/*
* 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.relate;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.geotools.geometry.iso.coordinate.EnvelopeImpl;
import org.geotools.geometry.iso.root.GeometryImpl;
import org.geotools.geometry.iso.topograph2D.Dimension;
import org.geotools.geometry.iso.topograph2D.Edge;
import org.geotools.geometry.iso.topograph2D.EdgeEnd;
import org.geotools.geometry.iso.topograph2D.EdgeIntersection;
import org.geotools.geometry.iso.topograph2D.GeometryGraph;
import org.geotools.geometry.iso.topograph2D.IntersectionMatrix;
import org.geotools.geometry.iso.topograph2D.Label;
import org.geotools.geometry.iso.topograph2D.Location;
import org.geotools.geometry.iso.topograph2D.Node;
import org.geotools.geometry.iso.topograph2D.NodeMap;
import org.geotools.geometry.iso.topograph2D.index.SegmentIntersector;
import org.geotools.geometry.iso.util.Assert;
import org.geotools.geometry.iso.util.algorithm2D.LineIntersector;
import org.geotools.geometry.iso.util.algorithm2D.PointLocator;
import org.geotools.geometry.iso.util.algorithm2D.RobustLineIntersector;
/**
* Computes the topological relationship between two Geometries.
* <p>
* RelateComputer does not need to build a complete graph structure to compute
* the IntersectionMatrix. The relationship between the geometries can be
* computed by simply examining the labelling of edges incident on each node.
* <p>
* RelateComputer does not currently support arbitrary GeometryCollections. This
* is because GeometryCollections can contain overlapping Polygons. In order to
* correct compute relate on overlapping Polygons, they would first need to be
* noded and merged (if not explicitly, at least implicitly).
*
*
*
* @source $URL$
*/
public class RelateComputer {
private LineIntersector li = new RobustLineIntersector();
private PointLocator ptLocator = new PointLocator();
private GeometryGraph[] arg; // the arg(s) of the operation
private NodeMap nodes = new NodeMap(new RelateNodeFactory());
// this intersection matrix will hold the results compute for the relate
//private IntersectionMatrix im = null;
private ArrayList isolatedEdges = new ArrayList();
// the intersection point found (if any)
//private Coordinate invalidPoint;
public RelateComputer(GeometryGraph[] arg) {
this.arg = arg;
}
/**
* Computes the Intersection Matrix for the two given geometry objects
* @return Intersection Matrix
*/
public IntersectionMatrix computeIM() {
IntersectionMatrix tIM = new IntersectionMatrix();
// since Geometries are finite and embedded in a 2-D space, the EE
// element must always be 2
tIM.set(Location.EXTERIOR, Location.EXTERIOR, 2);
// if the Geometries don't overlap there is nothing to do
// if (!arg[0].getGeometry().getEnvelopeInternal().intersects(
// arg[1].getGeometry().getEnvelopeInternal())) {
EnvelopeImpl env1 = (EnvelopeImpl) arg[0].getGeometry().getEnvelope();
EnvelopeImpl env2 = (EnvelopeImpl) arg[1].getGeometry().getEnvelope();
if (!env1.intersects(env2)) {
computeDisjointIM(tIM);
return tIM;
}
this.arg[0].computeSelfNodes(this.li, false);
this.arg[1].computeSelfNodes(this.li, false);
// compute intersections between edges of the two input geometries
SegmentIntersector tIntersector =
this.arg[0].computeEdgeIntersections(this.arg[1], this.li, false);
this.computeIntersectionNodes(0);
this.computeIntersectionNodes(1);
// Copy the labelling for the nodes in the parent Geometries. These
// override any labels determined by intersections between the
// geometries.
this.copyNodesAndLabels(0);
this.copyNodesAndLabels(1);
// complete the labelling for any nodes which only have a label for a
// single geometry
this.labelIsolatedNodes();
// If a proper intersection was found,
// we can set a lower bound on the IM.
this.computeProperIntersectionIM(tIntersector, tIM);
// Now process improper intersections (e.g. where one or other of the
// geometries has a vertex at the intersection point) We need to compute
// the edge graph at all nodes to determine the IM.
// build EdgeEnds for all intersections
EdgeEndBuilder eeBuilder = new EdgeEndBuilder();
List ee0 = eeBuilder.computeEdgeEnds(arg[0].getEdgeIterator());
this.insertEdgeEnds(ee0);
List ee1 = eeBuilder.computeEdgeEnds(arg[1].getEdgeIterator());
this.insertEdgeEnds(ee1);
this.labelNodeEdges();
// Compute the labeling for isolated components <br>
// Isolated components are components that do not touch any other
// components in the graph. They can be identified by the fact that they
// will contain labels containing ONLY a single element, the one for
// their parent geometry. We only need to check components contained in
// the input graphs, since isolated components will not have been
// replaced by new components formed by intersections.
this.labelIsolatedEdges(0, 1);
this.labelIsolatedEdges(1, 0);
// update the IM from all components
this.updateIM(tIM);
return tIM;
}
private void insertEdgeEnds(List ee) {
for (Iterator i = ee.iterator(); i.hasNext();) {
EdgeEnd e = (EdgeEnd) i.next();
nodes.add(e);
}
}
private void computeProperIntersectionIM(SegmentIntersector intersector,
IntersectionMatrix im) {
// If a proper intersection is found, we can set a lower bound on the
// IM.
