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/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2011, Open Source Geospatial Foundation (OSGeo)
* (C) 2003-2005, Open Geospatial Consortium Inc.
*
* All Rights Reserved. http://www.opengis.org/legal/
*/
package org.opengis.geometry.primitive;
import static org.opengis.annotation.Obligation.*;
import static org.opengis.annotation.Specification.*;
import org.opengis.annotation.Association;
import org.opengis.annotation.UML;
import org.opengis.geometry.coordinate.GenericCurve;
import org.opengis.geometry.coordinate.PointArray;
/**
* Defines a homogeneous segment of a {@linkplain Curve curve}. Each {@code CurveSegment} shall be
* in, at most, one {@linkplain Curve curve}.
*
* @version ISO 19107
* @author Martin Desruisseaux (IRD)
* @since GeoAPI 1.0
*/
@UML(identifier = "GM_CurveSegment", specification = ISO_19107)
public interface CurveSegment extends GenericCurve {
/**
* Returns the curve which own this curve segment. This method is optional since the
* association in ISO 19107 is navigable only from {@code Curve} to {@code CurveSegment}, not
* the other way.
*
*
*
* NOTE: In the specification, curve segments do not appear
* except in the context of a curve, and therefore this method should never returns {@code null}
* which would preclude the use of curve segments except in this manner. While this would not
* affect the specification, allowing {@code null} owner allows other standards based on ISO
* 19107 one to use curve segments in a more open-ended manner.
*
*
*
* @return The owner of this curve segment, or {@code null} if the association is not available
* or not implemented that way.
* @see Curve#getSegments
* @see SurfacePatch#getSurface
* @issue http://jira.codehaus.org/browse/GEO-63
*/
@Association("Segmentation")
@UML(identifier = "curve", obligation = OPTIONAL, specification = ISO_19107)
Curve getCurve();
/**
* Specifies the curve interpolation mechanism used for this segment. This mechanism uses the
* control points and control parameters to determine the position of this {@code CurveSegment}.
*
* @return The interpolation mechanism used for this segment.
*/
@UML(identifier = "interpolation", obligation = MANDATORY, specification = ISO_19107)
CurveInterpolation getInterpolation();
/**
* Specifies the type of continuity between this curve segment and its immediate neighbors. If
* this is the first curve segment in the curve, this value is ignored.
*
*
*
* NOTE: Use of these values is only appropriate when the basic
* curve definition is an underdetermined system. For example, line strings and segments cannot
* support continuity above C0, since there is no spare control parameter to adjust
* the incoming angle at the end points of the segment. Spline functions on the other hand often
* have extra degrees of freedom on end segments that allow them to adjust the values of the
* derivatives to support C1 or higher continuity.
*
*
*
* @return The type of continuity between this curve semgent and its immediate neighbors.
* @see #getNumDerivativesInterior
* @see #getNumDerivativesAtEnd
*/
@UML(identifier = "numDerivativesAtStart", obligation = MANDATORY, specification = ISO_19107)
int getNumDerivativesAtStart();
/**
* Specifies the type of continuity that is guaranteed interior to the curve. The default value
* of "0" means simple continuity, which is a mandatory minimum level of continuity. This level
* is referred to as "C0" in mathematical texts. A value of 1 means that the function
* and its first derivative are continuous at the appropriate end point: "C1"
* continuity. A value of "n" for any integer means the function and its first n
* derivatives are continuous: "Cn" continuity.
*
* @return The type of continuity that is guaranteed interior to the curve.
* @see #getNumDerivativesAtStart
* @see #getNumDerivativesAtEnd
*/
@UML(identifier = "numDerivativesInterior", obligation = MANDATORY, specification = ISO_19107)
int getNumDerivativesInterior();
/**
* Specifies the type of continuity between this curve segment and its immediate neighbors. If
* this is the last curve segment in the curve, this value is ignored.
*
*
*
* NOTE: Use of these values is only appropriate when the basic
* curve definition is an underdetermined system. For example, line strings and segments cannot
* support continuity above C0, since there is no spare control parameter to adjust
* the incoming angle at the end points of the segment. Spline functions on the other hand often
* have extra degrees of freedom on end segments that allow them to adjust the values of the
* derivatives to support C1 or higher continuity.
*
*
*
* @return The type of continuity between this curve semgent and its immediate neighbors.
* @see #getNumDerivativesAtStart
* @see #getNumDerivativesInterior
*/
@UML(identifier = "numDerivativesAtEnd", obligation = MANDATORY, specification = ISO_19107)
int getNumDerivativesAtEnd();
/**
* Returns an ordered array of point values that lie on the {@linkplain CurveSegment curve
* segment}. In most cases, these will be related to control points used in the construction of
* the segment. The control points of a curve segment are use to control its shape, and are not
* always on the curve segment itself. For example in a spline curve, the curve segment is given
* as a weighted vector sum of the control points. Each weight function will have a maximum
* within the constructive parameter interval, which will roughly correspond to the point on the
* curve where it passes closest that the corresponding control point. These points, the values
* of the curve at the maxima of the weight functions, will be the sample points for the curve
* segment.
*
* @return The control points.
*/
@UML(identifier = "samplePoint", obligation = MANDATORY, specification = ISO_19107)
PointArray getSamplePoints();
/**
* Returns an ordered pair of points, which are the start point and end point of the curve. This
* method operates with the same semantics as that on {@linkplain Curve#getBoundary curve}
* except that the end points of a {@code CurveSegment} are not necessarily existing {@linkplain
* Point points} and thus the boundary may contain transient {@linkplain Point points}.
*
*
*
* NOTE: The above {@linkplain CurveBoundary curve boundary} will
* almost always be two distinct positions, but, like {@linkplain Curve curves}, {@code
* CurveSegment}s can be cycles in themselves. The most likely scenario is that all of the
* points used will be transients (constructed to support the return value), except for the
* start point and end point of the aggregated {@linkplain Curve curve}. These two positions, in
* the case where the {@linkplain Curve curve} is involved in a {@linkplain
* org.opengis.geometry.complex.Complex complex}, will be represented as {@linkplain Point
* points} in the same {@linkplain org.opengis.geometry.complex.Complex complex}.
*
*
*
* @return The sets of positions on the boundary.
*/
@UML(identifier = "boundary", obligation = MANDATORY, specification = ISO_19107)
CurveBoundary getBoundary();
/**
* Reverses the orientation of the parameterizations of the segment.
*
* @return The reverse of this curve segment.
*/
@UML(identifier = "reverse", obligation = MANDATORY, specification = ISO_19107)
CurveSegment reverse();
}