/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2001-2006 Vivid Solutions
* (C) 2001-2008, Open Source Geospatial Foundation (OSGeo)
*
* 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;
* version 2.1 of the License.
*
* 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.
*/
package org.geotools.geometry.iso.operation.overlay;
import java.util.ArrayList;
import java.util.List;
import org.geotools.geometry.iso.topograph2D.DirectedEdge;
import org.geotools.geometry.iso.topograph2D.DirectedEdgeStar;
import org.geotools.geometry.iso.topograph2D.EdgeRing;
import org.geotools.geometry.iso.topograph2D.Node;
import org.geotools.geometry.iso.util.algorithm2D.CGAlgorithms;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
/**
* A ring of {@link org.geotools.geometry.iso.topograph2D.Edge}s which may contain nodes of degree > 2. A
* MaximalEdgeRing may represent two different spatial entities:
* <ul>
* <li>a single polygon possibly containing inversions (if the ring is oriented
* CW)
* <li>a single hole possibly containing exversions (if the ring is oriented
* CCW)
* </ul>
* If the MaximalEdgeRing represents a polygon, the interior of the polygon is
* strongly connected.
* <p>
* These are the form of rings used to define polygons under some spatial data
* models. However, under the OGC SFS model, {@link MinimalEdgeRing} are
* required. A MaximalEdgeRing can be converted to a list of MinimalEdgeRings
* using the {@link #buildMinimalRings() } method.
*
*
*
*
*
* @source $URL$
*/
public class MaximalEdgeRing extends EdgeRing {
public MaximalEdgeRing(DirectedEdge start,
CoordinateReferenceSystem crs, CGAlgorithms cga) {
super(start, crs, cga);
}
public DirectedEdge getNext(DirectedEdge de) {
return de.getNext();
}
public void setEdgeRing(DirectedEdge de, EdgeRing er) {
de.setEdgeRing(er);
}
/**
* For all nodes in this EdgeRing, link the DirectedEdges at the node to
* form minimalEdgeRings
*/
public void linkDirectedEdgesForMinimalEdgeRings() {
DirectedEdge de = startDe;
do {
Node node = de.getNode();
((DirectedEdgeStar) node.getEdges()).linkMinimalDirectedEdges(this);
de = de.getNext();
} while (de != startDe);
}
public List buildMinimalRings() {
List minEdgeRings = new ArrayList();
DirectedEdge de = startDe;
do {
if (de.getMinEdgeRing() == null) {
EdgeRing minEr = new MinimalEdgeRing(de,
super.crs, cga);
minEdgeRings.add(minEr);
}
de = de.getNext();
} while (de != startDe);
return minEdgeRings;
}
}