com.vividsolutions.jts.triangulate.quadedge

Class Vertex

  • Direct Known Subclasses:
    ConstraintVertex 

    public class Vertex
extends Object
    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.

    • Constructor Detail

      • Vertex

        public Vertex(double _x,
              double _y)

      • Vertex

        public Vertex(double _x,
              double _y,
              double _z)

    • Method Detail

      • getX

        public double getX()

      • getY

        public double getY()

      • getZ

        public double getZ()

      • setZ

        public void setZ(double _z)

      • getCoordinate

        public Coordinate getCoordinate()

      • toString

        public String toString()

      • equals

        public boolean equals(Vertex _x)

      • equals

        public boolean equals(Vertex _x,
                      double tolerance)

      • isInCircle

        public boolean isInCircle(Vertex a,
                          Vertex b,
                          Vertex c)
        Tests if the vertex is inside the circle defined by the triangle with vertices a, b, c (oriented counter-clockwise).
        Parameters:
        a - a vertex of the triangle
        b - a vertex of the triangle
        c - a vertex of the triangle
        Returns:
        true if this vertex is in the circumcircle of (a,b,c)

      • isCCW

        public final boolean isCCW(Vertex b,
                           Vertex c)
        Tests whether the triangle formed by this vertex and two other vertices is in CCW orientation.
        Parameters:
        b - a vertex
        c - a vertex

      • rightOf

        public final boolean rightOf(QuadEdge e)

      • leftOf

        public final boolean leftOf(QuadEdge e)

      • circumRadiusRatio

        public double circumRadiusRatio(Vertex b,
                                Vertex c)
        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)).
        Parameters:
        b - second vertex of the triangle
        c - third vertex of the triangle
        Returns:
        ratio of circumradius to shortest edge.

      • midPoint

        public Vertex midPoint(Vertex a)
        returns a new vertex that is mid-way between this vertex and another end point.
        Parameters:
        a - the other end point.
        Returns:
        the point mid-way between this and that.

      • circleCenter

        public Vertex circleCenter(Vertex b,
                           Vertex c)
        Computes the centre of the circumcircle of this vertex and two others.
        Parameters:
        b -
        c -
        Returns:
        the Coordinate which is the circumcircle of the 3 points.

      • interpolateZValue

        public double interpolateZValue(Vertex v0,
                                Vertex v1,
                                Vertex v2)
        For this vertex enclosed in a triangle defined by three vertices v0, v1 and v2, interpolate a z value from the surrounding vertices.

      • interpolateZ

        public static double interpolateZ(Coordinate p,
                                  Coordinate v0,
                                  Coordinate v1,
                                  Coordinate v2)
        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).
        Parameters:
        p - the point to interpolate the Z value of
        v0 - a vertex of a triangle containing the p
        v1 - a vertex of a triangle containing the p
        v2 - a vertex of a triangle containing the p
        Returns:
        the interpolated Z-value (height) of the point

      • interpolateZ

        public static double interpolateZ(Coordinate p,
                                  Coordinate p0,
                                  Coordinate p1)
        Computes the interpolated Z-value for a point p lying on the segment p0-p1
        Parameters:
        p -
        p0 -
        p1 -
        Returns:
        the interpolated Z value