id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
9828	boost::geometry::union_(...) creates redundant closing point	Volker Schöch <vschoech@…>	Barend Gehrels	"Polygons created by boost::geometry algorithms should conform to the same rules as the input. In the following example, boost::geometry::union_ takes two simple, non-empty rectangular polygons and creates a polygon with a redundant closing point. My polygon type is oriented '''counter-clockwise''' and '''not closed''', my point type is based on '''int'''.

This is the data used as input to union:
{{{
_TPolygon<int> const polygon =
	_TPolygon<int>(""MULTIPOLYGON(((3398 1759,3592 1759,3592 1893,3398 1893)))"")
	| _TPolygon<int>( ""MULTIPOLYGON(((3592 1893,3592 1759,3910 1759,3910 1893)))"" );
}}}

This is the resulting multi-polygon with the redundant closing point:
{{{
MULTIPOLYGON(((3592 1893,3398 1893,3398 1759,3592 1759,3910 1759,3910 1893,3592 1893)))
}}}

This is my code that wraps boost::geometry to implement the operator used above:
{{{
template<typename T>
template<typename Geometry>
_TPolygon< T > _TPolygon< T >::operator|(Geometry const& geometry) const
{
	_TPolygon< T > polygonOut;
	boost::geometry::union_(*this, geometry, polygonOut);

	// the following line fixes the problem but should not be necessary
	//boost::geometry::correct( polygonOut );

	return polygonOut;
}
}}}
"	Bugs	closed	Boost 1.56.0	geometry	Boost 1.55.0	Problem	fixed	union, multi-polygon, polygon, correct	mkaravel