Snaps the vertices and segments of a LineString to a set of target snap vertices. More...

#include <LineStringSnapper.h>

Public Member Functions
	LineStringSnapper (const geom::Coordinate::Vect &nSrcPts, double nSnapTol)

std::unique_ptr< geom::Coordinate::Vect >	snapTo (const geom::Coordinate::ConstVect &snapPts)

void	setAllowSnappingToSourceVertices (bool allow)

Private Member Functions
void	snapVertices (geom::CoordinateList &srcCoords, const geom::Coordinate::ConstVect &snapPts)

geom::Coordinate::ConstVect::const_iterator	findSnapForVertex (const geom::Coordinate &pt, const geom::Coordinate::ConstVect &snapPts)

void	snapSegments (geom::CoordinateList &srcCoords, const geom::Coordinate::ConstVect &snapPts)
	Snap segments of the source to nearby snap vertices. More...

geom::CoordinateList::iterator	findSegmentToSnap (const geom::Coordinate &snapPt, geom::CoordinateList::iterator from, geom::CoordinateList::iterator too_far)
	Finds a src segment which snaps to (is close to) the given snap point. More...

geom::CoordinateList::iterator	findVertexToSnap (const geom::Coordinate &snapPt, geom::CoordinateList::iterator from, geom::CoordinateList::iterator too_far)

	LineStringSnapper (const LineStringSnapper &other)=delete

LineStringSnapper &	operator= (const LineStringSnapper &rhs)=delete

Private Attributes
const geom::Coordinate::Vect &	srcPts

double	snapTolerance

bool	allowSnappingToSourceVertices

bool	isClosed

Detailed Description

Snaps the vertices and segments of a LineString to a set of target snap vertices.

A snapping distance tolerance is used to control where snapping is performed.

Definition at line 51 of file LineStringSnapper.h.

Constructor & Destructor Documentation

geos::operation::overlay::snap::LineStringSnapper::LineStringSnapper	(	const geom::Coordinate::Vect &	nSrcPts,
		double	nSnapTol
	)

inline

Creates a new snapper using the given points as source points to be snapped.

Parameters

nSrcPts	the points to snap
nSnapTol	the snap tolerance to use

Definition at line 62 of file LineStringSnapper.h.

geos::operation::overlay::snap::LineStringSnapper::LineStringSnapper ( const LineStringSnapper & other )

privatedelete

Member Function Documentation

geom::CoordinateList::iterator geos::operation::overlay::snap::LineStringSnapper::findSegmentToSnap	(	const geom::Coordinate &	snapPt,
		geom::CoordinateList::iterator	from,
		geom::CoordinateList::iterator	too_far
	)

private

Finds a src segment which snaps to (is close to) the given snap point.

Only a single segment is selected for snapping. This prevents multiple segments snapping to the same snap vertex, which would almost certainly cause invalid geometry to be created. (The heuristic approach to snapping used here is really only appropriate when snap pts snap to a unique spot on the src geometry.)

Also, if the snap vertex occurs as a vertex in the src coordinate list, no snapping is performed (may be changed using setAllowSnappingToSourceVertices).

Parameters

from	an iterator to first point of first segment to be checked
too_far	an iterator to last point of last segment to be checked

Returns: an iterator to the snapped segment or too_far if no segment needs snapping (either none within snapTol distance, or one found on the snapPt)

geom::Coordinate::ConstVect::const_iterator geos::operation::overlay::snap::LineStringSnapper::findSnapForVertex	(	const geom::Coordinate &	pt,
		const geom::Coordinate::ConstVect &	snapPts
	)

private

geom::CoordinateList::iterator geos::operation::overlay::snap::LineStringSnapper::findVertexToSnap	(	const geom::Coordinate &	snapPt,
		geom::CoordinateList::iterator	from,
		geom::CoordinateList::iterator	too_far
	)

private

LineStringSnapper& geos::operation::overlay::snap::LineStringSnapper::operator= ( const LineStringSnapper & rhs )

privatedelete

void geos::operation::overlay::snap::LineStringSnapper::setAllowSnappingToSourceVertices ( bool allow )

inline

Definition at line 77 of file LineStringSnapper.h.

void geos::operation::overlay::snap::LineStringSnapper::snapSegments	(	geom::CoordinateList &	srcCoords,
		const geom::Coordinate::ConstVect &	snapPts
	)

private

Snap segments of the source to nearby snap vertices.

Source segments are "cracked" at a snap vertex. A single input segment may be snapped several times to different snap vertices.

For each distinct snap vertex, at most one source segment is snapped to. This prevents "cracking" multiple segments at the same point, which would likely cause topology collapse when being used on polygonal linework.

Parameters

srcCoords	the coordinates of the source linestring to be snapped the object will be modified (coords snapped)
snapPts	the target snap vertices

std::unique_ptr<geom::Coordinate::Vect> geos::operation::overlay::snap::LineStringSnapper::snapTo ( const geom::Coordinate::ConstVect & snapPts )

void geos::operation::overlay::snap::LineStringSnapper::snapVertices	(	geom::CoordinateList &	srcCoords,
		const geom::Coordinate::ConstVect &	snapPts
	)

private

Member Data Documentation

bool geos::operation::overlay::snap::LineStringSnapper::allowSnappingToSourceVertices

private

Definition at line 88 of file LineStringSnapper.h.

bool geos::operation::overlay::snap::LineStringSnapper::isClosed

private

Definition at line 89 of file LineStringSnapper.h.

double geos::operation::overlay::snap::LineStringSnapper::snapTolerance

private

Definition at line 86 of file LineStringSnapper.h.

const geom::Coordinate::Vect& geos::operation::overlay::snap::LineStringSnapper::srcPts

private

Definition at line 84 of file LineStringSnapper.h.

The documentation for this class was generated from the following file:

LineStringSnapper.h

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation