Class PolygonizeGraph

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 DirectedEdges is used to indicate that a directed edge has be logically deleted from the graph.

Inheritance

Object

PlanarGraph

PolygonizeGraph

Inherited Members

PlanarGraph.dirEdges

PlanarGraph.nodeMap

PlanarGraph.FindNode(Coordinate)

PlanarGraph.Add(Node)

PlanarGraph.Add(Edge)

PlanarGraph.Add(DirectedEdge)

PlanarGraph.GetNodeEnumerator()

PlanarGraph.Nodes

PlanarGraph.GetDirEdgeEnumerator()

PlanarGraph.GetEdgeEnumerator()

PlanarGraph.Edges

PlanarGraph.Remove(Edge)

PlanarGraph.Remove(DirectedEdge)

PlanarGraph.Remove(Node)

PlanarGraph.FindNodesOfDegree(Int32)

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: NetTopologySuite.Operation.Polygonize

Assembly: NetTopologySuite.dll

Syntax

public class PolygonizeGraph : PlanarGraph

Constructors

PolygonizeGraph(GeometryFactory)

Create a new polygonization graph.

Declaration

public PolygonizeGraph(GeometryFactory factory)

Parameters

Type	Name	Description
GeometryFactory	factory

Methods

AddEdge(LineString)

Add a LineString forming an edge of the polygon graph.

Declaration

public void AddEdge(LineString line)

Parameters

Type	Name	Description
LineString	line	The line to add.

ComputeDepthParity()

Traverses the polygonized edge rings in the graph and computes the depth parity (odd or even) relative to the exterior of the graph.

If the client has requested that the output be polygonally valid, only odd polygons will be constructed.

Declaration

public void ComputeDepthParity()

DeleteAllEdges(Node)

Deletes all edges at a node.

Declaration

public static void DeleteAllEdges(Node node)

Parameters

Type	Name	Description
Node	node

DeleteCutEdges()

Finds and removes all cut edges from the graph.

Declaration

public IList<LineString> DeleteCutEdges()

Returns

Type	Description
IList<LineString>	A list of the LineStrings forming the removed cut edges.

DeleteDangles()

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.

Declaration

public ICollection<LineString> DeleteDangles()

Returns

Type	Description
ICollection<LineString>	A List containing the LineStrings that formed dangles.

GetEdgeRings()

Computes the minimal EdgeRings formed by the edges in this graph.

Declaration

public IList<EdgeRing> GetEdgeRings()

Returns

Type	Description
IList<EdgeRing>	A list of the{EdgeRings found by the polygonization process.