/* Spatial Operations & Editing Tools for uDig
*
* Axios Engineering under a funding contract with:
* Diputación Foral de Gipuzkoa, Ordenación Territorial
*
* http://b5m.gipuzkoa.net
* http://www.axios.es
*
* (C) 2006, Diputación Foral de Gipuzkoa, Ordenación Territorial (DFG-OT).
* DFG-OT agrees to license under Lesser General Public License (LGPL).
*
* 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 es.axios.lib.geometry.split;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Logger;
import com.vividsolutions.jts.algorithm.CGAlgorithms;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.CoordinateArrays;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryCollection;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.LineString;
import com.vividsolutions.jts.geom.LinearRing;
import com.vividsolutions.jts.geom.MultiLineString;
import com.vividsolutions.jts.geom.MultiPoint;
import com.vividsolutions.jts.geom.MultiPolygon;
import com.vividsolutions.jts.geom.Point;
import com.vividsolutions.jts.geom.Polygon;
import com.vividsolutions.jts.geomgraph.DirectedEdge;
import es.axios.lib.geometry.split.RingExtractor.ResultRingExtractor;
import es.axios.udig.ui.commons.internal.i18n.Messages;
/**
* Performs a split of a LineString, MultiLineString, Polygon or MultiPolygon
* using a provided LineString as cutting edge.
*
* @author Mauricio Pazos (www.axios.es)
* @author Aritz Davila (www.axios.es)
* @since 1.1.0
*/
public class SplitStrategy {
private static final Logger LOGGER = Logger.getLogger(SplitStrategy.class.getName());
/** The split line. */
private final LineString splitLine;
/** Valid strategies for split geometries. */
private final Map<Class<?>, SpecificSplitOp> strategies;
/**
* Constructor for splitStrategy.
*
* @param splitLine
* The split line.
*/
public SplitStrategy(final LineString splitLine) {
assert splitLine != null : "should not be null"; //$NON-NLS-1$
this.splitLine = splitLine;
this.strategies = new HashMap<Class<?>, SplitStrategy.SpecificSplitOp>(
4);
this.strategies.put(LineString.class, new LineStringSplitter());
this.strategies.put(MultiLineString.class,
new MultiLineStringSplitter());
this.strategies.put(Polygon.class, new PolygonSplitter());
this.strategies.put(MultiPolygon.class, new MultiPolygonSplitter());
}
/**
* @return the original split line
*/
public LineString getSplitLine() {
return this.splitLine;
}
/**
* @param geomToSplit
* @return A list of the resultant geometries.
*/
public List<Geometry> split(final Geometry geomToSplit) {
assert !((geomToSplit instanceof Point) || (geomToSplit instanceof MultiPoint)) : "cannot split point or multipoint"; //$NON-NLS-1$
Class<?> geometryClass = geomToSplit.getClass();
SpecificSplitOp splitOp = findSplitStrategy(geometryClass);
UsefulSplitLineBuilder usefulSplitLineBuilder = UsefulSplitLineBuilder.newInstance(getSplitLine());
LOGGER.fine("SplitStrategy, geomToSplit: " + geomToSplit.toText()); //$NON-NLS-1$
LOGGER.fine("SplitStrategy, split line: " + usefulSplitLineBuilder.getOriginalSplitLine().toText()); //$NON-NLS-1$
splitOp.setSplitLine(usefulSplitLineBuilder);
List<Geometry> splitResult = splitOp.split(geomToSplit);
return splitResult;
}
/**
* Check if it is a valid intersection between the original geometry and the
* split line.
*
* Get the boundary of the polygon geometry and intersects it with the split
* line. A valid split operation must fulfill the next:
*
* <pre>
*
* -The split line must intersect the polygon boundary at least at 2
* points.
* -The line comes from outside the feature, intersects on one point a boundary (interior-exterior),
* the line must have at least one point inside the feature, and then intersects again
* the same boundary(interior-exterior).
* </pre>
*
* @param geomToSplit
* is a LineString, MultilineString, Polygon or MultiPolygon
* @param splitInMapCrs
* a LineString
* @return True if it can split the originalGeometry.
*/
public boolean canSplit(Geometry geomToSplit) {
assert geomToSplit != null : "the Geometry to split musn't be null"; //$NON-NLS-1$
Class<?> geometryClass = geomToSplit.getClass();
SpecificSplitOp splitOp = findSplitStrategy(geometryClass);
UsefulSplitLineBuilder usefulSplitLineBuilder = UsefulSplitLineBuilder.newInstance(getSplitLine());
LOGGER.fine("SplitStrategy, geomToSplit: " + geomToSplit.toText()); //$NON-NLS-1$
LOGGER.fine("SplitStrategy, split line: " + usefulSplitLineBuilder.getOriginalSplitLine().toText()); //$NON-NLS-1$
splitOp.setSplitLine(usefulSplitLineBuilder);
boolean bool = splitOp.canSplit(geomToSplit);
return bool;
}
/**
* Depending on the class of the Geometry to be split, found the
* correspondent class responsible of doing the split operation.
