EnhancedPrecisionOpExample.java

/*
 * 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.jtsexample.precision;

import com.vividsolutions.jts.io.WKTReader;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.precision.EnhancedPrecisionOp;

/**
 * Example of using {@link EnhancedPrecisionOp} to avoid robustness problems
 *
 * @version 1.7
 */
public class EnhancedPrecisionOpExample
{
  public static void main(String[] args) throws Exception
  {
    EnhancedPrecisionOpExample example = new EnhancedPrecisionOpExample();
    try {
      example.run();
    }
    catch (Exception ex) {
      ex.printStackTrace();
    }
  }

  private WKTReader reader = new WKTReader();

  public EnhancedPrecisionOpExample() {
  }

  void run()
      throws Exception
  {
    String wkt1, wkt2;
    // two geometries which cause robustness problems
    wkt1 = "POLYGON ((708653.498611049 2402311.54647056, 708708.895756966 2402203.47250014, 708280.326454234 2402089.6337791, 708247.896591321 2402252.48269854, 708367.379593851 2402324.00761653, 708248.882609455 2402253.07294874, 708249.523621829 2402244.3124463, 708261.854734465 2402182.39086576, 708262.818392579 2402183.35452387, 708653.498611049 2402311.54647056))";
    wkt2 = "POLYGON ((708258.754920656 2402197.91172757, 708257.029447455 2402206.56901508, 708652.961095455 2402312.65463437, 708657.068786251 2402304.6356364, 708258.754920656 2402197.91172757))";
    Geometry g1 = reader.read(wkt1);
    Geometry g2 = reader.read(wkt2);

    System.out.println("This call to intersection will throw a topology exception due to robustness problems:");
    try {
      Geometry result = g1.intersection(g2);
    }
    catch (TopologyException ex) {
      ex.printStackTrace();
    }

    System.out.println("Using EnhancedPrecisionOp allows the intersection to be performed with no errors:");
    Geometry result = EnhancedPrecisionOp.intersection(g1, g2);
    System.out.println(result);
  }


}