#include <OverlayNG.h>

Public Member Functions
	OverlayNG (const geom::Geometry geom0, const geom::Geometry geom1, const geom::GeometryFactory *p_geomFact, int p_opCode)

	OverlayNG (const geom::Geometry geom0, const geom::Geometry geom1, const geom::PrecisionModel *p_pm, int p_opCode)

	OverlayNG (const geom::Geometry geom0, const geom::Geometry geom1, int p_opCode)

	OverlayNG (const geom::Geometry geom0, const geom::PrecisionModel p_pm)

void	setOptimized (bool p_isOptimized)

void	setStrictMode (bool p_isStrictMode)

void	setAreaResultOnly (bool p_areaResultOnly)

void	setOutputEdges (bool p_isOutputEdges)

void	setOutputResultEdges (bool p_isOutputResultEdges)

void	setNoder (noding::Noder *p_noder)

void	setOutputNodedEdges (bool p_isOutputNodedEdges)

std::unique_ptr< Geometry >	getResult ()

Static Public Member Functions
static bool	isResultOfOpPoint (const OverlayLabel *label, int opCode)

static bool	isResultOfOp (int overlayOpCode, Location loc0, Location loc1)

static std::unique_ptr< Geometry >	overlay (const Geometry geom0, const Geometry geom1, int opCode, const PrecisionModel *pm)

static std::unique_ptr< Geometry >	overlay (const Geometry geom0, const Geometry geom1, int opCode, const PrecisionModel pm, noding::Noder noder)

static std::unique_ptr< Geometry >	overlay (const Geometry geom0, const Geometry geom1, int opCode, noding::Noder *noder)

static std::unique_ptr< Geometry >	overlay (const Geometry geom0, const Geometry geom1, int opCode)

static std::unique_ptr< Geometry >	geomunion (const Geometry geom, const PrecisionModel pm)

static std::unique_ptr< Geometry >	geomunion (const Geometry geom, const PrecisionModel pm, noding::Noder *noder)

Static Public Attributes
static constexpr bool	STRICT_MODE_DEFAULT = false

static constexpr int	INTERSECTION = 1

static constexpr int	UNION = 2

static constexpr int	DIFFERENCE = 3

static constexpr int	SYMDIFFERENCE = 4

Detailed Description

Computes the geometric overlay of two geom::Geometrys, using an explicit precision model to allow robust computation. The overlay can be used to determine any of the following set-theoretic operations (boolean combinations) of the geometries:

INTERSECTION - all points which lie in both geometries
UNION - all points which lie in at least one geometry
DIFFERENCE - all points which lie in the first geometry but not the second
SYMDIFFERENCE - all points which lie in one geometry but not both

The requirements for overlay input are:

Input collections must be homogeneous (all elements must have the same dimension).
Inputs may be simple link GeometryCollections. A GeometryCollection is simple if it can be flattened into a valid Multi-geometry; i.e. it is homogeneous and does not contain any overlapping Polygons.
In general, inputs must be valid geometries. However, polygonal inputs may contain the following two kinds of "mild" invalid topology: (i) rings which self-touch at discrete points (sometimes called inverted shells and exverted holes). (ii) rings which touch along line segments (i.e. topology collapse).

The precision model used for the computation can be supplied independent of the precision model of the input geometry. The main use for this is to allow using a fixed precision for geometry with a floating precision model. This does two things: ensures robust computation; and forces the output to be validly rounded to the precision model.

For fixed precision models noding is performed using a noding::snapround::SnapRoundingNoder. This provides robust computation (as long as precision is limited to around 13 decimal digits).

For floating precision an noding::MCIndexNoder is used. This is not fully robust, so can sometimes result in util::TopologyExceptions being thrown. For robust full-precision overlay see OverlayNGRobust.

Note: If a noding::snap::SnappingNoder is used it is best to specify a fairly small snap tolerance, since the intersection clipping optimization can interact with the snapping to alter the result.

