Class DirectedEdge
Represents a directed edge in a PlanarGraph. A DirectedEdge may or
may not have a reference to a parent Edge (some applications of
planar graphs may not require explicit Edge objects to be created). Usually
a client using a PlanarGraph will subclass DirectedEdge
to add its own application-specific data and methods.
Assembly: NetTopologySuite.dll
Syntax
public class DirectedEdge : GraphComponent, IComparable
Constructors
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DirectedEdge(Node, Node, Coordinate, bool)
Constructs a DirectedEdge connecting the from node to the
to node.
Declaration
public DirectedEdge(Node from, Node to, Coordinate directionPt, bool edgeDirection)
Parameters
| Type |
Name |
Description |
| Node |
from |
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| Node |
to |
|
| Coordinate |
directionPt |
Specifies this DirectedEdge's direction (given by an imaginary
line from the from node to directionPt).
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| bool |
edgeDirection |
Whether this DirectedEdge's direction is the same as or
opposite to that of the parent Edge (if any).
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Fields
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from
Declaration
Field Value
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p0
Declaration
Field Value
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p1
Declaration
Field Value
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parentEdge
Declaration
protected Edge parentEdge
Field Value
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to
Declaration
Field Value
Properties
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Angle
Returns the angle that the start of this DirectedEdge makes with the
positive x-axis, in radians.
Declaration
public double Angle { get; }
Property Value
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Coordinate
Returns the coordinate of the from-node.
Declaration
public Coordinate Coordinate { get; }
Property Value
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DirectionPt
Returns a point to which an imaginary line is drawn from the from-node to
specify this DirectedEdge's orientation.
Declaration
public Coordinate DirectionPt { get; }
Property Value
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Edge
Returns this DirectedEdge's parent Edge, or null if it has none.
Associates this DirectedEdge with an Edge (possibly null, indicating no associated
Edge).
Declaration
public Edge Edge { get; set; }
Property Value
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EdgeDirection
Returns whether the direction of the parent Edge (if any) is the same as that
of this Directed Edge.
Declaration
public bool EdgeDirection { get; protected set; }
Property Value
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FromNode
Returns the node from which this DirectedEdge leaves.
Declaration
public Node FromNode { get; }
Property Value
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IsRemoved
Tests whether this component has been removed from its containing graph.
Declaration
public override bool IsRemoved { get; }
Property Value
Overrides
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Quadrant
Returns 0, 1, 2, or 3, indicating the quadrant in which this DirectedEdge's
orientation lies.
Declaration
[Obsolete("Use QuadrantValue")]
public int Quadrant { get; }
Property Value
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QuadrantEx
Returns 0, 1, 2, or 3, indicating the quadrant in which this DirectedEdge's
orientation lies.
Declaration
public Quadrant QuadrantEx { get; }
Property Value
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Sym
Returns the symmetric DirectedEdge -- the other DirectedEdge associated with
this DirectedEdge's parent Edge.
Sets this DirectedEdge's symmetric DirectedEdge, which runs in the opposite
direction.
Declaration
public DirectedEdge Sym { get; set; }
Property Value
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ToNode
Returns the node to which this DirectedEdge goes.
Declaration
public Node ToNode { get; }
Property Value
Methods
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CompareDirection(DirectedEdge)
Returns 1 if this DirectedEdge has a greater angle with the
positive x-axis than b", 0 if the DirectedEdges are collinear, and -1 otherwise.
Using the obvious algorithm of simply computing the angle is not robust,
since the angle calculation is susceptible to round off. A robust algorithm
is:
first compare the quadrants. If the quadrants are different, it it
trivial to determine which vector is "greater".
if the vectors lie in the same quadrant, the robust
RobustCGAlgorithms.ComputeOrientation(Coordinate, Coordinate, Coordinate)
function can be used to decide the relative orientation of the vectors.
Declaration
public int CompareDirection(DirectedEdge e)
Parameters
Returns
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CompareTo(object)
Returns 1 if this DirectedEdge has a greater angle with the
positive x-axis than b", 0 if the DirectedEdges are collinear, and -1 otherwise.
Using the obvious algorithm of simply computing the angle is not robust,
since the angle calculation is susceptible to round off. A robust algorithm
is:
first compare the quadrants. If the quadrants are different, it it
trivial to determine which vector is "greater".
if the vectors lie in the same quadrant, the robust
RobustCGAlgorithms.ComputeOrientation(Coordinate, Coordinate, Coordinate)
function can be used to decide the relative orientation of the vectors.
Declaration
public int CompareTo(object obj)
Parameters
| Type |
Name |
Description |
| object |
obj |
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Returns
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ToEdges(IList<DirectedEdge>)
Returns a List containing the parent Edge (possibly null) for each of the given
DirectedEdges.
Declaration
public static IList<Edge> ToEdges(IList<DirectedEdge> dirEdges)
Parameters
Returns
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ToString()
Declaration
public override string ToString()
Returns
Overrides
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Write(StreamWriter)
Writes a detailed string representation of this DirectedEdge to the given PrintStream.
Declaration
public void Write(StreamWriter outstream)
Parameters
Implements