Computes an approximate intersection of two line segments by taking the most central of the endpoints of the segments. More...

#include <CentralEndpointIntersector.h>

Collaboration diagram for geos::algorithm::CentralEndpointIntersector:

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Public Member Functions
	CentralEndpointIntersector (const geom::Coordinate &p00, const geom::Coordinate &p01, const geom::Coordinate &p10, const geom::Coordinate &p11)

const geom::Coordinate &	getIntersection () const

Static Public Member Functions
static const geom::Coordinate &	getIntersection (const geom::Coordinate &p00, const geom::Coordinate &p01, const geom::Coordinate &p10, const geom::Coordinate &p11)

Private Member Functions
void	compute ()

geom::Coordinate	findNearestPoint (const geom::Coordinate &p, const std::vector< geom::Coordinate > &pts) const

Static Private Member Functions
static geom::Coordinate	average (const std::vector< geom::Coordinate > &pts)

Private Attributes
std::vector< geom::Coordinate >	_pts

geom::Coordinate	_intPt

Detailed Description

Computes an approximate intersection of two line segments by taking the most central of the endpoints of the segments.

This is effective in cases where the segments are nearly parallel and should intersect at an endpoint. It is also a reasonable strategy for cases where the endpoint of one segment lies on or almost on the interior of another one. Taking the most central endpoint ensures that the computed intersection point lies in the envelope of the segments. Also, by always returning one of the input points, this should result in reducing segment fragmentation. Intended to be used as a last resort for computing ill-conditioned intersection situations which cause other methods to fail.

Author: Martin Davis

Version: 1.8

Definition at line 62 of file CentralEndpointIntersector.h.

Constructor & Destructor Documentation

geos::algorithm::CentralEndpointIntersector::CentralEndpointIntersector	(	const geom::Coordinate &	p00,
		const geom::Coordinate &	p01,
		const geom::Coordinate &	p10,
		const geom::Coordinate &	p11
	)

inline

Definition at line 75 of file CentralEndpointIntersector.h.

Member Function Documentation

static geom::Coordinate geos::algorithm::CentralEndpointIntersector::average ( const std::vector< geom::Coordinate > & pts )

inlinestaticprivate

Definition at line 112 of file CentralEndpointIntersector.h.

References geos::geom::Coordinate::x, and geos::geom::Coordinate::y.

void geos::algorithm::CentralEndpointIntersector::compute ( )

inlineprivate

Definition at line 105 of file CentralEndpointIntersector.h.

geom::Coordinate geos::algorithm::CentralEndpointIntersector::findNearestPoint	(	const geom::Coordinate &	p,
		const std::vector< geom::Coordinate > &	pts
	)		const

inlineprivate

Determines a point closest to the given point.

Parameters

p	the point to compare against
p1	a potential result point
p2	a potential result point
q1	a potential result point
q2	a potential result point

Returns: the point closest to the input point p

Definition at line 140 of file CentralEndpointIntersector.h.

References geos::geom::Coordinate::distanceSquared(), and geos::geom::Coordinate::getNull().

Here is the call graph for this function:

static const geom::Coordinate& geos::algorithm::CentralEndpointIntersector::getIntersection	(	const geom::Coordinate &	p00,
		const geom::Coordinate &	p01,
		const geom::Coordinate &	p10,
		const geom::Coordinate &	p11
	)