Computes the geometric overlay of two Geometry. More...

#include <OverlayOp.h>

Inheritance diagram for geos::operation::overlay::OverlayOp:

Public Types
enum	OpCode { opINTERSECTION = 1 , opUNION = 2 , opDIFFERENCE = 3 , opSYMDIFFERENCE = 4 }
	The spatial functions supported by this class. More...

Public Member Functions
	OverlayOp (const geom::Geometry g0, const geom::Geometry g1)
	Construct an OverlayOp with the given Geometry args. More...

geom::Geometry *	getResultGeometry (OpCode overlayOpCode)
	Gets the result of the overlay for a given overlay operation. More...

geomgraph::PlanarGraph &	getGraph ()
	Gets the graph constructed to compute the overlay. More...

bool	isCoveredByLA (const geom::Coordinate &coord)
	This method is used to decide if a point node should be included in the result or not. More...

bool	isCoveredByA (const geom::Coordinate &coord)
	This method is used to decide if an L edge should be included in the result or not. More...

Public Member Functions inherited from geos::operation::GeometryGraphOperation
	GeometryGraphOperation (const geom::Geometry g0, const geom::Geometry g1)

	GeometryGraphOperation (const geom::Geometry g0, const geom::Geometry g1, const algorithm::BoundaryNodeRule &boundaryNodeRule)

	GeometryGraphOperation (const geom::Geometry *g0)

const geom::Geometry *	getArgGeometry (unsigned int i) const

Static Public Member Functions
static geom::Geometry *	overlayOp (const geom::Geometry geom0, const geom::Geometry geom1, OpCode opCode)
	Computes an overlay operation for the given geometry arguments. More...

static bool	isResultOfOp (const geomgraph::Label &label, OpCode opCode)
	Tests whether a point with a given topological Label relative to two geometries is contained in the result of overlaying the geometries using a given overlay operation. More...

static bool	isResultOfOp (geom::Location loc0, geom::Location loc1, OpCode opCode)
	This method will handle arguments of Location.NULL correctly. More...

static std::unique_ptr< geom::Geometry >	createEmptyResult (OverlayOp::OpCode overlayOpCode, const geom::Geometry a, const geom::Geometry b, const geom::GeometryFactory *geomFact)

Protected Member Functions
void	insertUniqueEdge (geomgraph::Edge *e)
	Insert an edge from one of the noded input graphs. More...

Protected Member Functions inherited from geos::operation::GeometryGraphOperation
void	setComputationPrecision (const geom::PrecisionModel *pm)

Additional Inherited Members
Protected Attributes inherited from geos::operation::GeometryGraphOperation
algorithm::LineIntersector	li

const geom::PrecisionModel *	resultPrecisionModel

std::vector< geomgraph::GeometryGraph * >	arg
	The operation args into an array so they can be accessed by index.

Detailed Description

Computes the geometric overlay of two Geometry.

The overlay can be used to determine any boolean combination of the geometries.

Member Enumeration Documentation

◆ OpCode

enum geos::operation::overlay::OverlayOp::OpCode

The spatial functions supported by this class.

These operations implement various boolean combinations of the resultants of the overlay.

Enumerator
opINTERSECTION	The code for the Intersection overlay operation.
opUNION	The code for the Union overlay operation.
opDIFFERENCE	The code for the Difference overlay operation.
opSYMDIFFERENCE	The code for the Symmetric Difference overlay operation.

Constructor & Destructor Documentation

◆ OverlayOp()

geos::operation::overlay::OverlayOp::OverlayOp	(	const geom::Geometry *	g0,
		const geom::Geometry *	g1
	)

Construct an OverlayOp with the given Geometry args.

Ownership of passed args will remain to caller, and the OverlayOp won't change them in any way.

Member Function Documentation

◆ createEmptyResult()

static std::unique_ptr< geom::Geometry > geos::operation::overlay::OverlayOp::createEmptyResult	(	OverlayOp::OpCode	overlayOpCode,
		const geom::Geometry *	a,
		const geom::Geometry *	b,
		const geom::GeometryFactory *	geomFact
	)

static

Creates an empty result geometry of the appropriate dimension, based on the given overlay operation and the dimensions of the inputs. The created geometry is always an atomic geometry, not a collection.

The empty result is constructed using the following rules:

opINTERSECTION result has the dimension of the lowest input dimension
opUNION - result has the dimension of the highest input dimension
opDIFFERENCE - result has the dimension of the left-hand input
opSYMDIFFERENCE - result has the dimension of the highest input dimension

◆ getGraph()

geomgraph::PlanarGraph & geos::operation::overlay::OverlayOp::getGraph ( )

inline

Gets the graph constructed to compute the overlay.

Returns: the overlay graph

◆ getResultGeometry()

geom::Geometry * geos::operation::overlay::OverlayOp::getResultGeometry ( OpCode overlayOpCode )

Gets the result of the overlay for a given overlay operation.

Note: this method can be called once only.

Parameters

overlayOpCode the overlay operation to perform

Returns: the compute result geometry

Exceptions

TopologyException if a robustness problem is encountered

◆ insertUniqueEdge()

void geos::operation::overlay::OverlayOp::insertUniqueEdge ( geomgraph::Edge * e )

protected

Insert an edge from one of the noded input graphs.

Checks edges that are inserted to see if an identical edge already exists. If so, the edge is not inserted, but its label is merged with the existing edge.

◆ isCoveredByA()

bool geos::operation::overlay::OverlayOp::isCoveredByA ( const geom::Coordinate & coord )

This method is used to decide if an L edge should be included in the result or not.

Returns: true if the coord point is covered by a result Area geometry

◆ isCoveredByLA()

bool geos::operation::overlay::OverlayOp::isCoveredByLA ( const geom::Coordinate & coord )

This method is used to decide if a point node should be included in the result or not.

Returns: true if the coord point is covered by a result Line or Area geometry

◆ isResultOfOp() [1/2]

static bool geos::operation::overlay::OverlayOp::isResultOfOp	(	const geomgraph::Label &	label,
		OpCode	opCode
	)

static

Tests whether a point with a given topological Label relative to two geometries is contained in the result of overlaying the geometries using a given overlay operation.

The method handles arguments of Location::NONE correctly

Parameters

label	the topological label of the point
opCode	the code for the overlay operation to test

Returns: true if the label locations correspond to the overlayOpCode

◆ isResultOfOp() [2/2]

static bool geos::operation::overlay::OverlayOp::isResultOfOp	(	geom::Location	loc0,
		geom::Location	loc1,
		OpCode	opCode
	)

static

This method will handle arguments of Location.NULL correctly.

Returns: true if the locations correspond to the opCode

◆ overlayOp()

static geom::Geometry * geos::operation::overlay::OverlayOp::overlayOp	(	const geom::Geometry *	geom0,
		const geom::Geometry *	geom1,
		OpCode	opCode
	)

static

Computes an overlay operation for the given geometry arguments.

Parameters

geom0	the first geometry argument
geom1	the second geometry argument
opCode	the code for the desired overlay operation

Returns: the result of the overlay operation

Exceptions

TopologyException if a robustness problem is encountered

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

OverlayOp.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ OpCode

Constructor & Destructor Documentation

◆ OverlayOp()

Member Function Documentation

◆ createEmptyResult()

◆ getGraph()

◆ getResultGeometry()

◆ insertUniqueEdge()

◆ isCoveredByA()

◆ isCoveredByLA()

◆ isResultOfOp() [1/2]

◆ isResultOfOp() [2/2]

◆ overlayOp()