Geometry Boost List: Re: [geometry] Bug again in boost::geometry::union_

Subject: Re: [geometry] Bug again in boost::geometry::union_
From: Barend Gehrels (barend_at_[hidden])
Date: 2014-02-08 07:39:35

Hi Sybren,

Sybren A. Stüvel wrote On 8-2-2014 0:11:
> Hi folks,
>
> This is my first post to this mailing list. I've just started to try 
> out Boost::Geometry. My goal is to replace CGAL (slow but robust) with 
> something faster. I'm trying to calculate the boundary polygon of the 
> projection of a triangulated mesh onto the ground plane (see 
> http://stuvel.eu/files/publication/2013-stuvel-occupancy_spaces-poster_mig2013.pdf). 
> For this I need to be able to calculate the union of several thousand 
> triangles in 2D.
>
> My code mostly works, except that sometimes all of a sudden the result 
> of a union_() call is empty, even though the two input-multi-polygons 
> are not, as described in 
> http://boost-geometry.203548.n3.nabble.com/Bug-again-in-boost-geometry-union-td4025831.html
>
> My question is this: what would be the quickest way to get the fixes 
> mentioned in that thread? I have a deadline for a paper this 
> wednesday. If I could get a workaround for this issue before that time 
> that would be awesome, as (when it runs) my Boost::Geometry code is 
> about 6x faster than when I use CGAL!

That is very good news! Thanks for your info and welcome to the list.

If you need it that soon, you need to use my git-branch where these 
problems have been fixed. It is not completely ready so I hope 
everything will work for you. If not, please report it such that I can 
at least have a quick look (though Wednesday is soon of course).

This is the branch:
https://github.com/boostorg/geometry/tree/rescale_to_integer

I hope to merge it to the development-branch soon.

Regards, Barend