#include <OverlayNGRobust.h>

Classes
class	SRUnionStrategy

Static Public Member Functions
static std::unique_ptr< Geometry >	Intersection (const Geometry g0, const Geometry g1)

static std::unique_ptr< Geometry >	Union (const Geometry g0, const Geometry g1)

static std::unique_ptr< Geometry >	Difference (const Geometry g0, const Geometry g1)

static std::unique_ptr< Geometry >	SymDifference (const Geometry g0, const Geometry g1)

static std::unique_ptr< Geometry >	Union (const Geometry *a)

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

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

static double	snapTolerance (const Geometry geom0, const Geometry geom1)

Static Private Member Functions
static std::unique_ptr< Geometry >	overlaySnapping (const Geometry geom0, const Geometry geom1, int opCode, double snapTol)

static std::unique_ptr< Geometry >	overlaySnapBoth (const Geometry geom0, const Geometry geom1, int opCode, double snapTol)

static std::unique_ptr< Geometry >	overlaySnapTol (const Geometry geom0, const Geometry geom1, int opCode, double snapTol)

static double	snapTolerance (const Geometry *geom)

static double	ordinateMagnitude (const Geometry *geom)

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

static std::unique_ptr< Geometry >	snapSelf (const Geometry *geom, double snapTol)

Static Private Attributes
static constexpr int	NUM_SNAP_TRIES = 5

static constexpr double	SNAP_TOL_FACTOR = 1e12

Detailed Description

Performs an overlay operation, increasing robustness by using a series of increasingly aggressive (and slower) noding strategies.

The noding strategies used are:

A simple, fast noder using FLOATING precision.
A noding::snap::SnappingNoder using an automatically-determined snap tolerance
First snapping each geometry to itself, and then overlaying them using a SnappingNoder.
The above two strategies are repeated with increasing snap tolerance, up to a limit.

If the above heuristics still fail to compute a valid overlay, the original util::TopologyException is thrown.

This algorithm relies on each overlay operation execution throwing a util::TopologyException if it is unable to compute the overlay correctly. Generally this occurs because the noding phase does not produce a valid noding. This requires the use of a noding::ValidatingNoder in order to check the results of using a floating noder.

Author: Martin Davis

Definition at line 64 of file OverlayNGRobust.h.

Member Function Documentation

static std::unique_ptr<Geometry> geos::operation::overlayng::OverlayNGRobust::Difference	(	const Geometry *	g0,
		const Geometry *	g1
	)

static

static std::unique_ptr<Geometry> geos::operation::overlayng::OverlayNGRobust::Intersection	(	const Geometry *	g0,
		const Geometry *	g1
	)

static

static double geos::operation::overlayng::OverlayNGRobust::ordinateMagnitude ( const Geometry * geom )

staticprivate

Computes the largest magnitude of the ordinates of a geometry, based on the geometry envelope.

Parameters

geom	a geometry

Returns: the magnitude of the largest ordinate

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

static

static std::unique_ptr<Geometry> geos::operation::overlayng::OverlayNGRobust::overlaySnapBoth	(	const Geometry *	geom0,
		const Geometry *	geom1,
		int	opCode,
		double	snapTol
	)

staticprivate

static std::unique_ptr<Geometry> geos::operation::overlayng::OverlayNGRobust::overlaySnapping	(	const Geometry *	geom0,
		const Geometry *	geom1,
		int	opCode,
		double	snapTol
	)

staticprivate

static std::unique_ptr<Geometry> geos::operation::overlayng::OverlayNGRobust::overlaySnapTol	(	const Geometry *	geom0,
		const Geometry *	geom1,
		int	opCode,
		double	snapTol
	)

staticprivate

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

static

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

staticprivate

Overlay using Snap-Rounding with an automatically-determined scale factor.

NOTE: currently this strategy is not used, since all known test cases work using one of the Snapping strategies.

static std::unique_ptr<Geometry> geos::operation::overlayng::OverlayNGRobust::snapSelf	(	const Geometry *	geom,
		double	snapTol
	)

staticprivate

Self-snaps a geometry by running a union operation with it as the only input. This helps to remove narrow spike/gore artifacts to simplify the geometry, which improves robustness. Collapsed artifacts are removed from the result to allow using it in further overlay operations.

Parameters

geom	geometry to self-snap
snapTol	snap tolerance

Returns: the snapped geometry (homogeneous)

static double geos::operation::overlayng::OverlayNGRobust::snapTolerance ( const Geometry * geom )

staticprivate

static double geos::operation::overlayng::OverlayNGRobust::snapTolerance	(	const Geometry *	geom0,
		const Geometry *	geom1
	)

static

Computes a heuristic snap tolerance distance for overlaying a pair of geometries using a noding::snap::SnappingNoder.

static std::unique_ptr<Geometry> geos::operation::overlayng::OverlayNGRobust::SymDifference	(	const Geometry *	g0,
		const Geometry *	g1
	)

static

static std::unique_ptr<Geometry> geos::operation::overlayng::OverlayNGRobust::Union	(	const Geometry *	g0,
		const Geometry *	g1
	)

static

static std::unique_ptr<Geometry> geos::operation::overlayng::OverlayNGRobust::Union ( const Geometry * a )

static

Member Data Documentation

constexpr int geos::operation::overlayng::OverlayNGRobust::NUM_SNAP_TRIES = 5

staticprivate

Definition at line 70 of file OverlayNGRobust.h.

constexpr double geos::operation::overlayng::OverlayNGRobust::SNAP_TOL_FACTOR = 1e12

staticprivate

A factor for a snapping tolerance distance which should allow noding to be computed robustly.

Definition at line 75 of file OverlayNGRobust.h.

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

OverlayNGRobust.h

Classes

Static Public Member Functions

Static Private Member Functions

Static Private Attributes

Detailed Description

Member Function Documentation

Member Data Documentation