geos::operation::polygonize::Polygonizer Class Reference

Polygonizes a set of Geometrys which contain linework that represents the edges of a planar graph. More...

#include <Polygonizer.h>

Collaboration diagram for geos::operation::polygonize::Polygonizer:

Classes
class	LineStringAdder

Public Member Functions
	Polygonizer (bool onlyPolygonal=false)
	Create a Polygonizer with the same GeometryFactory as the input Geometrys. More...
	~Polygonizer ()=default
void	add (std::vector< geom::Geometry * > *geomList)
	Add a collection of geometries to be polygonized. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted and used. More...
void	add (std::vector< const geom::Geometry * > *geomList)
	Add a collection of geometries to be polygonized. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted and used. More...
void	add (geom::Geometry *g)
void	add (const geom::Geometry *g)
std::vector< std::unique_ptr< geom::Polygon > >	getPolygons ()
	Gets the list of polygons formed by the polygonization. More...
const std::vector< const geom::LineString * > &	getDangles ()
	Get the list of dangling lines found during polygonization. More...
bool	hasDangles ()
const std::vector< const geom::LineString * > &	getCutEdges ()
	Get the list of cut edges found during polygonization. More...
bool	hasCutEdges ()
const std::vector< std::unique_ptr< geom::LineString > > &	getInvalidRingLines ()
	Get the list of lines forming invalid rings found during polygonization. More...
bool	hasInvalidRingLines ()
bool	allInputsFormPolygons ()

Protected Attributes
std::unique_ptr< PolygonizeGraph >	graph
std::vector< const geom::LineString * >	dangles
std::vector< const geom::LineString * >	cutEdges
std::vector< std::unique_ptr< geom::LineString > >	invalidRingLines
std::vector< EdgeRing * >	holeList
std::vector< EdgeRing * >	shellList
std::vector< std::unique_ptr< geom::Polygon > >	polyList

Private Member Functions
void	add (const geom::LineString *line)
void	polygonize ()
void	findShellsAndHoles (const std::vector< EdgeRing * > &edgeRingList)
void	findDisjointShells ()

Static Private Member Functions
static void	findValidRings (const std::vector< EdgeRing * > &edgeRingList, std::vector< EdgeRing * > &validEdgeRingList, std::vector< std::unique_ptr< geom::LineString >> &invalidRingList)
static void	findOuterShells (std::vector< EdgeRing * > &shellList)
static std::vector< std::unique_ptr< geom::Polygon > >	extractPolygons (std::vector< EdgeRing * > &shellList, bool includeAll)

Private Attributes
LineStringAdder	lineStringAdder
bool	extractOnlyPolygonal
bool	computed

Friends
class	Polygonizer::LineStringAdder

Detailed Description

Polygonizes a set of Geometrys which contain linework that represents the edges of a planar graph.

All types of Geometry are accepted as input; the constituent linework is extracted as the edges to be polygonized. The edges must be correctly noded; that is, they must only meet at their endpoints. Polygonization will accept incorrectly noded input but will not form polygons from non-noded edges, and reports them as errors.

The Polygonizer reports the follow kinds of errors:

• Dangles - edges which have one or both ends which are not incident on another edge endpoint
• Cut Edges - edges which are connected at both ends but which do not form part of a polygon

• Invalid Ring Lines - edges which form rings which are invalid (e.g. the component lines contain a self-intersection)

  The Polygonizer constructor allows extracting only polygons which form a valid polygonal result. The set of extracted polygons is guaranteed to be edge-disjoint. This is useful when it is known that the input lines form a valid polygonal geometry (which may include holes or nested polygons).

Definition at line 83 of file Polygonizer.h.

Constructor & Destructor Documentation

geos::operation::polygonize::Polygonizer::Polygonizer ( bool  onlyPolygonal = false )

explicit

Create a Polygonizer with the same GeometryFactory as the input Geometrys.

Parameters

onlyPolygonal

true if only polygons which form a valid polygonal geometry should be extracted

geos::operation::polygonize::Polygonizer::~Polygonizer ( )

default

Member Function Documentation

void geos::operation::polygonize::Polygonizer::add ( const geom::LineString *  line )

private

Add a linestring to the graph of polygon edges.

Parameters

line	the LineString to add

void geos::operation::polygonize::Polygonizer::add

(

std::vector< geom::Geometry * > *

geomList

)

Add a collection of geometries to be polygonized. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted and used.

Parameters

geomList

a list of Geometry with linework to be polygonized

void geos::operation::polygonize::Polygonizer::add

(

std::vector< const geom::Geometry * > *

geomList

)

Add a collection of geometries to be polygonized. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted and used.

