Class Vertex

Models a site (node) in a QuadEdgeSubdivision. The sites can be points on a line string representing a linear site.

The vertex can be considered as a vector with a norm, length, inner product, cross product, etc. Additionally, point relations (e.g., is a point to the left of a line, the circle defined by this point and two others, etc.) are also defined in this class.

It is common to want to attach user-defined data to the vertices of a subdivision. One way to do this is to subclass Vertex to carry any desired information.

Inheritance

object

Vertex

ConstraintVertex

Implements

IEquatable<Vertex>

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: NetTopologySuite.Triangulate.QuadEdge

Assembly: NetTopologySuite.dll

Syntax

public class Vertex : IEquatable<Vertex>

Constructors

Vertex(Coordinate)

Creates an instance of this class using a clone of the given Coordinate.

Declaration

public Vertex(Coordinate p)

Parameters

Type	Name	Description
Coordinate	p	The coordinate

Vertex(double, double)

Creates an instance of this class using the given x- and y-ordinate valuse

Declaration

public Vertex(double x, double y)

Parameters

Type	Name	Description
double	x	x-ordinate value
double	y	y-ordinate value

Vertex(double, double, double)

Creates an instance of this class using the given x-, y- and z-ordinate values

Declaration

public Vertex(double x, double y, double z)

Parameters

Type	Name	Description
double	x	x-ordinate value
double	y	y-ordinate value
double	z	z-ordinate value

Properties

Coordinate

Gets the coordinate

Declaration

public Coordinate Coordinate { get; }

Property Value

Type	Description
Coordinate

X

Gets the x-ordinate value

Declaration

public double X { get; }

Property Value

Type	Description
double

Y

Gets the y-ordinate value

Declaration

public double Y { get; }

Property Value

Type	Description
double

Z

Gets the z-ordinate value

Declaration

public double Z { get; set; }

Property Value

Type	Description
double

Methods

CircleCenter(Vertex, Vertex)

Computes the centre of the circumcircle of this vertex and two others.

Declaration

public Vertex CircleCenter(Vertex b, Vertex c)

Parameters

Type	Name	Description
Vertex	b
Vertex	c

Returns

Type	Description
Vertex	the Coordinate which is the circumcircle of the 3 points.

CircumRadiusRatio(Vertex, Vertex)

Computes the value of the ratio of the circumradius to shortest edge. If smaller than some given tolerance B, the associated triangle is considered skinny. For an equal lateral triangle this value is 0.57735. The ratio is related to the minimum triangle angle theta by: circumRadius/shortestEdge = 1/(2sin(theta)).

Declaration

public double CircumRadiusRatio(Vertex b, Vertex c)

Parameters

Type	Name	Description
Vertex	b	second vertex of the triangle
Vertex	c	third vertex of the triangle

Returns

Type	Description
double	ratio of circumradius to shortest edge.

Classify(Vertex, Vertex)

Declaration

public int Classify(Vertex p0, Vertex p1)

Parameters

Type	Name	Description
Vertex	p0
Vertex	p1

Returns

Type	Description
int

Equals(Vertex)

Declaration

public bool Equals(Vertex x)

Parameters

Type	Name	Description
Vertex	x

Returns

Type	Description
bool

Equals(Vertex, double)

Declaration

public bool Equals(Vertex x, double tolerance)

Parameters

Type	Name	Description
Vertex	x
double	tolerance

Returns

Type	Description
bool

InterpolateZ(Coordinate, Coordinate, Coordinate)

Computes the interpolated Z-value for a point p lying on the segment p0-p1

Declaration

public static double InterpolateZ(Coordinate p, Coordinate p0, Coordinate p1)

Parameters

Type	Name	Description
Coordinate	p	The point to interpolate the Z value of
Coordinate	p0	A vertex of the segment p is lying on
Coordinate	p1	A vertex of the segment p is lying on

Returns

Type	Description
double	The interpolated Z-value (height) of the point

InterpolateZ(Coordinate, Coordinate, Coordinate, Coordinate)

Interpolates the Z-value (height) of a point enclosed in a triangle whose vertices all have Z values. The containing triangle must not be degenerate (in other words, the three vertices must enclose a non-zero area).

Declaration

public static double InterpolateZ(Coordinate p, Coordinate v0, Coordinate v1, Coordinate v2)

Parameters

Type	Name	Description
Coordinate	p	The point to interpolate the Z value of
Coordinate	v0	A vertex of a triangle containing the p
Coordinate	v1	A vertex of a triangle containing the p
Coordinate	v2	A vertex of a triangle containing the p

Returns

Type	Description
double	The interpolated Z-value (height) of the point

InterpolateZValue(Vertex, Vertex, Vertex)

For this vertex enclosed in a triangle defined by three vertices v0, v1 and v2, interpolate a z value from the surrounding vertices.

Declaration

public double InterpolateZValue(Vertex v0, Vertex v1, Vertex v2)

Parameters

Type	Name	Description
Vertex	v0
Vertex	v1
Vertex	v2

Returns

Type	Description
double

IsInCircle(Vertex, Vertex, Vertex)

Tests if this is inside the circle defined by the points a, b, c. This test uses simple double-precision arithmetic, and thus may not be robust.

Declaration

public bool IsInCircle(Vertex a, Vertex b, Vertex c)

Parameters

Type	Name	Description
Vertex	a	A vertex of the triangle
Vertex	b	A vertex of the triangle
Vertex	c	A vertex of the triangle

Returns

Type	Description
bool	true if this vertex is inside the circumcircle (a, b, c)

MidPoint(Vertex)

returns a new vertex that is mid-way between this vertex and another end point.

Declaration

public Vertex MidPoint(Vertex a)

Parameters

Type	Name	Description
Vertex	a	the other end point.

Returns

Type	Description
Vertex	the point mid-way between this and that.

ToString()

Declaration

public override string ToString()

Returns

Type	Description
string

Overrides

object.ToString()

Implements

IEquatable<T>