/*
* 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.coordinate;
import java.util.List;
import org.opengis.geometry.primitive.CurveInterpolation;
import org.opengis.geometry.primitive.CurveSegment;
import org.opengis.annotation.UML;
import static org.opengis.annotation.Obligation.*;
import static org.opengis.annotation.Specification.*;
/**
* Similar to a {@linkplain LineString line string} except that the interpolation is
* by circular arcs. Since it requires 3 points to determine a circular arc, the
* {@linkplain #getControlPoints control points} are treated as a sequence of overlapping
* sets of 3 {@linkplain Position positions}, the start of each arc, some point between the
* start and end, and the end of each arc. Since the end of each arc is the start of the next,
* this {@linkplain Position position} is not repeated in the {@linkplain #getControlPoints
* control points} sequence.
*
*
* @source $URL: http://svn.osgeo.org/geotools/branches/2.7.x/modules/library/opengis/src/main/java/org/opengis/geometry/coordinate/ArcString.java $
* @version <A HREF="http://www.opengeospatial.org/standards/as">ISO 19107</A>
* @author Martin Desruisseaux (IRD)
* @since GeoAPI 1.0
*
* @see GeometryFactory#createArcString
* @see ArcStringByBulge#asArcString
*/
@UML(identifier="GM_ArcString", specification=ISO_19107)
public interface ArcString extends CurveSegment {
/**
* Returns the number of circular arcs in the string. Since the interpolation method
* requires overlapping sets of 3 positions, the number of arcs determines the number
* of {@linkplain #getControlPoints control points}:
*
* <blockquote>
* <pre>numArc = ({@link #getControlPoints controlPoints}.length - 1)/2</pre>
* </blockquote>
*
* @return The number of circular arcs.
*/
@UML(identifier="numArc", obligation=MANDATORY, specification=ISO_19107)
int getNumArc();
/**
* Returns the sequence of points used to control the arcs in this string. The first three
* {@linkplain Position positions} in the sequence determines the first arc. Any three
* consecutive {@linkplain Position positions} beginning with an odd offset, determine
* another arc in the string.
*
* @return The control points. The array size is <code>2*{@link #getNumArc numArc} +1</code>.
*/
@UML(identifier="controlPoints", obligation=MANDATORY, specification=ISO_19107)
PointArray getControlPoints();
/**
* The interpolation for a {@code ArcString} is
* "{@linkplain CurveInterpolation#CIRCULAR_ARC_3_POINTS circular arc by 3 points}".
*
* @return Always {@link CurveInterpolation#CIRCULAR_ARC_3_POINTS}.
*/
@UML(identifier="interpolation", obligation=MANDATORY, specification=ISO_19107)
CurveInterpolation getInterpolation();
/**
* Constructs a sequence of arcs that is the geometric equivalent of this arc string.
*
* @return The sequence of arcs.
*/
@UML(identifier="asGM_Arc", obligation=MANDATORY, specification=ISO_19107)
List<Arc> asArcs();
}