// int dimA = arg[0].getGeometry().getDimension();
// int dimB = arg[1].getGeometry().getDimension();
int dimA = arg[0].getGeometry().getDimension(null);
int dimB = arg[1].getGeometry().getDimension(null);
boolean hasProper = intersector.hasProperIntersection();
boolean hasProperInterior = intersector.hasProperInteriorIntersection();
// For Geometry's of dim 0 there can never be proper intersections.
/**
* If edge segments of Areas properly intersect, the areas must properly
* overlap.
*/
if (dimA == 2 && dimB == 2) {
if (hasProper)
im.setAtLeast("212101212");
}
/**
* If an Line segment properly intersects an edge segment of an Area, it
* follows that the Interior of the Line intersects the Boundary of the
* Area. If the intersection is a proper <i>interior</i> intersection,
* then there is an Interior-Interior intersection too. Note that it
* does not follow that the Interior of the Line intersects the Exterior
* of the Area, since there may be another Area component which contains
* the rest of the Line.
*/
else if (dimA == 2 && dimB == 1) {
if (hasProper)
im.setAtLeast("FFF0FFFF2");
if (hasProperInterior)
im.setAtLeast("1FFFFF1FF");
} else if (dimA == 1 && dimB == 2) {
if (hasProper)
im.setAtLeast("F0FFFFFF2");
if (hasProperInterior)
im.setAtLeast("1F1FFFFFF");
}
/*
* If edges of LineStrings properly intersect *in an interior point*,
* all we can deduce is that the interiors intersect. (We can NOT deduce
* that the exteriors intersect, since some other segments in the
* geometries might cover the points in the neighbourhood of the
* intersection.) It is important that the point be known to be an
* interior point of both Geometries, since it is possible in a
* self-intersecting geometry to have a proper intersection on one
* segment that is also a boundary point of another segment.
*/
else if (dimA == 1 && dimB == 1) {
if (hasProperInterior)
im.setAtLeast("0FFFFFFFF");
}
}
/**
* Copy all nodes from an arg geometry into this graph. The node label in
* the arg geometry overrides any previously computed label for that
* argIndex. (E.g. a node may be an intersection node with a computed label
* of BOUNDARY, but in the original arg Geometry it is actually in the
* interior due to the Boundary Determination Rule)
*/
private void copyNodesAndLabels(int argIndex) {
for (Iterator i = arg[argIndex].getNodeIterator(); i.hasNext();) {
Node graphNode = (Node) i.next();
Node newNode = nodes.addNode(graphNode.getCoordinate());
newNode.setLabel(argIndex, graphNode.getLabel().getLocation(
argIndex));
}
}
/**
* Insert nodes for all intersections on the edges of a Geometry. Label the
* created nodes the same as the edge label if they do not already have a
* label. This allows nodes created by either self-intersections or mutual
* intersections to be labelled. Endpoint nodes will already be labelled
* from when they were inserted.
*
* @param argIndex
*/
private void computeIntersectionNodes(int argIndex) {
for (Iterator i = this.arg[argIndex].getEdgeIterator(); i.hasNext();) {
Edge e = (Edge) i.next();
int eLoc = e.getLabel().getLocation(argIndex);
for (Iterator eiIt = e.getEdgeIntersectionList().iterator(); eiIt
.hasNext();) {
EdgeIntersection ei = (EdgeIntersection) eiIt.next();
RelateNode n = (RelateNode) this.nodes.addNode(ei.coord);
if (eLoc == Location.BOUNDARY)
n.setLabelBoundary(argIndex);
else {
if (n.getLabel().isNull(argIndex))
n.setLabel(argIndex, Location.INTERIOR);
}
}
}
}
/**
* For all intersections on the edges of a Geometry, label the corresponding
* node IF it doesn't already have a label. This allows nodes created by
* either self-intersections or mutual intersections to be labelled.
* Endpoint nodes will already be labelled from when they were inserted.
