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

PlanarGraph()

Creates an instance of this class using the default NodeFactory.

Declaration

public PlanarGraph()

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 Nodes

Fields

edgeEndList

Declaration

protected IList<EdgeEnd> edgeEndList

Field Value

Type	Description
IList<EdgeEnd>

Properties

EdgeEnds

Declaration

public IList<EdgeEnd> EdgeEnds { get; }

Property Value

Type	Description
IList<EdgeEnd>

Edges

Declaration

protected IList<Edge> Edges { get; }

Property Value

Type	Description
IList<Edge>

NodeMap

Declaration

protected NodeMap NodeMap { get; }

Property Value

Type	Description
NodeMap

Nodes

Declaration

public IList<Node> Nodes { get; }

Property Value

Type	Description
IList<Node>

Methods

Add(EdgeEnd)

Declaration

public void Add(EdgeEnd e)

Parameters

Type	Name	Description
EdgeEnd	e

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 Edges to add.

AddNode(Coordinate)

Declaration

public Node AddNode(Coordinate coord)

Parameters

Type	Name	Description
Coordinate	coord

Returns

Type	Description
Node

AddNode(Node)

Declaration

public Node AddNode(Node node)

Parameters

Type	Name	Description
Node	node

Returns

Type	Description
Node

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

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.

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.

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.

GetEdgeEnumerator()

Declaration

public IEnumerator<Edge> GetEdgeEnumerator()

Returns

Type	Description
IEnumerator<Edge>

GetNodeEnumerator()

Declaration

public IEnumerator<Node> GetNodeEnumerator()

Returns

Type	Description
IEnumerator<Node>

InsertEdge(Edge)

Declaration

protected void InsertEdge(Edge e)

Parameters

Type	Name	Description
Edge	e

IsBoundaryNode(int, Coordinate)

Declaration

public bool IsBoundaryNode(int geomIndex, Coordinate coord)

Parameters

Type	Name	Description
int	geomIndex
Coordinate	coord

Returns

Type	Description
bool

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()

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()

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 Nodes

WriteEdges(StreamWriter)

Declaration

public void WriteEdges(StreamWriter outstream)

Parameters

Type	Name	Description
StreamWriter	outstream