
Geometry : 
Subject: Re: [geometry] Union clipping not working
From: Barend Gehrels (barend_at_[hidden])
Date: 20131029 06:47:43
Hi Hunk,
> you are right
>
> I registered my type only as Ring not as polygon.
>
> It is possible to set my own polygon with my ring type? For environment ccw
> directed and for obstacles cw?
>
> Is there an easy way to register my rings as polygon?
Yes. But not macro. Because of the interior rings, this is more complex. See e.g.
http://www.boost.org/doc/libs/1_54_0/libs/geometry/doc/html/geometry/examples.html also recently discussed on this list.
>
> I only want to know if the union polygon gets a hole or not
Why then not use boost::geometry::model::polygon, as output.
Another option ( trick) is doing an intersection too. If p and q are areas of input rings, and i and u are areas of intersection and union, u = p + q  i. If that does not hold, the union must have a hole.
Regards, Barend
Sent from iPad
>
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