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

#include <OverlayOp.h>

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

Collaboration 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...

	~OverlayOp () override

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)

virtual	~GeometryGraphOperation ()

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)

Private Member Functions
void	computeOverlay (OpCode opCode)

void	insertUniqueEdges (std::vector< geomgraph::Edge * > edges, const geom::Envelope env=nullptr)

void	computeLabelsFromDepths ()
	Update the labels for edges according to their depths. More...

void	replaceCollapsedEdges ()
	If edges which have undergone dimensional collapse are found, replace them with a new edge which is a L edge. More...

void	copyPoints (int argIndex, const geom::Envelope *env=nullptr)
	Copy all nodes from an arg geometry into this graph. More...

void	computeLabelling ()
	Compute initial labelling for all DirectedEdges at each node. More...

void	mergeSymLabels ()

void	updateNodeLabelling ()

void	labelIncompleteNodes ()

void	labelIncompleteNode (geomgraph::Node *n, int targetIndex)
	Label an isolated node with its relationship to the target geometry. More...

void	findResultAreaEdges (OpCode opCode)
	Find all edges whose label indicates that they are in the result area(s), according to the operation being performed. More...

void	cancelDuplicateResultEdges ()

bool	isCovered (const geom::Coordinate &coord, std::vector< geom::Geometry * > *geomList)

bool	isCovered (const geom::Coordinate &coord, std::vector< geom::Polygon * > *geomList)

bool	isCovered (const geom::Coordinate &coord, std::vector< geom::LineString * > *geomList)

geom::Geometry *	computeGeometry (std::vector< geom::Point * > nResultPointList, std::vector< geom::LineString > nResultLineList, std::vector< geom::Polygon > *nResultPolyList, OverlayOp::OpCode opCode)

int	mergeZ (geomgraph::Node n, const geom::Polygon poly) const
	Merge Z values of node with those of the segment or vertex in the given Polygon it is on. More...

int	mergeZ (geomgraph::Node n, const geom::LineString line) const

double	getAverageZ (int targetIndex)

void	checkObviouslyWrongResult (OpCode opCode)

Static Private Member Functions
static geom::Dimension::DimensionType	resultDimension (OverlayOp::OpCode overlayOpCode, const geom::Geometry g0, const geom::Geometry g1)

static double	getAverageZ (const geom::Polygon *poly)

Private Attributes
algorithm::PointLocator	ptLocator

const geom::GeometryFactory *	geomFact

geom::Geometry *	resultGeom

geomgraph::PlanarGraph	graph

geomgraph::EdgeList	edgeList

std::vector< geom::Polygon * > *	resultPolyList

std::vector< geom::LineString * > *	resultLineList

std::vector< geom::Point * > *	resultPointList

std::vector< geomgraph::Edge * >	dupEdges
	Caches for memory management. More...

double	avgz [2]

bool	avgzcomputed [2]

ElevationMatrix *	elevationMatrix

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. More...

Detailed Description

Computes the geometric overlay of two Geometry.

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

Definition at line 70 of file OverlayOp.h.

Member Enumeration Documentation

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.

Definition at line 79 of file OverlayOp.h.

Constructor & Destructor Documentation

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.

geos::operation::overlay::OverlayOp::~OverlayOp ( )

override

Member Function Documentation

void geos::operation::overlay::OverlayOp::cancelDuplicateResultEdges ( )

private

If both a dirEdge and its sym are marked as being in the result, cancel them out.

void geos::operation::overlay::OverlayOp::checkObviouslyWrongResult ( OpCode opCode )

private

Throw TopologyException if an obviously wrong result has been computed.

geom::Geometry* geos::operation::overlay::OverlayOp::computeGeometry	(	std::vector< geom::Point * > *	nResultPointList,
		std::vector< geom::LineString * > *	nResultLineList,
		std::vector< geom::Polygon * > *	nResultPolyList,
		OverlayOp::OpCode	opCode
	)

private

Build a Geometry containing all Geometries in the given vectors. Takes element's ownership, vector control is left to caller.

void geos::operation::overlay::OverlayOp::computeLabelling ( )

private

Compute initial labelling for all DirectedEdges at each node.

In this step, DirectedEdges will acquire a complete labelling (i.e. one with labels for both Geometries) only if they are incident on a node which has edges for both Geometries

void geos::operation::overlay::OverlayOp::computeLabelsFromDepths ( )

private

Update the labels for edges according to their depths.

For each edge, the depths are first normalized. Then, if the depths for the edge are equal, this edge must have collapsed into a line edge. If the depths are not equal, update the label with the locations corresponding to the depths (i.e. a depth of 0 corresponds to a Location of EXTERIOR, a depth of 1 corresponds to INTERIOR)

void geos::operation::overlay::OverlayOp::computeOverlay ( OpCode opCode )

private

void geos::operation::overlay::OverlayOp::copyPoints	(	int	argIndex,
		const geom::Envelope *	env = `nullptr`
	)

private

Copy all nodes from an arg geometry into this graph.

The node label in the arg geometry overrides any previously computed label for that argIndex. (E.g. a node may be an intersection node with a previously computed label of BOUNDARY, but in the original arg Geometry it is actually in the interior due to the Boundary Determination Rule)

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

void geos::operation::overlay::OverlayOp::findResultAreaEdges ( OpCode opCode )

private

Find all edges whose label indicates that they are in the result area(s), according to the operation being performed.

