001 /*
002 * GeoAPI - Java interfaces for OGC/ISO standards
003 * http://www.geoapi.org
004 *
005 * Copyright (C) 2005-2012 Open Geospatial Consortium, Inc.
006 * All Rights Reserved. http://www.opengeospatial.org/ogc/legal
007 *
008 * Permission to use, copy, and modify this software and its documentation, with
009 * or without modification, for any purpose and without fee or royalty is hereby
010 * granted, provided that you include the following on ALL copies of the software
011 * and documentation or portions thereof, including modifications, that you make:
012 *
013 * 1. The full text of this NOTICE in a location viewable to users of the
014 * redistributed or derivative work.
015 * 2. Notice of any changes or modifications to the OGC files, including the
016 * date changes were made.
017 *
018 * THIS SOFTWARE AND DOCUMENTATION IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE
019 * NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
020 * TO, WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT
021 * THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY THIRD PARTY
022 * PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS.
023 *
024 * COPYRIGHT HOLDERS WILL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL OR
025 * CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE SOFTWARE OR DOCUMENTATION.
026 *
027 * The name and trademarks of copyright holders may NOT be used in advertising or
028 * publicity pertaining to the software without specific, written prior permission.
029 * Title to copyright in this software and any associated documentation will at all
030 * times remain with copyright holders.
031 */
032 package org.opengis.geometry.coordinate;
033
034 import java.util.List;
035 import org.opengis.annotation.UML;
036
037 import static org.opengis.annotation.Obligation.*;
038 import static org.opengis.annotation.Specification.*;
039
040
041 /**
042 * A planar polygon defined by 3 corners. That is, a triangle would be the result of a constructor
043 * of the form: {@code Polygon(LineString({P1, P2, P3, P1}))} where <var>P</var><sub>1</sub>,
044 * <var>P</var><sub>2</sub>, and <var>P</var><sub>3</sub> are three {@linkplain Position positions}.
045 * Triangles have no holes. Triangle shall be used to construct
046 * {@linkplain TriangulatedSurface triangulated surfaces}.
047 * <p>
048 * <strong>Note:</strong> The points in a triangle can be located in terms of their corner points
049 * by defining a set of barycentric coordinates, three nonnegative numbers <var>c</var><sub>1</sub>,
050 * <var>c</var><sub>2</sub>, and <var>c</var><sub>3</sub> such that
051 *
052 * <var>c</var><sub>1</sub> + <var>c</var><sub>2</sub> + <var>c</var><sub>3</sub> = 1.0.
053 *
054 * Then, each point <var>P</var> in the triangle can be expressed for some set of barycentric coordinates as:
055 * <p>
056 * <blockquote>
057 * P = <var>c</var><sub>1</sub><var>P</var><sub>1</sub> +
058 * <var>c</var><sub>2</sub><var>P</var><sub>2</sub> +
059 * <var>c</var><sub>3</sub><var>P</var><sub>3</sub>
060 * </blockquote>
061 *
062 * @version <A HREF="http://www.opengeospatial.org/standards/as">ISO 19107</A>
063 * @author Martin Desruisseaux (IRD)
064 * @since GeoAPI 2.0
065 */
066 @UML(identifier="GM_Triangle", specification=ISO_19107)
067 public interface Triangle extends Polygon {
068 /**
069 * Returns the triangle corner. The list must contains exactly 3 elements.
070 */
071 @UML(identifier="corners", obligation=MANDATORY, specification=ISO_19107)
072 List<Position> getCorners();
073
074 /**
075 * Returns the patch which own this surface patch.
076 */
077 @UML(identifier="surface", obligation=MANDATORY, specification=ISO_19107)
078 TriangulatedSurface getSurface();
079 }