/*
* 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.linemerge;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.CoordinateArrays;
import org.locationtech.jts.geom.LineString;
import org.locationtech.jts.planargraph.DirectedEdge;
import org.locationtech.jts.planargraph.Edge;
import org.locationtech.jts.planargraph.Node;
import org.locationtech.jts.planargraph.PlanarGraph;
/**
* A planar graph of edges that is analyzed to sew the edges together. The
* <code>marked</code> flag on {@link org.locationtech.jts.planargraph.Edge}s
* and {@link org.locationtech.jts.planargraph.Node}s indicates whether they have been
* logically deleted from the graph.
*
* @version 1.7
*/
public class LineMergeGraph extends PlanarGraph
{
/**
* Adds an Edge, DirectedEdges, and Nodes for the given LineString representation
* of an edge.
* Empty lines or lines with all coordinates equal are not added.
*
* @param lineString the linestring to add to the graph
*/
public void addEdge(LineString lineString) {
if (lineString.isEmpty()) { return; }
Coordinate[] coordinates = CoordinateArrays.removeRepeatedPoints(lineString.getCoordinates());
// don't add lines with all coordinates equal
if (coordinates.length <= 1) return;
Coordinate startCoordinate = coordinates[0];
Coordinate endCoordinate = coordinates[coordinates.length - 1];
Node startNode = getNode(startCoordinate);
Node endNode = getNode(endCoordinate);
DirectedEdge directedEdge0 = new LineMergeDirectedEdge(startNode, endNode,
coordinates[1], true);
DirectedEdge directedEdge1 = new LineMergeDirectedEdge(endNode, startNode,
coordinates[coordinates.length - 2], false);
Edge edge = new LineMergeEdge(lineString);
edge.setDirectedEdges(directedEdge0, directedEdge1);
add(edge);
}
private Node getNode(Coordinate coordinate) {
Node node = findNode(coordinate);
if (node == null) {
node = new Node(coordinate);
add(node);
}
return node;
}
}