*
* @param geomToSplitClass
* Class of the geometry to be split.
* @return The class responsible of doing split.
*/
private SpecificSplitOp findSplitStrategy(Class<?> geomToSplitClass) {
assert strategies.containsKey(geomToSplitClass) : Messages.SplitStrategy_illegal_geometry + geomToSplitClass;
return strategies.get(geomToSplitClass);
}
/**
* Strategy object for split geometry, subclasses are targeted towards
* specific kinds of geometry.
* <p>
* The GeometryCollectionSplitter will hold onto a LineString provided by
* the user, and use it to break provided geometry one by one.
*/
private static interface SpecificSplitOp {
/**
* LineString used for splitting; as provided by the user.
*
* @param splitLine
* LineString used by the split method to break up geometry
* one by one.
*/
public void setSplitLine(final UsefulSplitLineBuilder splitLine);
public boolean canSplit(Geometry geomToSplit);
/**
* Split the provided Geometry using the LineString provided by the
* user.
*
* @param geomToSplit
* Geometry to split using the user supplied lineString
* @return A list of geometries containing the result geometries.
*/
public List<Geometry> split(Geometry geomToSplit);
/**
* Get the split line.
*
* @return The split line.
*/
public UsefulSplitLineBuilder getSplitLine();
}
/**
* Hold onto a LineString for use by subclasses.
*
*/
private static abstract class AbstractSplitter implements SpecificSplitOp {
private UsefulSplitLineBuilder usefulSplitLineBuilder;
/**
* Sets the split line.
*
* @param splitter
* split line.
*/
public void setSplitLine(final UsefulSplitLineBuilder splitLine) {
this.usefulSplitLineBuilder = splitLine;
}
/**
* Return a copy of split line (defensive copy)
*
* @return The split line.
*/
public UsefulSplitLineBuilder getSplitLine() {
return this.usefulSplitLineBuilder;
}
}
/**
* User the lineString provided by the user to break up lineStrings one by
* one.
*/
private static class LineStringSplitter extends AbstractSplitter {
/**
* Split method used for lineStrings.
*
* @param geomToSplit
* the {@link LineString} to be split.
* @return the resultant geometry.
*/
public List<Geometry> split(Geometry geomToSplit) {
LineString lineString = (LineString) geomToSplit;
LineString splitLine = getSplitLine().getOriginalSplitLine();
Geometry result = lineString.difference(splitLine);
List<Geometry> listLines = new ArrayList<Geometry>();
// for each geometry, add to the list.
for (int i = 0; i < result.getNumGeometries(); i++) {
listLines.add(result.getGeometryN(i));
}
return listLines;
}
public boolean canSplit(Geometry lineString) {
if (!(lineString instanceof LineString)){
throw new IllegalArgumentException("LineString is spected"); //$NON-NLS-1$
}
LineString splitLine = getSplitLine().getOriginalSplitLine();
return splitLine.intersects(lineString) ;
}
} // end LineStringSplitter class
/**
* Strategy object for splitting (a geometry collection).
* <p>
* The GeometryCollectionSplitter will hold onto the SpecificcSplitOp in
* order to hold onto the LineString provided by the user for splitting.
*
*/
private static abstract class AbstractGeometryCollectionSplitter implements SpecificSplitOp {
/** Used to split a single geometry */
private SpecificSplitOp splitter;
private UsefulSplitLineBuilder splitLineBuilder;
/**
* Constructor.
*
* @param spliterOperation
* Specific split operation class.
*/
private AbstractGeometryCollectionSplitter(SpecificSplitOp spliterOperation) {
this.splitter = spliterOperation;
}
/**
* Update the singlePartSplitter with the provided LineString.
*
* @param splitLine
* LineString used by split method to split provided geometry
* one by one
*/
public final void setSplitLine(UsefulSplitLineBuilder splitLine) {
this.splitLineBuilder = splitLine;
this.splitter.setSplitLine(splitLine);
}
/**
* @return The split line.
*/
public UsefulSplitLineBuilder getSplitLine() {
return this.splitLineBuilder;
}
/**
* Split method for polygons and multiPolygons.
*
* @param geomToSplit
*
* @return The resultant geometries.
*/
public final List<Geometry> split(final Geometry geomToSplit) {
final GeometryCollection coll = (GeometryCollection) geomToSplit;
final int numParts = coll.getNumGeometries();
List<Geometry> result = new ArrayList<Geometry>();
for (int partN = 0; partN < numParts; partN++) {
Geometry simplePartN = coll.getGeometryN(partN);
// for multiGeometry, the geometry that is intersected, split
// it, the one that isn't, add without changes.
if (this.splitter.canSplit(simplePartN)) {
List<Geometry> splittedPart = this.splitter.split(simplePartN);
result.addAll(splittedPart);
} else {
result.add(simplePartN);
}
}
return result;
}
public boolean canSplit(Geometry geomToSplit) {
if( !((geomToSplit instanceof MultiPolygon) || (geomToSplit instanceof MultiLineString)) ){
throw new IllegalArgumentException("MultiPolygon or MultiLineString geometry is expected" ); //$NON-NLS-1$
}
final GeometryCollection coll = (GeometryCollection) geomToSplit;
final int numParts = coll.getNumGeometries();
for (int partN = 0; partN < numParts; partN++) {
Geometry currentGeometry = coll.getGeometryN(partN);
if (this.splitter.canSplit(currentGeometry)) {
return true;
}
}
return false;
}
/**
* Build a geometry collection with the provided parts.
*
* @param gf
* Provided geometry factory.
* @param parts
* Split parts.
* @return The geometry collection with the geometries after being
* split.
*/
protected abstract GeometryCollection buildFromParts(GeometryFactory gf, List<?> parts);
} // end AbstractGeometryCollectionSplitter class
/**
* Class responsible for doing split of MultiLineString geometries.
*/
private static class MultiLineStringSplitter extends AbstractGeometryCollectionSplitter {
/**
* Default constructor.
*/
public MultiLineStringSplitter() {
super(new LineStringSplitter());
}
@Override
protected GeometryCollection buildFromParts(GeometryFactory gf, List<?> parts) {
LineString[] lines = parts.toArray(new LineString[parts.size()]);
MultiLineString result = gf.createMultiLineString(lines);
return result;
}
public boolean canSplit(Geometry multiLine) {
if (!(multiLine instanceof MultiLineString)){
throw new IllegalArgumentException("LineString is spected"); //$NON-NLS-1$
}
// lines doesn't needed to be checked.
LineString splitLine = getSplitLine().getOriginalSplitLine();
return splitLine.intersects(multiLine) ;
}
}
/**
* Class responsible for doing split of MultiPolygon geometries.
*/
private static class MultiPolygonSplitter extends AbstractGeometryCollectionSplitter {
/**
* Default constructor.
*/
public MultiPolygonSplitter() {
super(new PolygonSplitter());
}
@Override
protected GeometryCollection buildFromParts(GeometryFactory gf, List<?> parts) {
Polygon[] polygons = parts.toArray(new Polygon[parts.size()]);
MultiPolygon result = gf.createMultiPolygon(polygons);
return result;
}
// public boolean canSplit(Geometry mutiPolygon) {
// if(!(mutiPolygon instanceof MultiPolygon)){
// throw new IllegalArgumentException("MultiPolygon geometry is expected"); //$NON-NLS-1$
// }
// UsefulSplitLineBuilder splitBuilder = this.getSplitLine();
//
// return SplitUtil.canSplitPolygon(mutiPolygon, splitBuilder);
// }
}
/**
* Responsible for splitting a single polygon; polygon may be split into
* several parts (or a hole may be formed).
*
* Polygon Strategy:
* <ul>
* <li>1- Build a graph with all the edges and nodes from the intersection
* between the polygon and the line
* <li>2- Go through the graph, building the new polygons.
* <li>2.1- Get a non-visited edge from the intersection with the line, and
* go through it.
* <li>2.2- Get the next edges, if exist an intersection with other edges,
* take the one with less angle, CW direction. If not, take the next. Add
* the edge.
* <li>2.3- Do the same with the non-visited shell edges and holes. The next
* edges will be calculated with the less angles in CCW direction.
* <li>2.4- Analysis. Once all the rings are created, check that all
* intersection edges (those edges belong to 2 features) are visited twice.
* </ul>
*
*/
private static class PolygonSplitter extends AbstractSplitter {
private List<LinkedHashSet<SplitEdge>> interiorRings = new ArrayList<LinkedHashSet<SplitEdge>>();
private GeometryFactory geometryFactory;
/**
* Split the provided geometry.
*
* @param geomToSplit
* Polygon geometry to split.
*
* @return split geometry or null.
*/
public List<Geometry> split(Geometry geomToSplit) {
assert geomToSplit instanceof Polygon;
final Polygon polygon = (Polygon) geomToSplit;
final List<Geometry> splitPolygon;
LineString splitLine = getSplitLine().getOriginalSplitLine();
if (SplitUtil.isClosedLine(splitLine)) {
splitPolygon = splitPolygonClosedLines(polygon);
} else {
splitPolygon = splitPolygon(polygon);
}
return splitPolygon;
}
/**
* Split the provided polygon.
*
* @param aPolygon
* The source polygon to split.
* @return Return a single polygon or multiPolygon depending on how the
* split went.
*/
private List<Geometry> splitPolygon(final Polygon aPolygon) {
this.geometryFactory = aPolygon.getFactory();
final UsefulSplitLineBuilder splitLine = getSplitLine();
SplitGraphBuilder graphBuilder = new SplitGraphBuilder(aPolygon, splitLine);
graphBuilder.build();
final Graph graph = graphBuilder.getResultantGraph();
// fill the list with all the directedEdge that are forward
// direction.
List<DirectedEdge> directedEdgeList = new LinkedList<DirectedEdge>();
Iterator<?> it = graph.getEdgeEnds().iterator();
while (it.hasNext()) {
DirectedEdge de = (DirectedEdge)it.next();
if (de.isForward()) {
directedEdgeList.add(de);
}
}
List<LinkedHashSet<SplitEdge>> allTheRings = new ArrayList<LinkedHashSet<SplitEdge>>();
// Get a non-visited edge from the intersection, and go through
// it with building rings. Get an edge from the shell.
// After that, if still exist and edge from the holes that wasn't
// visited, go through it.
List<LinkedHashSet<SplitEdge>> ringList = new ArrayList<LinkedHashSet<SplitEdge>>();
ringList = findRing(directedEdgeList);
allTheRings.addAll(ringList);
// analyze the graph assuring all the interior edges has been taken
// into account twice.
ringList = checkRings(directedEdgeList);
allTheRings.addAll(ringList);
// get the non-split edges.
List<LinearRing> nonSplitHoles = getNonSplitHoles( graphBuilder);
// Build the resultant polygon.
List<Geometry> resultingPolygons = buildSimplePolygons(allTheRings, nonSplitHoles);
return resultingPolygons;
}
/**
* Get the non split holes. The interior rings are calculated while
* finding rings, and also while construction the graph.
*
* @param graph
* The split graph.
* @return A list with the holes that weren't modified.
*/
private List<LinearRing> getNonSplitHoles( SplitGraphBuilder graph) {
final List<LinearRing> nonSplitHoles = new ArrayList<LinearRing>();
for (LinkedHashSet<SplitEdge> edgeList : this.interiorRings) {
List<LinearRing> rings = buildLinearRing(edgeList);
nonSplitHoles.addAll(rings);
}
Set<LinearRing> holes = graph.getNonSplitRings();
for (LinearRing hole : holes) {
nonSplitHoles.add(hole);
}
return nonSplitHoles;
}
/**
* Go through the graph and find the created rings, those rings will be
* the new features. Start finding a ring from an intersection edge if
* it isn't visited. Then go through the shell edges. At this point, the
* edges that form the new polygons are created, go through the hole
* edges that weren't visited, those holes will be interior rings that
* aren't modified. At the end, all the shell edges will be covered.
*
* @param directedEdgeList
* List with all the edges from the graph that are forward.
* @return A list containing rings, those rings will be the new
* pre-polygons.
*/
private List<LinkedHashSet<SplitEdge>> findRing(List<DirectedEdge> directedEdgeList) {
List<LinkedHashSet<SplitEdge>> edgeList = new ArrayList<LinkedHashSet<SplitEdge>>();
// first, find the rings provided by the intersection edges.
edgeList =findIntersectionRings(directedEdgeList,edgeList);
// go through shell DirectEdge
edgeList=findShellRings(directedEdgeList,edgeList);
// then, find the rings taken into account only the holeEdges.
storeHolesRings(directedEdgeList);
return edgeList;
}
/**
* Store the rings obtained from the holes edges in the this.interiorRings list.
*
* @param directedEdgeList
*/
private void storeHolesRings( List<DirectedEdge> directedEdgeList ) {
for (DirectedEdge de : directedEdgeList) {
DirectedEdge startEdge = de;
SplitEdge edge = (SplitEdge) startEdge.getEdge();
// get one of the holesEdge but calculate the angle seeking
// which edge is nearest at CCW direction.
if (!edge.isVisited() && edge.isHoleEdge()) {
// check that the edge is only a hole
// edge and not intersection-hole edge.
if (!isOnlyHoleEdge(edge, directedEdgeList)) {
// continue and pick other edge.
continue;
}
LinkedHashSet<SplitEdge> interiorRings = builtRing(startEdge, CGAlgorithms.COUNTERCLOCKWISE);
this.interiorRings.add(interiorRings);
}
}
}
/**
* Find the shell rings.
*
* @param directedEdgeList
* @param edgeList
* @return The edgeList with the "shell rings"
*/
private List<LinkedHashSet<SplitEdge>> findShellRings(
List<DirectedEdge> directedEdgeList,
List<LinkedHashSet<SplitEdge>> edgeList) {
for (DirectedEdge de : directedEdgeList) {
DirectedEdge startEdge = de;
SplitEdge edge = (SplitEdge) startEdge.getEdge();
// Starts from a shell edge
if (!edge.isVisited() && edge.isShellEdge()) {
edgeList.add(builtRing(startEdge,
CGAlgorithms.COUNTERCLOCKWISE));
}
}
return edgeList;
}
/**
* Find the rings provided by the intersection edges.
