Geometry Boost List: Re: [geometry] Accuray issue with geometry::difference() in version Boost 1.57

Subject: Re: [geometry] Accuray issue with geometry::difference() in version Boost 1.57
From: Mikkel B. Stegmann (mikkel.stegmann_at_[hidden])
Date: 2015-04-24 09:35:11

See below. Should this be elevated to a ticket?

Best regards,
Mikkel B. Stegmann

On 20/04/15 09:04, Mikkel B. Stegmann wrote:
>
> Dear Geometry list,
>
> the difference issue persists in v1.58. Apparently, it is related to 
> the rescaling policy introduced in v1.56 (if I read previous posts 
> correct). Although I'm reluctant to do so, I can mitigate the issue be 
> defining the BOOST_GEOMETRY_NO_ROBUSTNESS:
>
> difference polygon:  (249232.00000000003, 761089) (249232, 760980) 
> (265886.20000000001, 760980) (265886.20000000001, 729219) (94021, 
> 729219) (94021, 761089)
>
> Should this be elevated to a ticket?
>
> Best regards,
> Mikkel B. Stegmann
>
>
> On 17/04/15 10:47, Mikkel B. Stegmann wrote:
>> Hi Menalaos,
>>
>> somehow the results and code (including input data) got stripped in the
>> mail-version of my post. Here it is without raw-tags:
>>
>> Result using Boost v1.55:
>>
>>           249.232           761.09
>>           249.232           760.98
>>            265.89           760.98
>>            265.89          729.219
>>            94.021          729.219
>>            94.021           761.09
>>           249.232           761.09
>>
>>
>> Result using Boost v1.57:
>>
>> 249.232003466816           761.09
>>           249.232           760.98
>>            265.89 760.979984987659
>>            265.89          729.219
>>            94.021          729.219
>>            94.021           761.09
>> 249.232003466816           761.09
>>
>> ----
>>
>> #include <boost/foreach.hpp>
>> #include <boost/geometry/geometries/point_xy.hpp>
>> #include <boost/geometry.hpp>
>>
>> #include <cstdio>
>> #include <assert.h>
>>
>> int main() {
>>
>>    // 2D point with double precision
>>    typedef boost::geometry::model::d2::point_xy<double> BoostPoint;
>>
>>    // 2D polygon, ring type: clockwise, closed ("the first point must be
>> spatially equal to the last point")
>>    typedef boost::geometry::model::polygon<BoostPoint> BoostPolygon;
>>
>>    BoostPolygon rectangleA;
>>    rectangleA.outer().push_back(BoostPoint( 94.021, 729.219)); // 
>> clock-wise
>> points
>>    rectangleA.outer().push_back(BoostPoint( 94.021, 761.090));
>>    rectangleA.outer().push_back(BoostPoint(265.890, 761.090));
>>    rectangleA.outer().push_back(BoostPoint(265.890, 729.219));
>>    rectangleA.outer().push_back(BoostPoint( 94.021, 729.219)); // close
>>
>>    BoostPolygon rectangleB;
>>    rectangleB.outer().push_back(BoostPoint(249.232, 760.980)); // 
>> clock-wise
>> points
>>    rectangleB.outer().push_back(BoostPoint(249.232, 780.980));
>>    rectangleB.outer().push_back(BoostPoint(319.232, 780.980));
>>    rectangleB.outer().push_back(BoostPoint(319.232, 760.980));
>>    rectangleB.outer().push_back(BoostPoint(249.232, 760.980)); // close
>>
>>    std::list<BoostPolygon> differencePolygons;
>>    boost::geometry::difference(rectangleA, rectangleB, 
>> differencePolygons);
>>    assert(differencePolygons.size()==1);
>>
>>    BOOST_FOREACH(const BoostPoint &point, 
>> differencePolygons.front().outer())
>> {
>>      printf("%16.15g %16.15g\n", point.x(), point.y());
>>    }
>>
>>    return 0;
>> }
>>
>>
>>
>>
>> -- 
>> View this message in context: 
>> http://boost-geometry.203548.n3.nabble.com/Accuray-issue-with-geometry-difference-in-version-Boost-1-57-tp4026545p4026547.html
>> Sent from the Boost Geometry mailing list archive at Nabble.com.
>> _______________________________________________
>> Geometry mailing list
>> Geometry_at_[hidden]
>> http://lists.boost.org/mailman/listinfo.cgi/geometry
>
> _______________________________________________
> Geometry mailing list
> Geometry_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/geometry