#include <LineBuilder.h>

Collaboration diagram for geos::operation::overlayng::LineBuilder:

Public Member Functions
	LineBuilder (const InputGeometry inputGeom, OverlayGraph p_graph, bool p_hasResultArea, int p_opCode, const geom::GeometryFactory *geomFact)

	LineBuilder (const LineBuilder &)=delete

LineBuilder &	operator= (const LineBuilder &)=delete

std::vector< std::unique_ptr< geom::LineString > >	getLines ()

void	setStrictMode (bool p_isStrictResultMode)

Private Member Functions
void	markResultLines ()

bool	isResultLine (const OverlayLabel *lbl) const

geom::Location	effectiveLocation (const OverlayLabel *lbl, int geomIndex) const

void	addResultLines ()

void	addResultLinesMerged ()

std::unique_ptr< geom::LineString >	toLine (OverlayEdge *edge)

void	addResultLinesForNodes ()

void	addResultLinesRings ()

std::unique_ptr< geom::LineString >	buildLine (OverlayEdge *node)

OverlayEdge *	nextLineEdgeUnvisited (OverlayEdge *node) const

int	degreeOfLines (OverlayEdge *node) const

Private Attributes
OverlayGraph *	graph

int	opCode

const geom::GeometryFactory *	geometryFactory

bool	hasResultArea

int	inputAreaIndex

std::vector< std::unique_ptr< geom::LineString > >	lines

bool	isAllowMixedResult = ! OverlayNG::STRICT_MODE_DEFAULT

bool	isAllowCollapseLines = ! OverlayNG::STRICT_MODE_DEFAULT

Detailed Description

Finds and builds overlay result lines from the overlay graph. Output linework has the following semantics:

Linework is fully noded
Lines are as long as possible between nodes

Various strategies are possible for how to merge graph edges into lines. This implementation uses the approach of having output lines run contiguously from node to node. For rings a node point is chosen arbitrarily.

Another possible strategy would be to preserve input linework as far as possible (i.e. any sections of input lines which are not coincident with other linework would be preserved).

It would also be possible to output LinearRings, if the input is a LinearRing and is unchanged. This will require additional info from the input linework.

Author: Martin Davis

Definition at line 70 of file g/LineBuilder.h.

Constructor & Destructor Documentation

geos::operation::overlayng::LineBuilder::LineBuilder	(	const InputGeometry *	inputGeom,
		OverlayGraph *	p_graph,
		bool	p_hasResultArea,
		int	p_opCode,
		const geom::GeometryFactory *	geomFact
	)

inline

Definition at line 163 of file g/LineBuilder.h.

geos::operation::overlayng::LineBuilder::LineBuilder ( const LineBuilder & )

delete

Member Function Documentation

void geos::operation::overlayng::LineBuilder::addResultLines ( )

private

void geos::operation::overlayng::LineBuilder::addResultLinesForNodes ( )

private

void geos::operation::overlayng::LineBuilder::addResultLinesMerged ( )

private

void geos::operation::overlayng::LineBuilder::addResultLinesRings ( )

private

Adds lines which form rings (i.e. have only degree-2 vertices).

std::unique_ptr<geom::LineString> geos::operation::overlayng::LineBuilder::buildLine ( OverlayEdge * node )

private

Traverses edges from edgeStart which lie in a single line (have degree = 2).

The direction of the linework is preserved as far as possible. Specifically, the direction of the line is determined by the start edge direction. This implies that if all edges are reversed, the created line will be reversed to match. (Other more complex strategies would be possible. E.g. using the direction of the majority of segments, or preferring the direction of the A edges.)

int geos::operation::overlayng::LineBuilder::degreeOfLines ( OverlayEdge * node ) const

private

Computes the degree of the line edges incident on a node

geom::Location geos::operation::overlayng::LineBuilder::effectiveLocation	(	const OverlayLabel *	lbl,
		int	geomIndex
	)		const

private

Determines the effective location for a line, for the purpose of overlay operation evaluation. Line edges and Collapses are reported as INTERIOR so they may be included in the result if warranted by the effect of the operation on the two edges. (For instance, the intersection of line edge and a collapsed boundary is included in the result).

std::vector<std::unique_ptr<geom::LineString> > geos::operation::overlayng::LineBuilder::getLines ( )

bool geos::operation::overlayng::LineBuilder::isResultLine ( const OverlayLabel * lbl ) const

private

Checks if the topology indicated by an edge label determines that this edge should be part of a result line.

Note that the logic here relies on the semantic that for intersection lines are only returned if there is no result area components.

void geos::operation::overlayng::LineBuilder::markResultLines ( )

private

OverlayEdge* geos::operation::overlayng::LineBuilder::nextLineEdgeUnvisited ( OverlayEdge * node ) const

private

LineBuilder& geos::operation::overlayng::LineBuilder::operator= ( const LineBuilder & )

delete

void geos::operation::overlayng::LineBuilder::setStrictMode ( bool p_isStrictResultMode )

inline

Definition at line 178 of file g/LineBuilder.h.

std::unique_ptr<geom::LineString> geos::operation::overlayng::LineBuilder::toLine ( OverlayEdge * edge )

private

Member Data Documentation

const geom::GeometryFactory* geos::operation::overlayng::LineBuilder::geometryFactory

private

Definition at line 77 of file g/LineBuilder.h.

OverlayGraph* geos::operation::overlayng::LineBuilder::graph

private

Definition at line 75 of file g/LineBuilder.h.

bool geos::operation::overlayng::LineBuilder::hasResultArea

private

Definition at line 78 of file g/LineBuilder.h.

int geos::operation::overlayng::LineBuilder::inputAreaIndex

private

Definition at line 79 of file g/LineBuilder.h.

bool geos::operation::overlayng::LineBuilder::isAllowCollapseLines = ! OverlayNG::STRICT_MODE_DEFAULT

private

Allow lines created by area topology collapses to appear in the result. True provides the original JTS semantics.

Definition at line 95 of file g/LineBuilder.h.

bool geos::operation::overlayng::LineBuilder::isAllowMixedResult = ! OverlayNG::STRICT_MODE_DEFAULT

private

Indicates whether intersections are allowed to produce heterogeneous results including proper boundary touches. This does not control inclusion of touches along collapses. True provides the original JTS semantics.

Definition at line 88 of file g/LineBuilder.h.

std::vector<std::unique_ptr<geom::LineString> > geos::operation::overlayng::LineBuilder::lines

private

Definition at line 80 of file g/LineBuilder.h.

int geos::operation::overlayng::LineBuilder::opCode

private

Definition at line 76 of file g/LineBuilder.h.

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

g/LineBuilder.h

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation