Class PlanarGraph

The computation of the IntersectionMatrix relies on the use of a structure called a "topology graph". The topology graph contains nodes and edges corresponding to the nodes and line segments of a Geometry. Each node and edge in the graph is labeled with its topological location relative to the source point. Note that there is no requirement that points of self-intersection be a vertex. Thus to obtain a correct topology graph, Geometrys must be self-noded before constructing their graphs. Two fundamental operations are supported by topology graphs: Computing the intersections between all the edges and nodes of a single graph Computing the intersections between the edges and nodes of two different graphs

Inheritance

Object

PlanarGraph

GeometryGraph

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: NetTopologySuite.GeometriesGraph

Assembly: NetTopologySuite.dll

Syntax

public class PlanarGraph

Constructors

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PlanarGraph()

Creates an instance of this class using the default NodeFactory.

Declaration

public PlanarGraph()

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PlanarGraph(NodeFactory)

Creates an instance of this class using the provided NodeFactory

Declaration

public PlanarGraph(NodeFactory nodeFact)

Parameters

Type	Name	Description
NodeFactory	nodeFact	A factory to create `Node`s

Fields

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edgeEndList

Declaration

protected IList<EdgeEnd> edgeEndList

Field Value

Type	Description
IList<EdgeEnd>

Properties

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EdgeEnds

Declaration

public IList<EdgeEnd> EdgeEnds { get; }

Property Value

Type	Description
IList<EdgeEnd>

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Edges

Declaration

protected IList<Edge> Edges { get; }

Property Value

Type	Description
IList<Edge>

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NodeMap

Declaration

protected NodeMap NodeMap { get; }

Property Value

Type	Description
NodeMap

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Nodes

Declaration

public IList<Node> Nodes { get; }

Property Value

Type	Description
IList<Node>

Methods

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Add(EdgeEnd)

Declaration

public void Add(EdgeEnd e)

Parameters

Type	Name	Description
EdgeEnd	e

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AddEdges(IList<Edge>)

Add a set of edges to the graph. For each edge two DirectedEdges will be created. DirectedEdges are NOT linked by this method.

Declaration

public void AddEdges(IList<Edge> edgesToAdd)

Parameters

Type	Name	Description
IList<Edge>	edgesToAdd	A set of `Edge`s to add.

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AddNode(Coordinate)

Declaration

public Node AddNode(Coordinate coord)

Parameters

Type	Name	Description
Coordinate	coord

Returns

Type	Description
Node

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AddNode(Node)

Declaration

public Node AddNode(Node node)

Parameters

Type	Name	Description
Node	node

Returns

Type	Description
Node

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Find(Coordinate)

Searches for a Node at Coordinate position coord

Declaration

public Node Find(Coordinate coord)

Parameters

Type	Name	Description
Coordinate	coord	A `Coordinate` position

Returns

Type	Description
Node	The node if found; `null` otherwise

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FindEdge(Coordinate, Coordinate)

Returns the edge whose first two coordinates are p0 and p1.

Declaration

public Edge FindEdge(Coordinate p0, Coordinate p1)

Parameters

Type	Name	Description
Coordinate	p0	The 1st `Coordinate`
Coordinate	p1	The 2nd `Coordinate`

Returns

Type	Description
Edge	The edge, if found `null` if the edge was not found.

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FindEdgeEnd(Edge)

Returns the EdgeEnd which has edge e as its base edge (MD 18 Feb 2002 - this should return a pair of edges).

Declaration

public EdgeEnd FindEdgeEnd(Edge e)

Parameters

Type	Name	Description
Edge	e	An `Edge`

Returns

Type	Description
EdgeEnd	The edge, if found `null` if the edge was not found.

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FindEdgeInSameDirection(Coordinate, Coordinate)

Returns the edge which starts at p0 and whose first segment is parallel to p1.

Declaration

public Edge FindEdgeInSameDirection(Coordinate p0, Coordinate p1)

Parameters

Type	Name	Description
Coordinate	p0	Starting `Coordinate`
Coordinate	p1	`Coordinate` used to establish direction

Returns

Type	Description
Edge	The matching edge, if found `null` if the edge was not found.

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GetEdgeEnumerator()

Declaration

public IEnumerator<Edge> GetEdgeEnumerator()

Returns

Type	Description
IEnumerator<Edge>

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GetNodeEnumerator()

Declaration

public IEnumerator<Node> GetNodeEnumerator()

Returns

Type	Description
IEnumerator<Node>

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InsertEdge(Edge)

Declaration

protected void InsertEdge(Edge e)

Parameters

Type	Name	Description
Edge	e

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IsBoundaryNode(Int32, Coordinate)

Declaration

public bool IsBoundaryNode(int geomIndex, Coordinate coord)

Parameters

Type	Name	Description
Int32	geomIndex
Coordinate	coord

Returns

Type	Description
Boolean

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LinkAllDirectedEdges()

Link the DirectedEdges at the nodes of the graph. This allows clients to link only a subset of nodes in the graph, for efficiency (because they know that only a subset is of interest).

Declaration

public void LinkAllDirectedEdges()

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LinkResultDirectedEdges()

Link the DirectedEdges at the nodes of the graph. This allows clients to link only a subset of nodes in the graph, for efficiency (because they know that only a subset is of interest).

Declaration

public void LinkResultDirectedEdges()

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LinkResultDirectedEdges(IList<Node>)

For nodes in the Collection, link the DirectedEdges at the node that are in the result. This allows clients to link only a subset of nodes in the graph, for efficiency (because they know that only a subset is of interest).

Declaration

public static void LinkResultDirectedEdges(IList<Node> nodes)

Parameters

Type	Name	Description
IList<Node>	nodes	A collection of `Node`s

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WriteEdges(StreamWriter)

Declaration

public void WriteEdges(StreamWriter outstream)

Parameters

Type	Name	Description
StreamWriter	outstream