Re: [Boost-users] How to use geometry::within with a polygon that encompasses a pole

Subject: Re: [Boost-users] How to use geometry::within with a polygon that encompasses a pole
From: Cameron Sabol (cameronsabol_at_[hidden])
Date: 2013-01-08 12:59:22

Yes, sorry for the typo. Example code should read:

   namespace bg = boost::geometry;
   typedef bg::model::point
       <
           double, 2, bg::cs::spherical_equatorial<bg::degree>
       > LonLatPoint;

   bg::model::polygon < LonLatPoint> northPoleBoundary;

   double lon = -180;
   while (lon <= 180)
   {
       bg::append(northPoleBoundary, LonLatPoint(lon, 88));
       lon += 5;
   }

   LonLatPoint northPole(0, 90);

   bool isInNorthPole = bg::within(northPole, northPoleBoundary);

Where result is isInNorthPole == false, but expected is isInNorthPole ==
true.

On Tue, Jan 8, 2013 at 12:26 PM, Michael Fawcett
<michael.fawcett_at_[hidden]>wrote:

> On Mon, Jan 7, 2013 at 5:20 PM, Cameron Sabol <cameronsabol_at_[hidden]>
> wrote:
> >
> > Hi,
> >
> > I'm have an issue with polygons from the geometry library using the
> spherical_equatorial coordinates when the polygon is meant to wrap a pole.
> >
> > e.g.
> >
> > namespace bg = boost::geometry;
> > typedef bg::model::point
> >     <
> >         double, 2, bg::cs::spherical_equatorial<bg::degree>
> >     > LonLatPoint;
> >
> > bg::model::polygon < LonLatPoint> northPoleBoundary;
> >
> >
> > double lon = -180;
> > while (lon <= 180)
> > {
> >     bg::append(northPoleBoundary, LonLatPoint(lon, 88));
> >     lon += 5;
> > }
> >
> > LonLatPoint northPole(90, 0);
> >
> > bool isInNorthPole = bg::within(northPole, northPoleBoundary);
> >
> > This code is giving me isInNorthPole == false. Am I constructing my
> polygon incorrectly? Is this a bug? Or is this behavior simply not
> implemented? Thanks for your help!
>
> I think you meant:
>
> LonLatPoint northPole(0, 90);
>
> --Mike
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