/*$************************************************************************************************ ** ** $Id: Curve.java,v 1.6 2004/03/19 04:11:44 desruisseaux Exp $ ** ** $Source: /cvsroot/geoapi/src/org/opengis/spatialschema/geometry/primitive/Curve.java,v $ ** ** Copyright (C) 2003 Open GIS Consortium, Inc. All Rights Reserved. http://www.opengis.org/Legal/ ** *************************************************************************************************/package org.opengis.spatialschema.geometry.primitive;// J2SE direct dependenciesimport java.util.List;// OpenGIS direct dependenciesimport org.opengis.spatialschema.geometry.geometry.GenericCurve;/** * Curve with a positive orientation. <code>Curve</code> is * a descendent subtype of {@link Primitive} through {@link OrientablePrimitive}. It is the basis * for 1-dimensional geometry. A curve is a continuous image of an open interval and so could be * written as a parameterized function such as * * <code>c(t):(a,&nbsp;b) &rarr; E<sup>n</sup></code> * * where "t" is a real parameter and E<sup>n</sup> is Euclidean space of dimension <var>n</var> * (usually 2 or 3, as determined by the coordinate reference system). Any other parameterization * that results in the same image curve, traced in the same direction, such as any linear shifts * and positive scales such as * * <code>e(t) = c(a&nbsp;+&nbsp;t(b-a)):(0,1) &rarr; E<sup>n</sup></code>, * * is an equivalent representation of the same curve. For the sake of simplicity, <code>Curve</code>s * should be parameterized by arc length, so that the parameterization operation inherited from * {@link GenericCurve} will be valid for parameters between 0 and the length of the curve. * <br><br> * Curves are continuous, connected, and have a measurable length in terms of the coordinate system. * The orientation of the curve is determined by this parameterization, and is consistent with the * tangent function, which approximates the derivative function of the parameterization and shall * always point in the "forward" direction. The parameterization of the reversal of the curve defined * by * * <code>c(t):(a,&nbsp;b) &rarr; E<sup>n</sup></code> * * would be defined by a function of the form * * <code>s(t) = c(a&nbsp;+&nbsp;b&nbsp;-&nbsp;t):(a,&nbsp;b) &rarr; E<sup>n</sup></code>. * * <br><br> * A curve is composed of one or more curve segments. Each curve segment within a curve may be * defined using a different interpolation method. The curve segments are connected to one another, * with the end point of each segment except the last being the start point of the next segment in * the segment list. * * @UML type GM_Curve * @author ISO/DIS 19107 * @author <A HREF="http://www.opengis.org">OpenGIS&reg; consortium</A> * @version 2.0 * * @see PrimitiveFactory#createCurve */public interface Curve extends OrientableCurve, GenericCurve {    /**     * Lists the components {@linkplain CurveSegment curve segments} of <code>Curve</code>, each     * of which defines the direct position of points along a portion of the curve. The order of     * the {@linkplain CurveSegment curve segments} is the order in which they are used to trace     * this <code>Curve</code>. For a particular parameter interval, the <code>Curve</code> and     * {@link CurveSegment} agree.     *     * @return The list of curve segments. Should never be <code>null</code> neither empty.     * @UML association segment     *     * @see CurveSegment#getCurve     */    public List getSegments();}