
Geometry : 
Subject: Re: [geometry] Why closure?
From: Barend Gehrels (barend_at_[hidden])
Date: 20130620 12:00:22
Hi,
On 2062013 11:26, TONGARI wrote:
>
> I'm not quite understand why we need traits::closure for Ring &
> Polygon, aren't these always closed?
> What should I expect if the closure is open? Should I see Ring as
> Linestring then?
No (about the last question).
Apparently the doc about closure should be updated. However, this page
explains it clearly:
So we support "open" and "closed" polygon/rings. For a triangle, an open
polygon/ring contains 3 points, the 3 points of the triangle. For a
closed polygon/ring, it contains 4 points, where the last point should
be identical to the first point.
Regards, Barend
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