geos::noding::BoundaryChainNoder Class Reference

#include <BoundaryChainNoder.h>

Inheritance diagram for geos::noding::BoundaryChainNoder:

Public Types
using	SegmentSet = std::unordered_set< Segment, Segment::HashCode >

Public Member Functions
std::vector< SegmentString * > *	getNodedSubstrings () const override
	Returns a collection of fully noded SegmentStrings. The SegmentStrings have the same context as their parent.
void	computeNodes (std::vector< SegmentString * > *inputSegStrings) override
	Computes the noding for a collection of SegmentStrings.

Detailed Description

A noder which extracts chains of boundary segments as SegmentStrings from a polygonal coverage. Boundary segments are those which are not duplicated in the input polygonal coverage. Extracting chains of segments minimize the number of segment strings created, which produces a more efficient topological graph structure.

This enables fast overlay of polygonal coverages in CoverageUnion. Using this noder is faster than SegmentExtractingNoder and BoundarySegmentNoder.

No precision reduction is carried out. If that is required, another noder must be used (such as a snap-rounding noder), or the input must be precision-reduced beforehand.

Author

Martin Davis

Member Function Documentation

computeNodes()

void geos::noding::BoundaryChainNoder::computeNodes ( std::vector< SegmentString * > *  segStrings )

overridevirtual

Computes the noding for a collection of SegmentStrings.

Some Noders may add all these nodes to the input SegmentStrings; others may only add some or none at all.

Parameters

segStrings

a collection of SegmentStrings to node The caller remains responsible for releasing the memory associated with the container and its elements.

Implements geos::noding::Noder.

getNodedSubstrings()

std::vector< SegmentString * > * geos::noding::BoundaryChainNoder::getNodedSubstrings ( ) const

overridevirtual

Returns a collection of fully noded SegmentStrings. The SegmentStrings have the same context as their parent.

Returns

a newly allocated std::vector of newly allocated SegmentStrings (copies of input, if needs be). Caller is responsible to delete container and elements.

Implements geos::noding::Noder.

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

• BoundaryChainNoder.h