Optionally the overlay computation can process using strict mode (via setStrictMode(boolean). In strict mode result semantics are:

Lines and Points resulting from topology collapses are not included in the result
Result geometry is homogeneous for the INTERSECTION and DIFFERENCE operations.
Result geometry is homogeneous for the UNION and SYMDIFFERENCE operations if the inputs have the same dimension.

Strict mode has the following benefits:

Results are simpler
Overlay operations are chainable without needing to remove lower-dimension elements

The original JTS overlay semantics correspond to non-strict mode.

If a robustness error occurs, a TopologyException is thrown. These are usually caused by numerical rounding causing the noding output to not be fully noded. For robust computation with full-precision OverlayNGRobust can be used.

Author: mdavis

See also: OverlayNGRobust

Constructor & Destructor Documentation

◆ OverlayNG() [1/3]

geos::operation::overlayng::OverlayNG::OverlayNG	(	const geom::Geometry *	geom0,
		const geom::Geometry *	geom1,
		const geom::GeometryFactory *	p_geomFact,
		int	p_opCode
	)

inline

Creates an overlay operation on the given geometries, with a defined precision model. The noding strategy is determined by the precision model.

◆ OverlayNG() [2/3]

geos::operation::overlayng::OverlayNG::OverlayNG	(	const geom::Geometry *	geom0,
		const geom::Geometry *	geom1,
		const geom::PrecisionModel *	p_pm,
		int	p_opCode
	)

inline

Creates an overlay operation on the given geometries, with a defined precision model. The noding strategy is determined by the precision model.

◆ OverlayNG() [3/3]

geos::operation::overlayng::OverlayNG::OverlayNG	(	const geom::Geometry *	geom0,
		const geom::Geometry *	geom1,
		int	p_opCode
	)

inline

Creates an overlay operation on the given geometries using the precision model of the geometries.

The noder is chosen according to the precision model specified.

For PrecisionModel#FIXED a snap-rounding noder is used, and the computation is robust.
For PrecisionModel#FLOATING a non-snapping noder is used, and this computation may not be robust. If errors occur a util::TopologyException is thrown.

Member Function Documentation

◆ geomunion() [1/2]

static std::unique_ptr< Geometry > geos::operation::overlayng::OverlayNG::geomunion	(	const Geometry *	geom,
		const PrecisionModel *	pm
	)

static

Computes a union operation on the given geometry, with the supplied precision model. The primary use for this is to perform precision reduction (round the geometry to the supplied precision).

The input must be a valid geometry. Collections must be homogeneous. IMPORTANT: You probably want OverlayNGUnaryUnion, not this.

Parameters

geom	the geometry
pm	the precision model to use

Returns: the result of the union operation

See also: OverlayMixedPoints; PrecisionReducer; UnaryUnionNG; CoverageUnion

◆ geomunion() [2/2]

static std::unique_ptr< Geometry > geos::operation::overlayng::OverlayNG::geomunion	(	const Geometry *	geom,
		const PrecisionModel *	pm,
		noding::Noder *	noder
	)

static

Computes a union of a single geometry using a custom noder.

The primary use of this is to support coverage union.

The input must be a valid geometry. Collections must be homogeneous. IMPORTANT: You probably want OverlayNGUnaryUnion, not this.

Parameters

geom	the geometry to union
pm	the precision model to use (maybe be null)
noder	the noder to use

Returns: the result geometry

See also: CoverageUnion

◆ getResult()

std::unique_ptr< Geometry > geos::operation::overlayng::OverlayNG::getResult ( )

Gets the result of the overlay operation.

Returns: the result of the overlay operation.

Exceptions

IllegalArgumentException	if the input is not supported (e.g. a mixed-dimension geometry)
TopologyException	if a robustness error occurs

◆ isResultOfOp()

static bool geos::operation::overlayng::OverlayNG::isResultOfOp	(	int	overlayOpCode,
		Location	loc0,
		Location	loc1
	)

static

Tests whether a point with given geom::Locations relative to two geometries would be contained in the result of overlaying the geometries using a given overlay operation. This is used to determine whether components computed during the overlay process should be included in the result geometry.

The method handles arguments of geom::Location::NONE correctly.

◆ isResultOfOpPoint()

static bool geos::operation::overlayng::OverlayNG::isResultOfOpPoint	(	const OverlayLabel *	label,
		int	opCode
	)

static

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

The method handles arguments of geom::Location::NONE correctly

◆ overlay() [1/4]

static std::unique_ptr< Geometry > geos::operation::overlayng::OverlayNG::overlay	(	const Geometry *	geom0,
		const Geometry *	geom1,
		int	opCode
	)

static

Computes an overlay operation on the given geometry operands, using the precision model of the geometry. and an appropriate noder.

The noder is chosen according to the precision model specified.

For geom::PrecisionModel#FIXED a snap-rounding noder is used, and the computation is robust.
For geom::PrecisionModel#FLOATING a non-snapping noder is used, and this computation may not be robust. If errors occur a util::TopologyException is thrown.

Parameters

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

Returns: the result of the overlay operation

◆ overlay() [2/4]

static std::unique_ptr< Geometry > geos::operation::overlayng::OverlayNG::overlay	(	const Geometry *	geom0,
		const Geometry *	geom1,
		int	opCode,
		const PrecisionModel *	pm
	)

static

Computes an overlay operation for the given geometry operands, with the noding strategy determined by the precision model.

Parameters

geom0	the first geometry argument
geom1	the second geometry argument
opCode	the code for the desired overlay operation
pm	the precision model to use

Returns: the result of the overlay operation

◆ overlay() [3/4]

static std::unique_ptr< Geometry > geos::operation::overlayng::OverlayNG::overlay	(	const Geometry *	geom0,
		const Geometry *	geom1,
		int	opCode,
		const PrecisionModel *	pm,
		noding::Noder *	noder
	)

static

Computes an overlay operation on the given geometry operands, using a supplied noding::Noder.

Parameters

geom0	the first geometry argument
geom1	the second geometry argument
opCode	the code for the desired overlay operation
pm	the precision model to use (which may be null if the noder does not use one)
noder	the noder to use

Returns: the result of the overlay operation

◆ overlay() [4/4]

static std::unique_ptr< Geometry > geos::operation::overlayng::OverlayNG::overlay	(	const Geometry *	geom0,
		const Geometry *	geom1,
		int	opCode,
		noding::Noder *	noder
	)

static

Computes an overlay operation on the given geometry operands, using a supplied noding::Noder.

Parameters

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

Returns: the result of the overlay operation

◆ setOptimized()

void geos::operation::overlayng::OverlayNG::setOptimized ( bool p_isOptimized )

inline

Sets whether overlay processing optimizations are enabled. It may be useful to disable optimizations for testing purposes. Default is TRUE (optimization enabled).

Parameters

p_isOptimized whether to optimize processing

Member Data Documentation

◆ STRICT_MODE_DEFAULT

constexpr bool geos::operation::overlayng::OverlayNG::STRICT_MODE_DEFAULT = false

staticconstexpr

The default setting for Strict Mode.

The original JTS overlay semantics used non-strict result semantics, including;

An Intersection result can be mixed-dimension, due to inclusion of intersection components of all dimensions
Results can include lines caused by Area topology collapse

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

OverlayNG.h

Public Member Functions

Static Public Member Functions

Static Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ OverlayNG() [1/3]

◆ OverlayNG() [2/3]

◆ OverlayNG() [3/3]

Member Function Documentation

◆ geomunion() [1/2]

◆ geomunion() [2/2]

◆ getResult()

◆ isResultOfOp()

◆ isResultOfOpPoint()

◆ overlay() [1/4]

◆ overlay() [2/4]

◆ overlay() [3/4]

◆ overlay() [4/4]

◆ setOptimized()

Member Data Documentation

◆ STRICT_MODE_DEFAULT