*
* @param directedEdgeList
* @param edgeList
* @return The edgeList with the "intersection rings"
*/
private List<LinkedHashSet<SplitEdge>> findIntersectionRings(
List<DirectedEdge> directedEdgeList,
List<LinkedHashSet<SplitEdge>> edgeList) {
for (DirectedEdge de : directedEdgeList) {
DirectedEdge startEdge = de;
SplitEdge edge = (SplitEdge) startEdge.getEdge();
// Get one of the intersection edges, and find ring
if (!edge.isVisited() && edge.isIntersectionEdge()) {
// check that the edge is only an intersection
// edge and not intersection-hole edge.
if (!isOnlyIntersectionEdge(edge, directedEdgeList)) {
// continue and pick other edge.
continue;
}
// get the ring.
LinkedHashSet<SplitEdge> result = builtRing(startEdge,
CGAlgorithms.CLOCKWISE);
// It will return null if while building the ring, not all
// the edges are an intersection edges.
if (result != null) {
edgeList.add(result);
}
}
}
return edgeList;
}
/**
* Check if the given edge is unique edge, that means that there isn't
* an intersection edge with the same coordinates.
*
* @param edge
* Edge to find.
* @param directedEdgeList
* List where to find the edge.
* @return True if it is unique edge.
*/
private boolean isOnlyHoleEdge(SplitEdge edge,
List<DirectedEdge> directedEdgeList) {
// compare with the intersection edges.
// go through the DirectEdge
for (DirectedEdge direct : directedEdgeList) {
SplitEdge possibleEdge = (SplitEdge) direct.getEdge();
if (possibleEdge.isIntersectionEdge()) {
if (sameCoordinates(edge.getCoordinates(),
possibleEdge.getCoordinates())) {
return false;
}
}
}
return true;
}
/**
* Check if the given edge is unique edge, that means that there isn't a
* hole edge with the same coordinates.
*
* @param edge
* Edge to find.
* @param directedEdgeList
* List where to find the edge.
* @return True if only exist this intersection edge, any hole edge has
* the same coordinates.
*/
private boolean isOnlyIntersectionEdge(SplitEdge edge,
List<DirectedEdge> directedEdgeList) {
// compare with the holes edges.
// go through the DirectEdge
for (DirectedEdge direct : directedEdgeList) {
SplitEdge possibleHole = (SplitEdge) direct.getEdge();
if (possibleHole.isHoleEdge()) {
if (sameCoordinates(edge.getCoordinates(),
possibleHole.getCoordinates())) {
return false;
}
}
}
return true;
}
/**
* Assure that all the intersection rings have been taken into account
* twice. Each edge belong to 2 features, so it must be visited twice.
* If it was not visited twice, visit it again.
*
* @param directedEdgeList
* List with all the edges from the graph that are forward.
* @return A list containing rings, those rings will be the new
* polygons.
*/
private List<LinkedHashSet<SplitEdge>> checkRings(
List<DirectedEdge> directedEdgeList) {
List<LinkedHashSet<SplitEdge>> edgeList = new ArrayList<LinkedHashSet<SplitEdge>>();
// go through the DirectEdge
for (DirectedEdge de : directedEdgeList) {
DirectedEdge startEdge = de;
SplitEdge edge = (SplitEdge) startEdge.getEdge();
// interior edges must be visited twice, assure all of them
// were processed 2 times.
if (!edge.isTwiceVisited() && edge.isIntersectionEdge()) {
// if the intersection edge is also a hole edge (there are 2
// edges, one belong to an intersection edge and the other
// to the hole, but both of them have the same
// coordinates.), do nothing with it.
if (!intersectionAndHoleSame(directedEdgeList)) {
// get the right direction.
// test with CW direction
int direction = testDirection(startEdge,
CGAlgorithms.CLOCKWISE);
edgeList.add(builtRing(startEdge, direction));
}
}
}
return edgeList;
}
/**
* Seek out if there exist an intersection edge that is exactly as a
* hole edge.
*
* @param directedEdgeList
* The list with the edges.
* @return True if exist an intersect edge that also is a hole edge.
*/
private boolean intersectionAndHoleSame(
List<DirectedEdge> directedEdgeList) {
// go through the DirectEdge
for (DirectedEdge de : directedEdgeList) {
SplitEdge edge = (SplitEdge) de.getEdge();
if (edge.isIntersectionEdge()) {
// compare with the holes edges.
// go through the DirectEdge
for (DirectedEdge direct : directedEdgeList) {
SplitEdge possibleHoleOrShell = (SplitEdge) direct
.getEdge();
if (possibleHoleOrShell.isHoleEdge()
|| possibleHoleOrShell.isShellEdge()) {
if (sameCoordinates(edge.getCoordinates(),
possibleHoleOrShell.getCoordinates())) {
return true;
}
}
}
}
}
return false;
}
/**
* check the coordinates are the same, that means, if the coordinate 1
* equals to the coordinate 2 from the hole, then, the coordinate 2 must
* equal the coordinate 1 from the hole.
