com.vividsolutions.jts.noding.NodingValidator Maven / Gradle / Ivy
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/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* 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; either
* version 2.1 of the License, or (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* For more information, contact:
*
* Vivid Solutions
* Suite #1A
* 2328 Government Street
* Victoria BC V8T 5G5
* Canada
*
* (250)385-6040
* www.vividsolutions.com
*/
package com.vividsolutions.jts.noding;
import java.util.*;
import com.vividsolutions.jts.algorithm.*;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.util.*;
/**
* Validates that a collection of {@link SegmentString}s is correctly noded.
* Throws an appropriate exception if an noding error is found.
*
* @version 1.7
*/
public class NodingValidator {
private LineIntersector li = new RobustLineIntersector();
private Collection segStrings;
public NodingValidator(Collection segStrings)
{
this.segStrings = segStrings;
}
public void checkValid()
{
// MD - is this call required? Or could it be done in the Interior Intersection code?
checkEndPtVertexIntersections();
checkInteriorIntersections();
checkCollapses();
}
/**
* Checks if a segment string contains a segment pattern a-b-a (which implies a self-intersection)
*/
private void checkCollapses()
{
for (Iterator i = segStrings.iterator(); i.hasNext(); ) {
SegmentString ss = (SegmentString) i.next();
checkCollapses(ss);
}
}
private void checkCollapses(SegmentString ss)
{
Coordinate[] pts = ss.getCoordinates();
for (int i = 0; i < pts.length - 2; i++) {
checkCollapse(pts[i], pts[i + 1], pts[i + 2]);
}
}
private void checkCollapse(Coordinate p0, Coordinate p1, Coordinate p2)
{
if (p0.equals(p2))
throw new RuntimeException("found non-noded collapse at "
+ Debug.toLine(p0, p1, p2));
}
/**
* Checks all pairs of segments for intersections at an interior point of a segment
*/
private void checkInteriorIntersections()
{
for (Iterator i = segStrings.iterator(); i.hasNext(); ) {
SegmentString ss0 = (SegmentString) i.next();
for (Iterator j = segStrings.iterator(); j.hasNext(); ) {
SegmentString ss1 = (SegmentString) j.next();
checkInteriorIntersections(ss0, ss1);
}
}
}
private void checkInteriorIntersections(SegmentString ss0, SegmentString ss1)
{
Coordinate[] pts0 = ss0.getCoordinates();
Coordinate[] pts1 = ss1.getCoordinates();
for (int i0 = 0; i0 < pts0.length - 1; i0++) {
for (int i1 = 0; i1 < pts1.length - 1; i1++) {
checkInteriorIntersections(ss0, i0, ss1, i1);
}
}
}
private void checkInteriorIntersections(SegmentString e0, int segIndex0, SegmentString e1, int segIndex1)
{
if (e0 == e1 && segIndex0 == segIndex1) return;
//numTests++;
Coordinate p00 = e0.getCoordinates()[segIndex0];
Coordinate p01 = e0.getCoordinates()[segIndex0 + 1];
Coordinate p10 = e1.getCoordinates()[segIndex1];
Coordinate p11 = e1.getCoordinates()[segIndex1 + 1];
li.computeIntersection(p00, p01, p10, p11);
if (li.hasIntersection()) {
if (li.isProper()
|| hasInteriorIntersection(li, p00, p01)
|| hasInteriorIntersection(li, p10, p11)) {
throw new RuntimeException("found non-noded intersection at "
+ p00 + "-" + p01
+ " and "
+ p10 + "-" + p11);
}
}
}
/**
*@return true if there is an intersection point which is not an endpoint of the segment p0-p1
*/
private boolean hasInteriorIntersection(LineIntersector li, Coordinate p0, Coordinate p1)
{
for (int i = 0; i < li.getIntersectionNum(); i++) {
Coordinate intPt = li.getIntersection(i);
if (! (intPt.equals(p0) || intPt.equals(p1)))
return true;
}
return false;
}
/**
* Checks for intersections between an endpoint of a segment string
* and an interior vertex of another segment string
*/
private void checkEndPtVertexIntersections()
{
for (Iterator i = segStrings.iterator(); i.hasNext(); ) {
SegmentString ss = (SegmentString) i.next();
Coordinate[] pts = ss.getCoordinates();
checkEndPtVertexIntersections(pts[0], segStrings);
checkEndPtVertexIntersections(pts[pts.length - 1], segStrings);
}
}
private void checkEndPtVertexIntersections(Coordinate testPt, Collection segStrings)
{
for (Iterator i = segStrings.iterator(); i.hasNext(); ) {
SegmentString ss = (SegmentString) i.next();
Coordinate[] pts = ss.getCoordinates();
for (int j = 1; j < pts.length - 1; j++) {
if (pts[j].equals(testPt))
throw new RuntimeException("found endpt/interior pt intersection at index " + j + " :pt " + testPt);
}
}
}
}