/* This program 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 3 of the License, or (at your option) any later version. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.opentripplanner.common.geometry; import java.util.ArrayList; import java.util.List; import java.util.Random; import junit.framework.TestCase; import org.geotools.referencing.GeodeticCalculator; import org.junit.Test; import com.vividsolutions.jts.geom.Coordinate; public class DirectionUtilsTest extends TestCase { @Test public final void testAzimuth() { final int N_RUN = 1000000; GeodeticCalculator geodeticCalculator = new GeodeticCalculator(); Random rand = new Random(42); List<Coordinate> from = new ArrayList<>(N_RUN); List<Coordinate> to = new ArrayList<>(N_RUN); // Add fixed points from.add(new Coordinate(0, 45)); to.add(new Coordinate(0, 45)); // Undefined: 180 deg assertTrue(DirectionUtils.getAzimuth(from.get(0), to.get(0)) == 180); from.add(new Coordinate(0, 45)); to.add(new Coordinate(0.1, 45)); // East: 90 deg assertTrue(DirectionUtils.getAzimuth(from.get(1), to.get(1)) == 90); from.add(new Coordinate(0, 45)); to.add(new Coordinate(0, 45.1)); // North: 0 deg assertTrue(DirectionUtils.getAzimuth(from.get(2), to.get(2)) == 0); from.add(new Coordinate(0, 45)); to.add(new Coordinate(-0.1, 45)); // West: -90 deg assertTrue(DirectionUtils.getAzimuth(from.get(3), to.get(3)) == -90); from.add(new Coordinate(0, 45)); to.add(new Coordinate(0, 44.9)); // South: 180 deg assertTrue(DirectionUtils.getAzimuth(from.get(4), to.get(4)) == 180); for (int i = 0; i < N_RUN; i++) { Coordinate a = new Coordinate(rand.nextDouble() * 0.1, 45 + rand.nextDouble() * 0.1); Coordinate b = new Coordinate(rand.nextDouble() * 0.1, 45 + rand.nextDouble() * 0.1); from.add(a); to.add(b); } double[] exactAzimuths = new double[from.size()]; double[] approxAzimuths = new double[to.size()]; long start = System.currentTimeMillis(); for (int i = 0; i < from.size(); i++) { geodeticCalculator.setStartingGeographicPoint(from.get(i).x, from.get(i).y); geodeticCalculator.setDestinationGeographicPoint(to.get(i).x, to.get(i).y); exactAzimuths[i] = geodeticCalculator.getAzimuth(); } long exactTimeMs = System.currentTimeMillis() - start; System.out.println("GeodeticCalculator exact azimuth: " + exactTimeMs + "ms for " + N_RUN + " computations."); start = System.currentTimeMillis(); for (int i = 0; i < from.size(); i++) { approxAzimuths[i] = DirectionUtils.getAzimuth(from.get(i), to.get(i)); } long approxTimeMs = System.currentTimeMillis() - start; System.out.println("UtilsDistance approx azimuth: " + approxTimeMs + "ms for " + N_RUN + " computations."); double maxError = 0.0; for (int i = 0; i < exactAzimuths.length; i++) { double error = (exactAzimuths[i] - approxAzimuths[i]); // Degrees if (error > 360) error -= 360; if (error < -360) error += 360; if (error > maxError) maxError = error; } System.out.println("Max error in azimuth: " + maxError + " degrees."); assertTrue(maxError < 0.15); } }