Parameters

geomList

a list of Geometry with linework to be polygonized

void geos::operation::polygonize::Polygonizer::add

(

geom::Geometry *

g

)

Add a geometry to the linework to be polygonized. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted and used

Parameters

g	a Geometry with linework to be polygonized

void geos::operation::polygonize::Polygonizer::add

(

const geom::Geometry *

g

)

Add a geometry to the linework to be polygonized. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted and used

Parameters

g	a Geometry with linework to be polygonized

bool geos::operation::polygonize::Polygonizer::allInputsFormPolygons

(

)

static std::vector<std::unique_ptr<geom::Polygon> > geos::operation::polygonize::Polygonizer::extractPolygons ( std::vector< EdgeRing * > &  shellList, bool  includeAll  )

staticprivate

void geos::operation::polygonize::Polygonizer::findDisjointShells ( )

private

static void geos::operation::polygonize::Polygonizer::findOuterShells ( std::vector< EdgeRing * > &  shellList )

staticprivate

void geos::operation::polygonize::Polygonizer::findShellsAndHoles ( const std::vector< EdgeRing * > &  edgeRingList )

private

static void geos::operation::polygonize::Polygonizer::findValidRings ( const std::vector< EdgeRing * > &  edgeRingList, std::vector< EdgeRing * > &  validEdgeRingList, std::vector< std::unique_ptr< geom::LineString >> &  invalidRingList  )

staticprivate

const std::vector<const geom::LineString*>& geos::operation::polygonize::Polygonizer::getCutEdges

(

)

Get the list of cut edges found during polygonization.

Returns

a (possibly empty) collection of pointers to the input LineStrings which are cut edges.

const std::vector<const geom::LineString*>& geos::operation::polygonize::Polygonizer::getDangles

(

)

Get the list of dangling lines found during polygonization.

Returns

a (possibly empty) collection of pointers to the input LineStrings which are dangles.

const std::vector<std::unique_ptr<geom::LineString> >& geos::operation::polygonize::Polygonizer::getInvalidRingLines

(

)

Get the list of lines forming invalid rings found during polygonization.

Returns

a (possibly empty) collection of pointers to the input LineStrings which form invalid rings

std::vector<std::unique_ptr<geom::Polygon> > geos::operation::polygonize::Polygonizer::getPolygons

(

)

Gets the list of polygons formed by the polygonization.

Ownership of vector is transferred to caller, subsequent calls will return NULL.

Returns

a collection of Polygons

bool geos::operation::polygonize::Polygonizer::hasCutEdges

(

)

bool geos::operation::polygonize::Polygonizer::hasDangles

(

)

bool geos::operation::polygonize::Polygonizer::hasInvalidRingLines

(

)

void geos::operation::polygonize::Polygonizer::polygonize ( )

private

Perform the polygonization, if it has not already been carried out.

Friends And Related Function Documentation

friend class Polygonizer::LineStringAdder

friend

Definition at line 237 of file Polygonizer.h.

Member Data Documentation

bool geos::operation::polygonize::Polygonizer::computed

private

Definition at line 124 of file Polygonizer.h.

std::vector<const geom::LineString*> geos::operation::polygonize::Polygonizer::cutEdges

protected

Definition at line 132 of file Polygonizer.h.

std::vector<const geom::LineString*> geos::operation::polygonize::Polygonizer::dangles

protected

Definition at line 131 of file Polygonizer.h.

bool geos::operation::polygonize::Polygonizer::extractOnlyPolygonal

private

Definition at line 123 of file Polygonizer.h.

std::unique_ptr<PolygonizeGraph> geos::operation::polygonize::Polygonizer::graph

protected

Definition at line 128 of file Polygonizer.h.

std::vector<EdgeRing*> geos::operation::polygonize::Polygonizer::holeList

protected

Definition at line 135 of file Polygonizer.h.

std::vector<std::unique_ptr<geom::LineString> > geos::operation::polygonize::Polygonizer::invalidRingLines

protected

Definition at line 133 of file Polygonizer.h.

LineStringAdder geos::operation::polygonize::Polygonizer::lineStringAdder

private

Definition at line 97 of file Polygonizer.h.

std::vector<std::unique_ptr<geom::Polygon> > geos::operation::polygonize::Polygonizer::polyList

protected

Definition at line 137 of file Polygonizer.h.

std::vector<EdgeRing*> geos::operation::polygonize::Polygonizer::shellList

protected

Definition at line 136 of file Polygonizer.h.

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

• Polygonizer.h