Geometry Boost List: Re: [geometry] Problems performing boolean operations on polygons with shared edges

Subject: Re: [geometry] Problems performing boolean operations on polygons with shared edges
From: Barend Gehrels (barend_at_[hidden])
Date: 2016-04-20 11:26:35

Hi Oleg,

Op 14-4-2016 om 0:54 schreef Oleg Evseev:
> Hi, Barend!
>
> I've tried to use boost 1.61.0 beta for my case. And instead of 
> getting problems with zero areas, I'm getting really wrong result - 
> union ignore one of the mpolygons (without exceptions). I created 
> ticket with WKT https://svn.boost.org/trac/boost/ticket/12125
>
> Illustration: https://s16.postimg.org/9wcp31ik5/union+1.61.0+bug.png
> appended mpolygon (the red one - two trinangles) is ignored. union 
> result is equal to current path (the yellow one - two trinangles)
>
> Maybe this is caused by the shared point of two trinangels in one 
> multipolygon?
>

Thanks for the reports. It is indeed not solved yet. I updated the 
tickets. It is caused somehow by the precision and need some further 
study. We plan to change the details of the implementation w.r.t. 
precision/rescaling for one of the coming versions. Hopefully asap of 
course, but these things take a longer time.

Regards, Barend