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Subject: Re: [geometry] snapshot of the future geometry 1.56 release
From: yohann.benedic_at_[hidden]
Date: 2014-02-28 09:53:29

Hi again,

Thank you for your answer. I tested your "rescale to integer" branch and it turns out it fixes quite a lot of things, great job :). In the end, it highlighted that some of my polygons are not simple, thus leading to further crashes in intersections, union_ and alike. I was wondering what was going to be my next step: is there (will there be) a predicate somewhere in boost::geometry that could help filter them out, or even better correct them beforehand? I am studying the Shamos-Hoey Algorithm as a good predicate algorithm on client code side, do you happen to have a better suggestion?

Thanks again for your time.

Yohann Bénédic
Wireless Engineering and Propagation
Research Engineer
tel. +33 384 544 338

-----Message d'origine-----
De : Geometry [mailto:geometry-bounces_at_[hidden]] De la part de Barend Gehrels
Envoyé : jeudi 27 février 2014 21:35
À : Boost.Geometry library mailing list
Objet : Re: [geometry] snapshot of the future geometry 1.56 release

Hi Yohann,

yohann.benedic_at_[hidden] wrote On 27-2-2014 16:44:
> Hi Barend,
> Sorry to bother you again. I am facing quite a large amount of crashes with either union_, or difference (and possibly others) when I try them on my large datasets (many hundred thousand polygons processed in various ways, I am actually porting existing working code from GPC to boost/Geometry). Most of what I see have to do with numerical robustness (e.g. computing the difference between two polygons that merely cover each other).
> The ported code is expected to become production code by the end of the semester and it's not going to happen with version 1.54.
> Since you told me a lot of work has been done about it in the future 1.56 release of boost::geometry, I was wondering if I could somehow try it (I believe I should download from to see how stable it has become regarding numerical robustness. The good thing would be that I could focus on reporting relevant crash cases and not the ones that are already fixed in your dev branch.
> What do you think? Is the link I found the right one for that matter?

It is not yet integrated into the "develop" branch. The branch is:

Apart from that the union and other intersection problems should be solved. However, a nasty side effect in some cases is that some spikes are left, I'm trying to fix that too and that is the reason why it is not integrated yet. I cannot say if that is a problem for you.

You are welcome to try it and report your experiences with it.

It is a (more or less) personal branch but still I try to have it as complete as possible, so no compilation errors etc, but it is not daily tested automatically.

Regards, Barend

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