/* * The JTS Topology Suite is a collection of Java classes that * implement the fundamental operations required to validate a given * geo-spatial data set to a known topological specification. * * Copyright (C) 2001 Vivid Solutions * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * For more information, contact: * * Vivid Solutions * Suite #1A * 2328 Government Street * Victoria BC V8T 5G5 * Canada * * (250)385-6040 * www.vividsolutions.com */ package com.vividsolutions.jts.math; import com.vividsolutions.jts.geom.Coordinate; /** * Models a plane in 3-dimensional Cartesian space. * * @author mdavis * */ public class Plane3D { /** * Enums for the 3 coordinate planes */ public static final int XY_PLANE = 1; public static final int YZ_PLANE = 2; public static final int XZ_PLANE = 3; private Vector3D normal; private Coordinate basePt; public Plane3D(Vector3D normal, Coordinate basePt) { this.normal = normal; this.basePt = basePt; } /** * Computes the oriented distance from a point to the plane. * The distance is: * <ul> * <li><b>positive</b> if the point lies above the plane (relative to the plane normal) * <li><b>zero</b> if the point is on the plane * <li><b>negative</b> if the point lies below the plane (relative to the plane normal) * </ul> * * @param p the point to compute the distance for * @return the oriented distance to the plane */ public double orientedDistance(Coordinate p) { Vector3D pb = new Vector3D(p, basePt); double pbdDotNormal = pb.dot(normal); if (Double.isNaN(pbdDotNormal)) throw new IllegalArgumentException("3D Coordinate has NaN ordinate"); double d = pbdDotNormal / normal.length(); return d; } /** * Computes the axis plane that this plane lies closest to. * <p> * Geometries lying in this plane undergo least distortion * (and have maximum area) * when projected to the closest axis plane. * This provides optimal conditioning for * computing a Point-in-Polygon test. * * @return the index of the closest axis plane. */ public int closestAxisPlane() { double xmag = Math.abs(normal.getX()); double ymag = Math.abs(normal.getY()); double zmag = Math.abs(normal.getZ()); if (xmag > ymag) { if (xmag > zmag) return YZ_PLANE; else return XY_PLANE; } // y >= x else if (zmag > ymag) { return XY_PLANE; } // y >= z return XZ_PLANE; } }