geos::operation::polygonize::PolygonizeGraph Class Reference

Represents a planar graph of edges that can be used to compute a polygonization, and implements the algorithms to compute the EdgeRings formed by the graph. More...

#include <PolygonizeGraph.h>

Inheritance diagram for geos::operation::polygonize::PolygonizeGraph:

Public Member Functions
	PolygonizeGraph (const geom::GeometryFactory *newFactory)
	Create a new polygonization graph.
	~PolygonizeGraph () override
	Destroy a polygonization graph.
void	addEdge (const geom::LineString *line)
	Add a LineString forming an edge of the polygon graph.
void	getEdgeRings (std::vector< EdgeRing * > &edgeRingList)
	Computes the EdgeRings formed by the edges in this graph.
void	deleteCutEdges (std::vector< const geom::LineString * > &cutLines)
	Finds and removes all cut edges from the graph.
void	deleteDangles (std::vector< const geom::LineString * > &dangleLines)
	Marks all edges from the graph which are "dangles".
Public Member Functions inherited from geos::planargraph::PlanarGraph
	PlanarGraph ()
	Constructs a PlanarGraph without any Edges, DirectedEdges, or Nodes.
Node *	findNode (const geom::Coordinate &pt)
	Returns the Node at the given location, or null if no Node was there.
NodeMap::container::iterator	nodeIterator ()
	Returns an Iterator over the Nodes in this PlanarGraph.
NodeMap::container::iterator	nodeBegin ()
NodeMap::container::const_iterator	nodeBegin () const
NodeMap::container::iterator	nodeEnd ()
NodeMap::container::const_iterator	nodeEnd () const
void	getNodes (std::vector< Node * > &nodes)
	Returns the Nodes in this PlanarGraph.
std::vector< DirectedEdge * >::iterator	dirEdgeIterator ()
	Returns an Iterator over the DirectedEdges in this PlanarGraph, in the order in which they were added.
std::vector< DirectedEdge * >::iterator	dirEdgeBegin ()
std::vector< DirectedEdge * >::iterator	dirEdgeEnd ()
std::vector< Edge * >::iterator	edgeIterator ()
	Alias for edgeBegin()
std::vector< Edge * >::iterator	edgeBegin ()
	Returns an iterator to first Edge in this graph.
std::vector< Edge * >::iterator	edgeEnd ()
	Returns an iterator to one-past last Edge in this graph.
std::vector< Edge * > *	getEdges ()
void	remove (Edge *edge)
	Removes an Edge and its associated DirectedEdges from their from-Nodes and from this PlanarGraph.
void	remove (DirectedEdge *de)
	Removes DirectedEdge from its from-Node and from this PlanarGraph.
void	remove (Node *node)
	Removes a node from the graph, along with any associated DirectedEdges and Edges.
std::vector< Node * > *	findNodesOfDegree (std::size_t degree)
	Returns all Nodes with the given number of Edges around it. The return value is a newly allocated vector of existing nodes.
void	findNodesOfDegree (std::size_t degree, std::vector< Node * > &to)
	Get all Nodes with the given number of Edges around it.

Static Public Member Functions
static void	deleteAllEdges (planargraph::Node *node)
	Deletes all edges at a node.

Additional Inherited Members
Public Types inherited from geos::planargraph::PlanarGraph
typedef std::vector< Edge * >	EdgeContainer
typedef EdgeContainer::iterator	EdgeIterator
Protected Member Functions inherited from geos::planargraph::PlanarGraph
void	add (Node *node)
	Adds a node to the std::map, replacing any that is already at that location.
void	add (Edge *edge)
	Adds the Edge and its DirectedEdges with this PlanarGraph.
void	add (DirectedEdge *dirEdge)
	Adds the Edge to this PlanarGraph.
Protected Attributes inherited from geos::planargraph::PlanarGraph
std::vector< Edge * >	edges
std::vector< DirectedEdge * >	dirEdges
NodeMap	nodeMap

Detailed Description

Represents a planar graph of edges that can be used to compute a polygonization, and implements the algorithms to compute the EdgeRings formed by the graph.

The marked flag on DirectedEdge is used to indicate that a directed edge has be logically deleted from the graph.

Member Function Documentation

addEdge()

void geos::operation::polygonize::PolygonizeGraph::addEdge

(

const geom::LineString *

line

)

Add a LineString forming an edge of the polygon graph.

Parameters

line	the line to add

deleteCutEdges()

void geos::operation::polygonize::PolygonizeGraph::deleteCutEdges

(

std::vector< const geom::LineString * > &

cutLines

)

Finds and removes all cut edges from the graph.

Parameters

cutLines

: the list of the LineString forming the removed cut edges will be pushed here.

TODO: document ownership of the returned LineStrings

deleteDangles()

void geos::operation::polygonize::PolygonizeGraph::deleteDangles

(

std::vector< const geom::LineString * > &

dangleLines

)

Marks all edges from the graph which are "dangles".

Dangles are which are incident on a node with degree 1. This process is recursive, since removing a dangling edge may result in another edge becoming a dangle. In order to handle large recursion depths efficiently, an explicit recursion stack is used

Parameters

dangleLines

: the LineStrings that formed dangles will be push_back'ed here

getEdgeRings()

void geos::operation::polygonize::PolygonizeGraph::getEdgeRings

(

std::vector< EdgeRing * > &

edgeRingList

)

Computes the EdgeRings formed by the edges in this graph.

Parameters

edgeRingList

: the EdgeRing found by the polygonization process will be pushed here.

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

• PolygonizeGraph.h