*
* @param intersection
* Array containing coordinates from the intersection.
* @param hole
* Array containing coordinates from the hole.
* @return True if a coordinate from the intersection or the hole exists
* on the other side (hole/intersection).
*/
private boolean sameCoordinates(Coordinate[] intersection,
Coordinate[] hole) {
// check the coordinates are the same, that means, if the coordinate
// 1 equals to the coordinate 2 from the hole, then, the coordinate
// 2 must equal the coordinate 1 from the hole.
// the next code could be merged into one single 'if', but this way
// is easier to read it.
if (intersection[0].equals(hole[0])
&& intersection[1].equals(hole[1])) {
return true;
}
if (intersection[1].equals(hole[0])
&& intersection[0].equals(hole[1])) {
return true;
}
if (intersection[0].equals(hole[1])
&& intersection[1].equals(hole[0])) {
return true;
}
if (intersection[1].equals(hole[1])
&& intersection[0].equals(hole[0])) {
return true;
}
return false;
}
/**
* Get the next edges, if exists an intersection with other edges, take
* the one with less angle in the given direction. If not, take the
* next. Add the edge.
*
* @param startEdge
* The directedEdge from which start.
* @param direction
* CCW or CW direction.
* @return A list with a ring of edges.
*/
private LinkedHashSet<SplitEdge> builtRing(
final DirectedEdge startEdge, final int direction) {
DirectedEdge currentDirectedEdge = startEdge;
DirectedEdge nextDirectedEdge = null;
LinkedHashSet<SplitEdge> ring = new LinkedHashSet<SplitEdge>();
while (!edgesAreEqual((SplitEdge) startEdge.getEdge(),
nextDirectedEdge)) {
SplitEdge currentEdge = (SplitEdge) currentDirectedEdge
.getEdge();
ring.add(currentEdge);
currentEdge.countVisited();
DirectedEdge sym = currentDirectedEdge.getSym();
SplitGraphNode endNode = (SplitGraphNode) sym.getNode();
SplitEdgeStar nodeEdges = (SplitEdgeStar) endNode.getEdges();
nextDirectedEdge = nodeEdges.findClosestEdgeInDirection(sym,
direction);
assert nextDirectedEdge != null;
currentDirectedEdge = nextDirectedEdge;
}
return ring;
}
/**
* This function will test if the given direction will form new rings,
* or will form repeated rings. It depends on the line direction, so
* first test with CW direction, if the new ring isn't repeated, thats
* ok.
*
* @param startEdge
* The directedEdge from which start.
* @param direction
* CCW or CW direction.
* @return The correct direction to form the new ring.
*/
private int testDirection(final DirectedEdge startEdge,
final int direction) {
DirectedEdge currentDirectedEdge = startEdge;
DirectedEdge nextDirectedEdge = null;
int finalDirection = direction;
while (!edgesAreEqual((SplitEdge) startEdge.getEdge(),
nextDirectedEdge)) {
SplitEdge currentEdge = (SplitEdge) currentDirectedEdge
.getEdge();
// if thats true, it means that ring already exist, so return
// the opposite direction.
if (currentEdge.isTwiceVisited()) {
finalDirection = (direction == CGAlgorithms.CLOCKWISE) ? CGAlgorithms.COUNTERCLOCKWISE
: CGAlgorithms.CLOCKWISE;
break;
}
DirectedEdge sym = currentDirectedEdge.getSym();
SplitGraphNode endNode = (SplitGraphNode) sym.getNode();
SplitEdgeStar nodeEdges = (SplitEdgeStar) endNode.getEdges();
nextDirectedEdge = nodeEdges.findClosestEdgeInDirection(sym,
direction);
assert nextDirectedEdge != null;
currentDirectedEdge = nextDirectedEdge;
}
return finalDirection;
}
/**
* Check if those edges are equal.
*
* @param startEdge
* Start directedEdge
* @param nextDirectedEdge
* The next one that could be the same as the start.
* @return True if they are equal.
*/
private boolean edgesAreEqual(SplitEdge startEdge,
DirectedEdge nextDirectedEdge) {
if (nextDirectedEdge == null) {
return false;
}
return startEdge.equalsCoordinates(nextDirectedEdge.getEdge());
}
/**
* With the provided rings and the non-split holes, build polygons.
*
* @param allRings
* The ring of the polygon/s.
* @param nonSplitHoles
* Non-split holes.
* @return A list with all the built polygons.
*/
private List<Geometry> buildSimplePolygons(
List<LinkedHashSet<SplitEdge>> allRings,
List<LinearRing> nonSplitHoles) {
List<Geometry> polygons = new ArrayList<Geometry>(allRings.size());
for (LinkedHashSet<SplitEdge> edgeList : allRings) {
// boolean polyIsHole = false;
Polygon poly = buildPolygon(edgeList);
Geometry result = poly;
for (LinearRing holeRing : nonSplitHoles) {
// if it contain a ring, make the difference for creating a
// hole.
if (holeRing.within(poly)) {
Geometry hole = this.geometryFactory.createPolygon(
holeRing, null);
result = result.difference(hole);
}
}
// don't add repeated polygons.
boolean repeated = false;
for (Geometry insertedPol : polygons) {
if (result.equals(insertedPol)) {
repeated = true;
}
}
if (!repeated) {
// add each polygon. There could be more than one result
// only after applying difference with a hole.
for (int i = 0; i < result.getNumGeometries(); i++) {
polygons.add(result.getGeometryN(i));
}
}
}
return polygons;
}
/**
* Build a polygon from a edgeList. This edgeList is a ring of edges.
*
* @param edgeList
* A ring of edges.
* @param gf
* The geometry factory.
* @return The resultant polygon.
*/
private Polygon buildPolygon(LinkedHashSet<SplitEdge> edgeList) {
List<Coordinate> coords = new LinkedList<Coordinate>();
Coordinate[] lastCoordinates = null;
for (SplitEdge edge : edgeList) {
Coordinate[] coordinates = edge.getCoordinates();
if (lastCoordinates != null) {
Coordinate endPoint = lastCoordinates[lastCoordinates.length - 1];
Coordinate startPoint = coordinates[0];
if (!endPoint.equals2D(startPoint)) {
coordinates = CoordinateArrays.copyDeep(coordinates);
CoordinateArrays.reverse(coordinates);
}
}
lastCoordinates = coordinates;
for (int i = 0; i < coordinates.length; i++) {
Coordinate coord = coordinates[i];
coords.add(coord);
}
}
// shell coordinates.
Coordinate[] shellCoords = new Coordinate[coords.size()];
coords.toArray(shellCoords);
shellCoords = CoordinateArrays.removeRepeatedPoints(shellCoords);
// hole/s rings.
List<LinearRing> holeList = new ArrayList<LinearRing>();
LinearRing[] ring;
// even if it hasn't self-intersections, do the first so
// LinearRing[] result is filled with values.
do {
ring = extractInteriorRing(shellCoords);
// result[0] is the shell.
// result[1] if exists, is a hole.
if (ring[1] != null) {
holeList.add(ring[1]);
}
shellCoords = new Coordinate[ring[0].getCoordinates().length];
shellCoords = ring[0].getCoordinates();
} while (hasSelfIntersection(shellCoords));
Polygon poly;
if (holeList.isEmpty()) {
poly = this.geometryFactory.createPolygon(ring[0],
(LinearRing[]) null);
} else {
LinearRing[] holes = holeList.toArray(new LinearRing[holeList
.size()]);
poly = this.geometryFactory.createPolygon(ring[0], holes);
}
return poly;
}
/**
* Check the coordinates seeking for self-intersection, that means, seek
* for repeated coordinates.
*
* @param shellCoords
* Shell coordinates off the polygon.
* @return True if it has self-intersection.
*/
private boolean hasSelfIntersection(Coordinate[] shellCoords) {
// check if it has self-intersections
for (int i = 1; i < shellCoords.length; i++) {
Coordinate actualCoord = shellCoords[i];
for (int j = i + 1; j < shellCoords.length - 1; j++) {
Coordinate selfIntersectionCoord = shellCoords[j];
if (actualCoord.equals2D(selfIntersectionCoord)) {
// here we have a self intersection coordinate.
return true;
}
}
}
return false;
}
/**
* Go through the shell coordinates seeking for self-intersections and
* extract them. Then those extracted rings will be inserted as holes of
* the polygon.
*
* @param shellCoords
* Shell coordinates off the polygon.
* @return 2 linearRing, one will be the shell and the other a hole if
* exists.
*/
private LinearRing[] extractInteriorRing(Coordinate[] shellCoords) {
// check for self-intersection
// the shell coordinates can't have self-intersection, if a
// self-intersection is found, the coordinates between then will
// form an interior ring.
// take into account that the first and last coordinate are the
// same.
int selfIntersectionStart = -1;
int selfIntersectionEnd = -1;
for (int i = 1; i < shellCoords.length
&& selfIntersectionStart == -1; i++) {
Coordinate actualCoord = shellCoords[i];
for (int j = i + 1; j < shellCoords.length - 1; j++) {
Coordinate selfIntersectionCoord = shellCoords[j];
if (actualCoord.equals2D(selfIntersectionCoord)) {
// here we have a self intersection coordinate.
selfIntersectionStart = i;
selfIntersectionEnd = j;
break;
}
}
}
LinearRing[] shellAndHole = new LinearRing[2];
List<Coordinate> shell = new LinkedList<Coordinate>();
List<Coordinate> hole = new LinkedList<Coordinate>();
for (int j = 0; j < shellCoords.length; j++) {
// add the actual shell coordinate
shell.add(shellCoords[j]);
if (j == selfIntersectionStart) {
// retrieve the interior ring.
for (int i = selfIntersectionStart; i <= selfIntersectionEnd; i++) {
hole.add(shellCoords[i]);
}
// move the cursor to continue after the
// self-intersection coordinate
j = selfIntersectionEnd;
}
}
shellAndHole[0] = this.geometryFactory.createLinearRing(shell
.toArray(new Coordinate[shell.size()]));
if (hole.size() != 0) {
shellAndHole[1] = this.geometryFactory.createLinearRing(hole
.toArray(new Coordinate[hole.size()]));
} else {
shellAndHole[1] = null;
}
return shellAndHole;
}
/**
* From those interior rings (holes), build linearRings. Those rings
* will be the new split features, or an existent ring that has not been
* modified.
*
* @param edgeList
* List of splitEdges.
* @return The linearRing of the holes.
*/
private List<LinearRing> buildLinearRing(
LinkedHashSet<SplitEdge> edgeList) {
List<Coordinate> coords = new ArrayList<Coordinate>();
Coordinate[] lastCoordinates = null;
for (SplitEdge edge : edgeList) {
Coordinate[] coordinates = edge.getCoordinates();
if (lastCoordinates != null) {
Coordinate endPoint = lastCoordinates[lastCoordinates.length - 1];
Coordinate startPoint = coordinates[0];
if (!endPoint.equals2D(startPoint)) {
coordinates = CoordinateArrays.copyDeep(coordinates);
CoordinateArrays.reverse(coordinates);
}
}
lastCoordinates = coordinates;
for (int i = 0; i < coordinates.length; i++) {
Coordinate coord = coordinates[i];
coords.add(coord);
}
}
Coordinate[] shellCoords = new Coordinate[coords.size()];
coords.toArray(shellCoords);
shellCoords = CoordinateArrays.removeRepeatedPoints(shellCoords);
// hole/s rings.
List<LinearRing> holeList = new ArrayList<LinearRing>();
LinearRing[] result;
// even if it hasn't self-intersections, do the first so
// LinearRing[] result is filled with values.
do {
// shellCoords could have nested rings(self-intersected), so
// extract them.
// find which one has self-intersections.
result = extractInteriorRing(shellCoords);
if (hasSelfIntersection(result[0].getCoordinates())) {
// the remaining hole is on result[0]
// result[1] if exists, is a nested hole, but now is
// separate.
if (result[1] != null) {
holeList.add(result[1]);
}
// result[0] is the remaining hole.
shellCoords = new Coordinate[result[0].getCoordinates().length];
shellCoords = result[0].getCoordinates();
} else if (result[1] != null
&& hasSelfIntersection(result[1].getCoordinates())) {
// the remaining hole is on result[1]
// result[0] if exists, is a nested hole, but now is
// separate.
if (result[0] != null) {
holeList.add(result[0]);
}
// result[1] is the remaining hole.
shellCoords = new Coordinate[result[1].getCoordinates().length];
shellCoords = result[1].getCoordinates();
} else {
// no one has intersections, so fill the shellCoords with
// result[0] or result[1], it doesn't matter.
shellCoords = new Coordinate[result[0].getCoordinates().length];
shellCoords = result[0].getCoordinates();
}
} while (hasSelfIntersection(shellCoords));
// add the last holes, result[0] and result[1] if exists.
holeList.add(result[0]);
if (result[1] != null) {
holeList.add(result[1]);
}
return holeList;
}
/**
* <p>
*
* <pre>
* Split operation for polygons using closed lines.
* First extract the rings and the remaining line from the
* closed line with the aid of the {@link RingExtractor}.
* Second make the operation using {@link SplitClosedLines}.
* </pre>
*
* </p>
*
* @param polygon
* Polygon that will suffer the split operation.
* @return List with the resultant polygons.
*/
private List<Geometry> splitPolygonClosedLines(final Polygon polygon) {
LineString splitLine = getSplitLine().getOriginalSplitLine();
RingExtractor ringExtractor = new RingExtractor(splitLine);
ResultRingExtractor data = ringExtractor.processExtraction();
SplitClosedLines closedLines = new SplitClosedLines(data);
return closedLines.runClosedLineSplit(polygon);
}
public boolean canSplit(Geometry polygon) {
if(!(polygon instanceof Polygon)){
throw new IllegalArgumentException("Polygon geometry is expected"); //$NON-NLS-1$
}
UsefulSplitLineBuilder splitBuilder = this.getSplitLine();
return SplitUtil.canSplitPolygon(polygon, splitBuilder);
}
}
}