Re: [boost] [geometry] Querying for Points nearest to a Segment.

Subject: Re: [boost] [geometry] Querying for Points nearest to a Segment.
From: Adam Wulkiewicz (adam.wulkiewicz_at_[hidden])
Date: 2014-07-28 21:46:28

2014-07-29 3:07 GMT+02:00 Jeremy Murphy <jeremy.william.murphy_at_[hidden]>:

> Veering slightly off topic but still related to Geometry development, I've
> hit some hurdles with the rtree index.  I could create an index of points
> easily but then couldn't query for the nearest neighbour of a segment.  (I
> assume this is simply not supported at present; is it forthcoming?)  So I
> created a ring or polygon from the segment and tried to query for the
> points that it covers/intersects, which is a feature listed in the
> documentation, but I've hit this compilation error:
>
>
> /usr/include/boost/geometry/algorithms/detail/overlay/get_turn_info.hpp:932:32:
> error: no matching function for call to
> ‘boost::geometry::model::referring_segment<const
> boost::geometry::model::d2::point_xy<double> >::referring_segment(const
> boost::geometry::model::point<double, 2ul,
> boost::geometry::cs::cartesian>&, const
> boost::geometry::model::point<double, 2ul,
> boost::geometry::cs::cartesian>&)’
>
> This constructor for referring_segment looks OK to me, except maybe for the
> 'const' qualifier on the arguments?
>

Which version of Boost are you using?
Indeed nearest(segment, ...) shouldn't work in 1.55.
However intersects(ring_or_poly) should. Could you prepare some minimal
failing example?

E.g. this compiles for me, using develop branch (upcomming 1.56) or 1.55
without one, marked line:

#include <boost/geometry.hpp>
#include <boost/geometry/index/rtree.hpp>
#include <boost/geometry/geometries/segment.hpp>
#include <boost/geometry/geometries/ring.hpp>

namespace bg = boost::geometry;
namespace bgi = bg::index;

typedef bg::model::point<double, 2, bg::cs::cartesian> P;
typedef bg::model::segment<P> Seg;
typedef bg::model::ring<P> Ring;
typedef bg::model::polygon<P> Poly;
typedef P V;

int main()
{
    typedef bgi::rtree<V, bgi::linear<16, 4> > RT;
    //typedef bgi::rtree<V, bgi::quadratic<16, 4> > RT;
    //typedef bgi::rtree<V, bgi::rstar<16, 4> > RT;

    RT rt;
    V v;

    rt.query(bgi::nearest(Seg(), 1), &v); // Using 1.55 without this line
    rt.query(bgi::intersects(Ring()), &v);
    rt.query(bgi::intersects(Poly()), &v);
}

Regards,
Adam