Since we want polygon shells to be oriented CW, choose dirEdges with the interior of the result on the RHS. Mark them as being in the result. Interior Area edges are the result of dimensional collapses. They do not form part of the result area boundary.

double geos::operation::overlay::OverlayOp::getAverageZ ( int targetIndex )

private

static double geos::operation::overlay::OverlayOp::getAverageZ ( const geom::Polygon * poly )

staticprivate

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

inline

Gets the graph constructed to compute the overlay.

Returns: the overlay graph

Definition at line 151 of file OverlayOp.h.

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

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.

void geos::operation::overlay::OverlayOp::insertUniqueEdges	(	std::vector< geomgraph::Edge * > *	edges,
		const geom::Envelope *	env = `nullptr`
	)

private

bool geos::operation::overlay::OverlayOp::isCovered	(	const geom::Coordinate &	coord,
		std::vector< geom::Geometry * > *	geomList
	)

private

Returns: true if the coord is located in the interior or boundary of a geometry in the list.

bool geos::operation::overlay::OverlayOp::isCovered	(	const geom::Coordinate &	coord,
		std::vector< geom::Polygon * > *	geomList
	)

private

Returns: true if the coord is located in the interior or boundary of a geometry in the list.

bool geos::operation::overlay::OverlayOp::isCovered	(	const geom::Coordinate &	coord,
		std::vector< geom::LineString * > *	geomList
	)

private

Returns: true if the coord is located in the interior or boundary of a geometry in the list.

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

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

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

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

void geos::operation::overlay::OverlayOp::labelIncompleteNode	(	geomgraph::Node *	n,
		int	targetIndex
	)

private

Label an isolated node with its relationship to the target geometry.

void geos::operation::overlay::OverlayOp::labelIncompleteNodes ( )

private

Incomplete nodes are nodes whose labels are incomplete.

(e.g. the location for one Geometry is NULL). These are either isolated nodes, or nodes which have edges from only a single Geometry incident on them.

Isolated nodes are found because nodes in one graph which don't intersect nodes in the other are not completely labelled by the initial process of adding nodes to the nodeList. To complete the labelling we need to check for nodes that lie in the interior of edges, and in the interior of areas.

When each node labelling is completed, the labelling of the incident edges is updated, to complete their labelling as well.

void geos::operation::overlay::OverlayOp::mergeSymLabels ( )

private

For nodes which have edges from only one Geometry incident on them, the previous step will have left their dirEdges with no labelling for the other Geometry. However, the sym dirEdge may have a labelling for the other Geometry, so merge the two labels.

int geos::operation::overlay::OverlayOp::mergeZ	(	geomgraph::Node *	n,
		const geom::Polygon *	poly
	)		const

private

Merge Z values of node with those of the segment or vertex in the given Polygon it is on.

int geos::operation::overlay::OverlayOp::mergeZ	(	geomgraph::Node *	n,
		const geom::LineString *	line
	)		const

private

Merge Z values of node with those of the segment or vertex in the given LineString it is on.

Returns: 1 if an intersection is found, 0 otherwise.

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

void geos::operation::overlay::OverlayOp::replaceCollapsedEdges ( )

private

If edges which have undergone dimensional collapse are found, replace them with a new edge which is a L edge.

static geom::Dimension::DimensionType geos::operation::overlay::OverlayOp::resultDimension	(	OverlayOp::OpCode	overlayOpCode,
		const geom::Geometry *	g0,
		const geom::Geometry *	g1
	)

staticprivate

For empty result, what is the correct geometry type to apply to the empty?

void geos::operation::overlay::OverlayOp::updateNodeLabelling ( )

private

Member Data Documentation

double geos::operation::overlay::OverlayOp::avgz[2]

private

Average Z of input geometries

Definition at line 389 of file OverlayOp.h.

bool geos::operation::overlay::OverlayOp::avgzcomputed[2]

private

Definition at line 390 of file OverlayOp.h.

std::vector<geomgraph::Edge*> geos::operation::overlay::OverlayOp::dupEdges

private

Caches for memory management.

Definition at line 371 of file OverlayOp.h.

geomgraph::EdgeList geos::operation::overlay::OverlayOp::edgeList

private

Definition at line 217 of file OverlayOp.h.

ElevationMatrix* geos::operation::overlay::OverlayOp::elevationMatrix

private

Definition at line 395 of file OverlayOp.h.

const geom::GeometryFactory* geos::operation::overlay::OverlayOp::geomFact

private

Definition at line 211 of file OverlayOp.h.

geomgraph::PlanarGraph geos::operation::overlay::OverlayOp::graph

private

Definition at line 215 of file OverlayOp.h.

algorithm::PointLocator geos::operation::overlay::OverlayOp::ptLocator

private

Definition at line 209 of file OverlayOp.h.

geom::Geometry* geos::operation::overlay::OverlayOp::resultGeom

private

Definition at line 213 of file OverlayOp.h.

std::vector<geom::LineString*>* geos::operation::overlay::OverlayOp::resultLineList

private

Definition at line 221 of file OverlayOp.h.

std::vector<geom::Point*>* geos::operation::overlay::OverlayOp::resultPointList

private

Definition at line 223 of file OverlayOp.h.

std::vector<geom::Polygon*>* geos::operation::overlay::OverlayOp::resultPolyList

private

Definition at line 219 of file OverlayOp.h.

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

Private Member Functions

Static Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation