Tests whether a Geometry is simple. More...

#include <IsSimpleOp.h>

Collaboration diagram for geos::operation::IsSimpleOp:

Public Member Functions
	IsSimpleOp ()
	Creates a simplicity checker using the default SFS Mod-2 Boundary Node Rule. More...

	IsSimpleOp (const geom::Geometry &geom)
	Creates a simplicity checker using the default SFS Mod-2 Boundary Node Rule. More...

	IsSimpleOp (const geom::Geometry &geom, const algorithm::BoundaryNodeRule &boundaryNodeRule)
	Creates a simplicity checker using a given algorithm::BoundaryNodeRule. More...

bool	isSimple ()
	Tests whether the geometry is simple. More...

const geom::Coordinate *	getNonSimpleLocation () const
	Gets a coordinate for the location where the geometry fails to be simple (i.e. where it has a non-boundary self-intersection). More...

bool	isSimple (const geom::LineString *geom)
	Reports whether a geom::LineString is simple. More...

bool	isSimple (const geom::MultiLineString *geom)
	Reports whether a geom::MultiLineString is simple. More...

bool	isSimple (const geom::MultiPoint *mp)
	A MultiPoint is simple iff it has no repeated points. More...

bool	isSimpleLinearGeometry (const geom::Geometry *geom)

Private Member Functions
bool	hasNonEndpointIntersection (geomgraph::GeometryGraph &graph)

bool	hasClosedEndpointIntersection (geomgraph::GeometryGraph &graph)

bool	computeSimple (const geom::Geometry *geom)

bool	isSimplePolygonal (const geom::Geometry *geom)

bool	isSimpleGeometryCollection (const geom::GeometryCollection *col)

void	addEndpoint (std::map< const geom::Coordinate , EndpointInfo , geom::CoordinateLessThen > &endPoints, const geom::Coordinate *p, bool isClosed)

bool	isSimpleMultiPoint (const geom::MultiPoint &mp)

Private Attributes
bool	isClosedEndpointsInInterior

const geom::Geometry *	geom

std::unique_ptr< geom::Coordinate >	nonSimpleLocation

Detailed Description

Tests whether a Geometry is simple.

In general, the SFS specification of simplicity follows the rule:

A Geometry is simple if and only if the only self-intersections are at boundary points.

This definition relies on the definition of boundary points. The SFS uses the Mod-2 rule to determine which points are on the boundary of lineal geometries, but this class supports using other BoundaryNodeRules as well.

Simplicity is defined for each Geometry subclass as follows:

Valid polygonal geometries are simple by definition, so isSimple trivially returns true. (Hint: in order to check if a polygonal geometry has self-intersections, use geom::Geometry::isValid()).
Linear geometries are simple iff they do not self-intersect at points other than boundary points. (Using the Mod-2 rule, this means that closed linestrings cannot be touched at their endpoints, since these are interior points, not boundary points).
Zero-dimensional geometries (points) are simple iff they have no repeated points.
Empty Geometrys are always simple

See also: algorithm::BoundaryNodeRule

Definition at line 96 of file IsSimpleOp.h.

Constructor & Destructor Documentation

geos::operation::IsSimpleOp::IsSimpleOp ( )

Creates a simplicity checker using the default SFS Mod-2 Boundary Node Rule.

Deprecated:: use IsSimpleOp(Geometry)

geos::operation::IsSimpleOp::IsSimpleOp ( const geom::Geometry & geom )

Creates a simplicity checker using the default SFS Mod-2 Boundary Node Rule.

Parameters

geom	The geometry to test. Will store a reference: keep it alive.

geos::operation::IsSimpleOp::IsSimpleOp	(	const geom::Geometry &	geom,
		const algorithm::BoundaryNodeRule &	boundaryNodeRule
	)

Creates a simplicity checker using a given algorithm::BoundaryNodeRule.

Parameters

geom	the geometry to test
boundaryNodeRule	the rule to use.

Member Function Documentation

void geos::operation::IsSimpleOp::addEndpoint	(	std::map< const geom::Coordinate , EndpointInfo , geom::CoordinateLessThen > &	endPoints,
		const geom::Coordinate *	p,
		bool	isClosed
	)

private

Add an endpoint to the map, creating an entry for it if none exists

bool geos::operation::IsSimpleOp::computeSimple ( const geom::Geometry * geom )

private

const geom::Coordinate* geos::operation::IsSimpleOp::getNonSimpleLocation ( ) const

inline

Gets a coordinate for the location where the geometry fails to be simple (i.e. where it has a non-boundary self-intersection).

isSimple must be called before this method is called.

Returns: a coordinate for the location of the non-boundary self-intersection. Ownership retained.; the null coordinate if the geometry is simple

Definition at line 145 of file IsSimpleOp.h.

bool geos::operation::IsSimpleOp::hasClosedEndpointIntersection ( geomgraph::GeometryGraph & graph )

private

Tests that no edge intersection is the endpoint of a closed line. This ensures that closed lines are not touched at their endpoint, which is an interior point according to the Mod-2 rule To check this we compute the degree of each endpoint. The degree of endpoints of closed lines must be exactly 2.

bool geos::operation::IsSimpleOp::hasNonEndpointIntersection ( geomgraph::GeometryGraph & graph )

private

For all edges, check if there are any intersections which are NOT at an endpoint. The Geometry is not simple if there are intersections not at endpoints.

bool geos::operation::IsSimpleOp::isSimple ( )

Tests whether the geometry is simple.

Returns: true if the geometry is simple

bool geos::operation::IsSimpleOp::isSimple ( const geom::LineString * geom )

Reports whether a geom::LineString is simple.

Parameters

geom	the lineal geometry to test

Returns: true if the geometry is simple

Deprecated:: use isSimple()

bool geos::operation::IsSimpleOp::isSimple ( const geom::MultiLineString * geom )

Reports whether a geom::MultiLineString is simple.

Parameters

geom	the lineal geometry to test

Returns: true if the geometry is simple

Deprecated:: use isSimple()

bool geos::operation::IsSimpleOp::isSimple ( const geom::MultiPoint * mp )

A MultiPoint is simple iff it has no repeated points.

Deprecated:: use isSimple()

bool geos::operation::IsSimpleOp::isSimpleGeometryCollection ( const geom::GeometryCollection * col )

private

bool geos::operation::IsSimpleOp::isSimpleLinearGeometry ( const geom::Geometry * geom )

bool geos::operation::IsSimpleOp::isSimpleMultiPoint ( const geom::MultiPoint & mp )

private

bool geos::operation::IsSimpleOp::isSimplePolygonal ( const geom::Geometry * geom )

private

Member Data Documentation

const geom::Geometry* geos::operation::IsSimpleOp::geom

private

Definition at line 214 of file IsSimpleOp.h.

bool geos::operation::IsSimpleOp::isClosedEndpointsInInterior

private

Definition at line 210 of file IsSimpleOp.h.

std::unique_ptr<geom::Coordinate> geos::operation::IsSimpleOp::nonSimpleLocation

private

Definition at line 216 of file IsSimpleOp.h.

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

IsSimpleOp.h

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation