of the new
segment intersection, together with the (completely revised) steps in
the polygon clip (Weiler Atherton graph traversal), we have
touch,overlaps,intersects,relate,disjoint,equals,intersection,union and
buffer all implemented so it then becomes really useful. More about this
will follow.

Barend



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Considering GEOS

Mateusz Loskot
Administrator
Barend Gehrels wrote:
> Hi Mateusz,
>
>> When I found GGL and started to work with it, I got an idea of
>> porting some of GEOS [1] algorithms to GGL.
>
> Actually I had seen that and had to think about it. Personally I
> don't think it is really useful to us. Our approach is totally
> different from theirs.

Yes, I'm aware of that.

> In the past I've looked to some implementations (not GEOS but e.g.
> geometryalgorithms). It is possible but in the end they turn out to
> be completely rewritten. It is justed an "influence" like reading an
> article.

I've been thinking of looking at some solutions,
constructions, algorithms and re-implement them completely,
according to GGL approach.

> Besides that I'm afraid that if we "copy" GEOS code we'll also get (a
>  part of) its performance.

It is possible.

> Finally there is the license issue.

Right.

> It might seem attractive because they have much more (= all OGC)
> operations implemented. However, if we continue the step of the new
> segment intersection, together with the (completely revised) steps in
>  the polygon clip (Weiler Atherton graph traversal), we have
> touch,overlaps,intersects,relate,disjoint,equals,intersection,union
> and buffer all implemented so it then becomes really useful.

Absolutely, I can see this potential.

> More about this will follow.

OK, no rush.

Best regards,
--
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
--
Mateusz Loskot
http://mateusz.loskot.net
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