Package org.locationtech.jts.operation.distance3d

Class PlanarPolygon3D

java.lang.Object

org.locationtech.jts.operation.distance3d.PlanarPolygon3D

public class PlanarPolygon3D
extends java.lang.Object

Models a polygon lying in a plane in 3-dimensional Cartesian space. The polygon representation is supplied by a Polygon, containing coordinates with XYZ ordinates. 3D polygons are assumed to lie in a single plane. The plane best fitting the polygon coordinates is computed and is represented by a Plane3D.

Field Summary

Fields

Modifier and Type	Field	Description
private int	facingPlane
private Plane3D	plane
private Polygon	poly

Constructor Summary

Constructors

Constructor	Description
PlanarPolygon3D(Polygon poly)

Method Summary

Modifier and Type	Method	Description
private Vector3D	averageNormal(CoordinateSequence seq)	Computes an average normal vector from a list of polygon coordinates.
private Coordinate	averagePoint(CoordinateSequence seq)	Computes a point which is the average of all coordinates in a sequence.
private Plane3D	findBestFitPlane(Polygon poly)	Finds a best-fit plane for the polygon, by sampling a few points from the exterior ring.
Plane3D	getPlane()
Polygon	getPolygon()
boolean	intersects(Coordinate intPt)
boolean	intersects(Coordinate pt, LineString ring)
private int	locate(Coordinate pt, LineString ring)
private static Coordinate	project(Coordinate p, int facingPlane)
private static CoordinateSequence	project(CoordinateSequence seq, int facingPlane)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

plane

private Plane3D plane

poly

private Polygon poly

facingPlane

private int facingPlane

Constructor Detail

PlanarPolygon3D

public PlanarPolygon3D(Polygon poly)

Method Detail

findBestFitPlane

private Plane3D findBestFitPlane(Polygon poly)

Finds a best-fit plane for the polygon, by sampling a few points from the exterior ring.

The algorithm used is Newell's algorithm: - a base point for the plane is determined from the average of all vertices - the normal vector is determined by computing the area of the projections on each of the axis planes

Parameters:

poly - the polygon to determine the plane for

Returns:

the best-fit plane

averageNormal

private Vector3D averageNormal(CoordinateSequence seq)

Computes an average normal vector from a list of polygon coordinates. Uses Newell's method, which is based on the fact that the vector with components equal to the areas of the projection of the polygon onto the Cartesian axis planes is normal.

Parameters:

seq - the sequence of coordinates for the polygon

Returns:

a normal vector

averagePoint

private Coordinate averagePoint(CoordinateSequence seq)

Computes a point which is the average of all coordinates in a sequence. If the sequence lies in a single plane, the computed point also lies in the plane.

Parameters:

seq - a coordinate sequence

Returns:

a Coordinate with averaged ordinates

getPlane

public Plane3D getPlane()

getPolygon

public Polygon getPolygon()

intersects

public boolean intersects(Coordinate intPt)

locate

private int locate(Coordinate pt,
                   LineString ring)

intersects

public boolean intersects(Coordinate pt,
                          LineString ring)

project

private static CoordinateSequence project(CoordinateSequence seq,
                                          int facingPlane)

project

private static Coordinate project(Coordinate p,
                                  int facingPlane)