com.vividsolutions.jts.geom.prep.PreparedLineStringIntersects Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of JTSplus Show documentation
JTS Topology Suite 1.14 with additional functions for GeoSpark
There is a newer version: 0.1.4
/*
 * 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.geom.prep;

import java.util.*;


import com.vividsolutions.jts.algorithm.*;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.noding.*;
import com.vividsolutions.jts.geom.util.*;

/**
 * Computes the intersects spatial relationship predicate
 * for a target {@link PreparedLineString} relative to other {@link Geometry} classes.
 * Uses short-circuit tests and indexing to improve performance. 
 * 
 * @author Martin Davis
 *
 */
class PreparedLineStringIntersects 
{
	/**
	 * Computes the intersects predicate between a {@link PreparedLineString}
	 * and a {@link Geometry}.
	 * 
	 * @param prep the prepared linestring
	 * @param geom a test geometry
	 * @return true if the linestring intersects the geometry
	 */
	public static boolean intersects(PreparedLineString prep, Geometry geom)
	{
		PreparedLineStringIntersects op = new PreparedLineStringIntersects(prep);
    return op.intersects(geom);
	}

	protected PreparedLineString prepLine;

  /**
   * Creates an instance of this operation.
   * 
   * @param prepPoly the target PreparedLineString
   */
	public PreparedLineStringIntersects(PreparedLineString prepLine)
	{
		this.prepLine = prepLine;
	}
	
	/**
	 * Tests whether this geometry intersects a given geometry.
	 * 
	 * @param geom the test geometry
	 * @return true if the test geometry intersects
	 */
	public boolean intersects(Geometry geom)
	{
		/**
		 * If any segments intersect, obviously intersects = true
		 */
    List lineSegStr = SegmentStringUtil.extractSegmentStrings(geom);
    // only request intersection finder if there are segments (ie NOT for point inputs)
    if (lineSegStr.size() > 0) {
  		boolean segsIntersect = prepLine.getIntersectionFinder().intersects(lineSegStr);
  		// MD - performance testing
  //		boolean segsIntersect = false;
  		if (segsIntersect) 
        return true;
    }
		/**
		 * For L/L case we are done
		 */
		if (geom.getDimension() == 1) return false;
		
		/**
		 * For L/A case, need to check for proper inclusion of the target in the test
		 */
		if (geom.getDimension() == 2
				&& prepLine.isAnyTargetComponentInTest(geom)) return true;
		
		/** 
		 * For L/P case, need to check if any points lie on line(s)
		 */
		if (geom.getDimension() == 0)
			return isAnyTestPointInTarget(geom);
		
		return false;
	}
	  
  /**
   * Tests whether any representative point of the test Geometry intersects
   * the target geometry.
   * Only handles test geometries which are Puntal (dimension 0)
   * 
   * @param geom a Puntal geometry to test
   * @return true if any point of the argument intersects the prepared geometry
   */
	protected boolean isAnyTestPointInTarget(Geometry testGeom)
	{
		/**
		 * This could be optimized by using the segment index on the lineal target.
		 * However, it seems like the L/P case would be pretty rare in practice.
		 */
		PointLocator locator = new PointLocator();
    List coords = ComponentCoordinateExtracter.getCoordinates(testGeom);
    for (Iterator i = coords.iterator(); i.hasNext(); ) {
      Coordinate p = (Coordinate) i.next();
      if (locator.intersects(p, prepLine.getGeometry()))
        return true;
    }
		return false;
	}

}