org.locationtech.jts.operation.overlay.MaximalEdgeRing Maven / Gradle / Ivy
/*
* Copyright (c) 2016 Vivid Solutions.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
*
* http://www.eclipse.org/org/documents/edl-v10.php.
*/
package org.locationtech.jts.operation.overlay;
import java.util.ArrayList;
import java.util.List;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.geomgraph.DirectedEdge;
import org.locationtech.jts.geomgraph.DirectedEdgeStar;
import org.locationtech.jts.geomgraph.EdgeRing;
import org.locationtech.jts.geomgraph.Node;
/**
* A ring of {@link DirectedEdge}s which may contain nodes of degree > 2.
* A MaximalEdgeRing may represent two different spatial entities:
*
* - a single polygon possibly containing inversions (if the ring is oriented CW)
*
- a single hole possibly containing exversions (if the ring is oriented CCW)
*
* If the MaximalEdgeRing represents a polygon,
* the interior of the polygon is strongly connected.
*
* These are the form of rings used to define polygons under some spatial data models.
* However, under the OGC SFS model, {@link MinimalEdgeRing}s are required.
* A MaximalEdgeRing can be converted to a list of MinimalEdgeRings using the
* {@link #buildMinimalRings() } method.
*
* @version 1.7
* @see org.locationtech.jts.operation.overlay.MinimalEdgeRing
*/
public class MaximalEdgeRing
extends EdgeRing
{
public MaximalEdgeRing(DirectedEdge start, GeometryFactory geometryFactory) {
super(start, geometryFactory);
}
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, geometryFactory);
minEdgeRings.add(minEr);
}
de = de.getNext();
} while (de != startDe);
return minEdgeRings;
}
}