*/
private void labelIntersectionNodes(int argIndex) {
for (Iterator i = arg[argIndex].getEdgeIterator(); i.hasNext();) {
Edge e = (Edge) i.next();
int eLoc = e.getLabel().getLocation(argIndex);
for (Iterator eiIt = e.getEdgeIntersectionList().iterator(); eiIt
.hasNext();) {
EdgeIntersection ei = (EdgeIntersection) eiIt.next();
RelateNode n = (RelateNode) nodes.find(ei.coord);
if (n.getLabel().isNull(argIndex)) {
if (eLoc == Location.BOUNDARY)
n.setLabelBoundary(argIndex);
else
n.setLabel(argIndex, Location.INTERIOR);
}
// n.print(System.out);
}
}
}
/**
* If the Geometries are disjoint, we need to enter their dimension and
* boundary dimension in the EXTERIOR rows in the IM
*/
private void computeDisjointIM(IntersectionMatrix im) {
GeometryImpl ga = arg[0].getGeometry();
// if (!ga.isEmpty()) {
// im.set(Location.INTERIOR, Location.EXTERIOR, ga.getDimension());
// im.set(Location.BOUNDARY, Location.EXTERIOR, ga
// .getBoundaryDimension());
// }
im.set(Location.INTERIOR, Location.EXTERIOR, ga.getDimension(null));
if (ga.getBoundary() == null) {
im.set(Location.BOUNDARY, Location.EXTERIOR, Dimension.FALSE);
}
else {
im.set(Location.BOUNDARY, Location.EXTERIOR, ga.getBoundary().getDimension(null));
}
GeometryImpl gb = arg[1].getGeometry();
// if (!gb.isEmpty()) {
// im.set(Location.EXTERIOR, Location.INTERIOR, gb.getDimension());
// im.set(Location.EXTERIOR, Location.BOUNDARY, gb
// .getBoundaryDimension());
// }
im.set(Location.EXTERIOR, Location.INTERIOR, gb.getDimension(null));
if (gb.getBoundary() == null) {
im.set(Location.EXTERIOR, Location.BOUNDARY, Dimension.FALSE);
}
else {
im.set(Location.EXTERIOR, Location.BOUNDARY, gb.getBoundary().getDimension(null));
}
}
private void labelNodeEdges() {
for (Iterator ni = nodes.iterator(); ni.hasNext();) {
RelateNode node = (RelateNode) ni.next();
node.getEdges().computeLabelling(arg);
}
}
/**
* Update the IM with the sum of the IMs for each component
*
* @param IntersectionMatrix
*/
private void updateIM(IntersectionMatrix im) {
for (Iterator ei = isolatedEdges.iterator(); ei.hasNext();) {
Edge e = (Edge) ei.next();
e.updateIM(im);
}
for (Iterator ni = nodes.iterator(); ni.hasNext();) {
RelateNode node = (RelateNode) ni.next();
//System.out.println(node.getCoordinate());
node.updateIM(im);
node.updateIMFromEdges(im);
}
}
/**
* Processes isolated edges by computing their labelling and adding them to
* the isolated edges list. Isolated edges are guaranteed not to touch the
* boundary of the target (since if they did, they would have caused an
* intersection to be computed and hence would not be isolated)
*
* @param thisIndex
* @param targetIndex
*/
private void labelIsolatedEdges(int thisIndex, int targetIndex) {
for (Iterator ei = arg[thisIndex].getEdgeIterator(); ei.hasNext();) {
Edge e = (Edge) ei.next();
if (e.isIsolated()) {
this.labelIsolatedEdge(e, targetIndex, arg[targetIndex]
.getGeometry());
isolatedEdges.add(e);
}
}
}
/**
* Label an isolated edge of a graph with its relationship to the target
* geometry. If the target has dim 2 or 1, the edge can either be in the
* interior or the exterior. If the target has dim 0, the edge must be in
* the exterior
*/
private void labelIsolatedEdge(Edge e, int targetIndex, GeometryImpl target) {
// this won't work for GeometryCollections with both dim 2 and 1 geoms
// if (target.getDimension() > 0) {
if (target.getDimension(null) > 0) {
// since edge is not in boundary, may not need the full generality
// of PointLocator?
// Possibly should use ptInArea locator instead? We probably know
// here
// that the edge does not touch the bdy of the target Geometry
int loc = ptLocator.locate(e.getCoordinate(), target);
e.getLabel().setAllLocations(targetIndex, loc);
} else {
e.getLabel().setAllLocations(targetIndex, Location.EXTERIOR);
}
}
/**
* Isolated nodes are nodes whose labels are incomplete (e.g. the location
* for one Geometry is null). This is the case because nodes in one graph
* which don't intersect nodes in the other are not completely labelled by
* the initial process of adding nodes to the nodeList. To complete the
* labelling we need to check for nodes that lie in the interior of edges,
* and in the interior of areas.
*/
private void labelIsolatedNodes() {
for (Iterator ni = nodes.iterator(); ni.hasNext();) {
Node n = (Node) ni.next();
Label label = n.getLabel();
// isolated nodes should always have at least one geometry in their
// label
Assert.isTrue(label.getGeometryCount() > 0,
"node with empty label found");
if (n.isIsolated()) {
if (label.isNull(0))
labelIsolatedNode(n, 0);
else
labelIsolatedNode(n, 1);
}
}
}
/**
* Label an isolated node with its relationship to the target geometry.
*/
private void labelIsolatedNode(Node n, int targetIndex) {
int loc = ptLocator.locate(n.getCoordinate(), arg[targetIndex]
.getGeometry());
n.getLabel().setAllLocations(targetIndex, loc);
}
}